Rain Gardens Across Maryland - Worcester County

ainardensAcross MarylandCleaning Maryland’s waterways one rain garden at a time.

PrefaceIntroductionIf you enjoyed reading Rain Gardens in Maryland’sCoastal Plain, you will enjoy reading Rain GardensAcross Maryland. This new and improved “how-to”manual discusses the benefits of incorporatingmultiple small-scale practices into a rain gardendesign. You will also learn how to: Reduce impervious surfaces Size your rain garden to capture themaximum rainfall amount Select rain garden plants native to Maryland Install rain barrels Measure your rain garden’s performanceEnvironmental Site DesignFor homeowners required to install stormwatermanagement practices, this manual providesenvironmental site design, or ESD sizing criteria forrain gardens. Just look for “ESD criteria” textboxes. The ESD criteria outlines the minimumrequirements homeowners shall implement in order tosatisfy Maryland’s stormwater regulations and shouldbe approved by your local approving authority beforeyou begin building your rain garden. Homeownersinstalling rain gardens voluntarily do not have to meetESD criteria.Title 4, Subtitle 201.1(B) of the StormwaterManagement Act of 2007 defines an ESD as usingsmall-scale stormwater management practices,nonstructural techniques, and better site planning tomimic natural hydrologic runoff characteristics andminimize the impact of land development on waterresources to the maximum extent practical. Underthis definition, ESD includes: Minimizing impervious surfaces Conserving natural features e.g., drainagepatterns, soil, vegetation Slowing down runoff to maintain dischargetiming and to increase infiltration Using other nonstructural practices orinnovative technologies approved by theMaryland Department of the EnvironmentSmall-scale practicesSmall-scale practices capture and treat stormwaterrunoff from impervious areas usually less than oneacre in size. These practices typically include naturalsystems, vegetation, and soils and may beinterconnected to create a more natural drainagesystem. Although this manual focuses on installingrain gardens, the ESD strategy requires thatstormwater management practices, including thesmall-scale practices listed below, be integrated intoone project to the maximum extent practical. Smallscalepractices include: Rain gardens Rainwater harvesting Submerged gravel wetlands Landscape infiltration Infiltration berms Dry wells Micro bioretention Swales Enhanced filtersStormwater Design ManualThe primary goal of Maryland’s stormwatermanagement program is to maintain predevelopmentrunoff characteristics as nearly as possible. The ESDcriteria provides a comprehensive design strategy toachieve this goal and is described in Maryland’sStormwater Design Manual. To learn more about theMaryland Department of the Environment’s approvedrain garden ESD sizing criteria and other approvedsmall-scale practices, refer to chapter 5 of theMaryland Stormwater Design Manual, “EnvironmentalSite Design.” This document can also be found athttp://www.mde.state.md.us/Programs/WaterPrograms/SedimentandStormwater/swm2007.asp.ii

Table of ContentsIntroduction ................................................................................... 1Location ............................................................................................. 5Sizing ................................................................................................. 9Rain Garden Sizing Worksheet ................................................... 14Construction ..................................................................................... 17Planting .............................................................................................. 23Maintenance ..................................................................................... 29Rain Garden Checklist .................................................................... 32Appendices ....................................................................................... 33References ....................................................................................... 44Acknowledgements ......................................................................... 45Special Thanks ................................................................................. 47iii

Figure 1. As runoff passes through the soil mixture, chemical and biological processes break down the pollutants. This helpsprotect the Atlantic Coastal and Chesapeake Bays from fertilizers, oils, and other pollutants carried by runoff.

IntroductionFigure 2. Rain gardens absorb rainwater flowing from roofs, lawns and other impervious surfaces.Homeowners across Maryland areimproving water quality, reducingflooding, and increasing their propertyvalues by adding rain gardens to theirlandscape (figure 2). A typical raingarden consists of a shallow depressionthat is a planting bed of native plants,loose soil, mulch, and sometimes stone.Together, these elements collect,absorb, and clean runoff.Well designed rain gardens collect andsoak up rainwater that flows off ofhard surfaces. Commonly referred toas stormwater runoff, the rainwaterspreads throughout the rain garden. Asthe stormwater runoff passes throughthe soil mixture, physical and biologicalprocesses such as plant uptake andadsorption to soil particles removepollutants and nutrients in stormwaterrunoff (figure 1).ESD Criteria # 1. DefinitionA rain garden is a shallow, excavatedlandscape feature or a saucer-shapeddepression that temporarily holdsrunoff for a short period of time. Raingardens typically consist of anabsorbent-planted soil bed, a mulchlayer and planting materials such asshrubs, grasses and flowers (figure 1).An overflow conveyance system isincluded to pass larger storms.Captured runoff from downspouts,roof drains, pipes, swales, or curbopenings temporarily ponds and slowlyfilters into the soil over 24 to 48hours.Source: Maryland’s StormwaterManagement Act of 2007,Environment Article 4 §201.1 and§203. ff.Introduction1

Your rain garden(s) can help infiltrate100% of the runoff in your drainagearea with proper planning. That’s lessrunoff entering storm drains thateventually flow into our waterways andultimately the Atlantic Coastal andChesapeake Bays (figure 3). In additionto cleaning our waterways, rain gardensalso help:Replenish groundwater resourcesProtect structures andlandscapingEnhance the beauty of yardsProvide wildlife habitatYou can contribute to cleaner water bybuilding a rain garden in yourlandscape. By using this document tohelp guide you through the rain gardenplanning and building process, you willlearn how to:Locate your rain gardenSize your rain gardenBuild your rain gardenSelect native plantsMaintain your rain gardenFigure 3. When hard surfaces prevent rainwater fromseeping into the ground it will flow into drain systemscarrying with it pollutants and nutrients. Thestormwater, if left untreated, can harm our localstreams, creeks, rivers, and lakes and everythingdependent on clean healthy waterways.ESD Criteria # 2. Micro-scalePracticeRain gardens can be primary orsecondary practices on residential,commercial, industrial, or institutionalsites. This practice is typically used totreat runoff from small imperviousareas like rooftops, driveways andsidewalks. Rain gardens can also beused in retrofitting and redevelopmentapplications and in a series whereexisting slopes require energydissipation.2 Introduction

Rain Garden FactsDoes a rain garden form a pondor wetland?No. The rainwater will soak into theground within 24-48 hours after astorm (figure 4).Will a rain garden become amosquito breeding ground?No. Mosquitoes lay eggs in standingwater. Rain gardens do not holdrainwater long enough for mosquitoesto reproduce successfully (figure 5).Figure 4. Don’t be surprised if your rain garden haswater in it after a storm. It’s supposed to. The raingarden installed across from the town hall in HighlandBeach, Maryland is strategically placed to collect runofffrom the road and lawns.Does a rain garden require a lotof maintenance?No. Established native plants requireno more maintenance than any othertype of garden. Native speciesgenerally require less maintenance ifthey are planted in the right place.They do not need fertilizers,pesticides, or additional water otherthan what nature provides (unlessthere is a severe drought).Figure 5. The rain garden installed across from theHighland Beach Town Hall drains water after eachstorm. Well designed rain gardens drain 24-48 hoursafter a storm.Is a rain garden expensive tobuild and maintain?No. With any gardening project, thecost is related to the location, size,labor, tools, supplies and materials, andplants. To keep the costs low, invitefamily and friends to help build therain garden (figure 6) and buyperennials. Your one-time investmentwill come back each growing season.Figure 6. Sweat equity cuts costs. Shown above,volunteers install a shade rain garden at theChesapeake Ecology Center in Annapolis, Maryland.Introduction3

Figure 7. Identify existing landscaping features relative to your house to help locate the best place to build your rain garden. Thiscan help you capture runoff from impervious surfaces and improve your landscape.

This section explains how to locateyour rain garden by answering thefollowing questions:1. What elements should youconsider when choosing alocation for your rain garden?2. What type of soil do you have?3. What shape should it be?1. Where?To determine where to build your raingarden, you will need a goodunderstanding of the layout of youryard. To begin, identify existinglandscaping features and hard surfaceslike the driveway, any outbuildings, andhouse (figure 7). Map these featureson paper to help you begin envisioningwhere a rain garden could be built.Consider the tips below to help youchoose the best rain garden location.When it rains, watch the flow ofwater on and around yourproperty. Using arrows, drawthe movement of water fromyour house or driveway (bothgoing away from or toward yourhouse). You’ll begin to see thedirection runoff flows towardsstorm drains or waterways.Locate your rain garden so thatit intercepts the runoff beforeflowing into these outlets.Low-lying wet areas wherewater naturally ponds after aheavy storm may be good areasfor your rain garden too.LocationESD Criteria # 3. LocationLot-by-lot use of rain gardens is notrecommended in residentialsubdivisions due to subsequent removalby homeowners. If used on a lot-by-lotbasis, educating the homeowners willbe needed to prevent removal. Aneducational sign similar to the oneshown below in figure 8 is helpful. Raingarden excavation in areas with heavytree cover may damage adjacent treeroot systems.Figure 8. Install rain garden signs to raiseawareness.ESD Criteria #4. InfrastructureThe location of existing and proposedbuildings and utilities (e.g., watersupply wells, sewer, storm drains,electricity) will influence rain gardendesign and construction. Landscapedesigners should also consideroverhead telecommunication andelectrical lines when selecting trees tobe planted. Read the “Construction”section to learn more (pages 17-21).Location5

Figure 9. The rain garden installed more than 30 feet from the house has a larger drainage area than the gardenlocated within 30 feet of the house. The farthest garden will likely capture and treat more runoff.The best location for the raingarden is in partial to full sun.Locate rain gardens downslopefrom a downspout, driveway orother impervious surfaces tocapture and treat more runoff(figure 9).Rain gardens should be at least25 feet away from a septicdrain field or well head and 10feet away from a dwellingfoundation to prevent waterfrom seeping into basements orESD Criteria # 5. SoilsClay soils or soils that have beencompacted by construction equipmentgreatly reduce the effectiveness ofrain gardens. Loosening of compactedsoils may improve drainage capability.crawl spaces. Check with yourlocal approving agency foradditional guidance.Level or gently sloping sitesrequire the least amount ofdigging.Think about the views of yourrain garden within the existinglandscape from differentperspectives, including insidethe house.1. Your rain garden is _____ feet from the.(impervious surface)2. Identify soil typeCheck the soil type of your rain gardensite before you begin digging. Your soiltype influences the garden’s drainageand size. If your rain garden is sandy,6 Location

Figure 10. A quick sketch can help you visualize the garden’s location. Its longest side should be oriented tointercept runoff flowing downhill and from any direct sources of runoff like a downspout.then you have the best drainage andcan build the garden smaller than thosebuilt on clay or silt laden sites.To identify your soil type put some soilin your hands. If the soil feels grittyand coarse, it’s probably sandy soil.Silty soil, however, feels smooth butnot sticky. Clay soils are very stickyand plastic-like to handle when wet.You’ll be able to form a ball with it. Avisual inspection can also indicate thesoil type at your site. If you still havestanding water 24 hours after a rainevent then you probably have some claysoils at the site.Rain garden areas high in clay contentmay require you to amend the nativesoil with a rain garden planting soilmixture (read pages 20 and 21 formore information). Another option is toselect another rain garden location. Ifyou are unsure about your soil type,refer to appendix A for other types ofsoil tests.2. Your soil type is sand silt or clay.3. ShapeOnce you’ve picked out the location foryour rain garden, determine its shape.Your rain garden can be any shape—crescent or kidney shapes areattractive—but a long and narrow raingarden works well if you are placing itbetween structures, such as a drivewayand patio. Long rain gardens cancapture the greatest amount of runoffif located properly (figure 10).3. Your rain garden’s shape is a .Location7

Figure 11. Make sure your rain garden surface ponding depth is deep enough to hold runoff, allowing it to gradually soak into thenative soils.

SizingFigure 12: Your drainage area may include impervious surfaces like portions of the lawn (highlighted in blue), roof,sidewalk, and driveway (highlighted in red). These elements can direct more stormwater runoff into rain gardens.This section provides guidance onsizing your rain garden to capture atleast 70% of the runoff for theaverage yearly rainfall. In Maryland,the annual average rainfall is 42 inches.To capture 100% of the runoff from aspecific storm event, refer toappendix B to determine your rainfalldepth. You can skip to page 15 todetermine how to size your gardenbased on targeting a rainfall amount.Reading through this section, however,will help you understand what you willneed to consider when sizing your raingarden. You can adapt these guidelinesto meet your site’s unique conditionsand personal water quality goals. Readfurther to learn about these topics:1. Impervious surfaces2. Improving your drainage area3. Sizing your rain garden4. Quantifying performanceSizing1. Impervious surfacesImpervious surfaces in your drainagearea prevent water from seeping intothe ground, thereby increasing theamount of stormwater runoff capturedin your rain garden. The rain garden,shown in figure 12, is located less than30 feet from a roof downspout and hasa drainage area that includes theportion of the roof that feeds thedownspout and any ground level hardsurfaces that slope to the rain garden.ESD Criteria # 6. TreatmentThe rainfall amount used to size ESDpractices shall be applied to thecontributing drainage area. ESDpractices shall be used to treat therunoff from one inch of rainfall on allnew developments where stormwatermanagement is required.9

Figure 13. Permeable pavers installed at the Back Creek Nature Park in Annapolis, Maryland provide a solid groundsurface that can support vehicles.The rain garden located more than 30feet from the house can capture morerunoff because of the increasedamount of impervious surfaces,including the lawn (which can bepartially impervious), deck, roof,sidewalk, and driveway.2. Improving your drainage areaConsider reducing impervious surfaceson your property to reduce the amountof runoff entering your rain garden byreplacing asphalt with permeablepavers or permeable concrete. Theyprovide a solid ground surface, strongenough to take heavy loads, like largevehicles, while at the same timeallowing water to filter through thesurface and reach the underlying soils(figure 13). Permeable pavers are alsoideal for patios, sidewalks, anddriveways. The voids in the surface ofthe paving allow water to drain throughand into the soil beneath. Other10 Sizingbenefits of permeable pavers andpermeable concrete include:Increased groundwaterrecharge and/or storage,thereby lessening surfacepuddles and local flooding.Reduced stream bank erosionand downstream flooding.Capturing of nearly 100% ofpolluted runoff depending onproject design parameters,thereby mitigating impact onsurrounding surface waters.Decreased project cost byreducing retention/detentionsystems and runoff.Minimization of impacts andstress on existing storm sewersystems through reduced peakdischarges.Reduced heat island effect andthermal loading on surroundingsurface waters.

Faster snow melt on permeablepavement and drains, reducingwinter ice hazards, deicing saltuse, and snow removal costs.Another way to improve your drainagearea is to divert flows away fromimpervious surfaces. This is known asnon-rooftop disconnection. Simplydirect flow from impervious surfacesonto vegetated areas, where it cansoak into or filter over the ground.This will disconnect these surfacesfrom the storm drain system, reducingrunoff volume and pollutants deliveredto waterways.Non-rooftop disconnection is commonlyapplied to smaller or narrowerimpervious areas like driveways, opensection roads, and small parking lotsand depends on several site conditions(e.g., permeable flow path length, soils,slopes, compaction) to function well.Consider how you can improve yourdrainage area as you work through thefollowing calculations that will helpdetermine your rain garden’s size.3. DimensionsTo determine the dimensions of yourrain garden, you’ll need to do a littlemath to assess the following:3a. Drainage area3b. Ponding depth3c. Rain garden area3d. Width and length3a. Calculate drainage areaThe following five steps will help youdetermine your drainage area.Figure 14. In the example above, the roof is about 60feet by 40 feet. The total roof area is 2,400 ft 2 .Figure 15. In the example above, about 25% of thetotal roof area feeds water to the downspout.1. Estimate the total roof area (insquare feet), roof area=lengthx width (figure 14).2. Estimate the percentage of rooffeeding the downspout(figure 15).1. The roof drainage area (RDA)equals the total roof areamultiplied by the percentage ofroof feeding a downspout(see sample calculation below).RDA = (40’ x 60’ ) x 25%RDA = 2,400 ft 2 x 25%RDA = 600 ft 24. Calculate the ground surfacearea draining to the site bymultiplying its length and width.Sizing11

ESD Criteria # 7. Target rainfallDuring the project planning andpreliminary design, site soils andproposed imperviousness are used todetermine target rainfall for sizingESD practices to mimic woodedconditions (refer to page 15).ESD Criteria # 8. Drainage AreaA rain garden’s drainage area serving asingle lot in a residential subdivisionshall be 2,000 ft 2 or less. Themaximum drainage area for all otherapplications shall be 10,000 ft 2 . Microbioretentionor bioretention should beconsidered when these requirementsare exceeded.ESD Criteria # 9. TopographyRain gardens require relatively flatslopes (

Figure 16: A rain garden with a 5% slope (shown above) should have a surface ponding depth of 5 inches (table 1below). A surface ponding depth of 9 inches will allow for 3-4 inches of a topping layer.string’s length and multiply theresult by 100. A samplecalculation is provided below.Slope % = (9”/180”) x 100Slope % = 0.05 x 100Slope % = 5%Slope: %Use table 1 below to determine yourgarden’s surface ponding depth. AddSlopeLess than 5%Equal to or greaterthan 5-7%Equal to or greaterthan 7-12%Equal to or greaterthan 12%Surface PondingDepth5 inches deep6-7 inches deep~8 inches deepSelect another site or talkto a professionallandscaperTable 1. Slope and ponding depth reference table.more depth, inch for inch, if you planto spread mulch on the surface. If youhave a more sloping site, you may needto remove or add soil to create a levelbase. Circle the proposed depth below.3b. Ponding depth: 5” 6-7” 8” (circle one)add mulch layer (if any)inches.3c. Determine rain garden areaUse the sizing worksheet on the nextpage to determine your rain garden’sarea. If you decide that the area is toobig consider breaking up the gardenarea into two or three smaller gardens.If you discover that your garden is toosmall to hold the amount of waterflowing into it create an overflow area(e.g., with stone) to relieve excesswater or create a system ofinterconnected rain gardens. Morethan one rain garden can be installed tobetter disperse and absorb runoff.Sizing13

Rain Garden Sizing WorksheetInsert your answers from the previous pages to determine your rain garden’sdimensions. Garden’s distance from impervious surface(s): (page 6) Soil type: (page 7) Shape: (page 7) Drainage area: ft 2 (page 12) Total surface ponding depth: inches (page 13) The size factor is (see table 2 below)Rain Garden Surface Ponding DepthSoil type 5” 6-7” 8” All depthsSand 0.19 0.15 0.08 0.03Silt 0.34 0.25 0.16 0.06Clay 0.43 0.32 0.20 0.10Less than 30 feet More than 30 feetDistance from downspoutSizefactorTable 2. In the table above, the size factor is determined by three items: the rain gardensurface ponding depth, soil type, and distance from the downspout. To determine the sizefactor for your rain garden, locate the intersection of these three items in the table above.For example, a rain garden that has a surface ponding depth of six inches, containssandy soils, and is less than 30 feet from a downspout has a size factor of 0.15. A raingardens installed more than 30 feet away from a downspout and has sandy soils will havea size factor is 0.03 regardless of its surface ponding depth. Rain garden area = ft 2Rain garden area = drainage area x size factor Width = feet (page 15) Length = feet14 Sizing

Figure 17. The shortest side should be 4-10 feet wide to balance the effect of slope with the rain garden depth andis best placed perpendicular to the slope. For lawns with a slope greater than 8%, the maximum recommendedwidth is 15 feet.3d. Determine length and widthEstimating the rain garden length(longest side) and width (shortest side)is based on your garden area, personalpreferences, and a little bit of math.To begin, estimate how wide yourgarden should be by considering yourgarden’s shape and unique siteconditions. This includes the availableyard space, the distance betweenlandscaped areas, and any physicalconstraints. By considering theseelements, you may decide that yourgarden should be 5 feet wide (figure17). You’ve just selected the width ofyour garden. Use the selected width inthe sizing worksheet on the oppositepage to calculate the garden’s length.4. Performance measuresWith a little bit of math work, you canquantify the impact your rain gardenhas on capturing stormwater runoff.SizingFollowing, you will learn how to buildyour rain garden based on a rainfallamount and calculate your drainagearea’s recharge volume.1. Target rainfallMaryland’s environmental site designcriteria for sizing rain gardens arebased on capturing and retainingenough rainfall so that the runoffleaving a site is reduced to a levelequivalent to a wooded site in goodcondition. To estimate the amount ofrainfall treated by your rain gardenuse the formula below.If you would like to capture 100%runoff, refer to appendix B for yourlocal rainfall depth and considerinstalling other small-scale practicesdiscussed on pages 9 to 11 to improveyour drainage capacity.15

Recharge Volume (watershed-inches)A soilsB soilsC soilsD soilsFigure 18. Use the line graph above to plot your site’s imperviousness and recharge volume. For example, if yourrecharge volume equals 0.15 and your site imperviousness equals 20% you are above the minimum rechargevolume for all HSG soils. However, if your site imperviousness is 90% you do not meet the minimum rechargevolume for HSG A or B soils. Additional small-scale practices may be necessary to achieve the site’s rechargevolume. Source: Maryland Stormwater Design Manual, “Unified Stormwater Sizing Criteria”, p 2.6.2. Recharge volumeImpervious surfaces prevent rainfallfrom percolating into the ground,reducing the amount of groundwaterrecharge. This change alters thenatural hydrology of stream andwetland systems and harms the habitatof many aquatic organisms. Exceedingthe minimum recharge volume attemptsto reverse this impact by requiringthat a specific amount of stormwaterHSG - DescriptionSSRFA ~ excessively drained 0.38B ~ well drained 0.26C ~ moderately well drained 0.13D ~ somewhat poorly drained 0.07Table 3. Consult chapter 2 of the Maryland StormwaterDesign Manual, “Unified Stormwater Sizing Criteria”,and chapter 3 of the Natural Resources ConservationService Soil Survey Manual, “Examination andDescription of Soils”, for details.Site Imperviousness (%)16 Sizingbe recharged into the groundwater.Recharge volume is based on thehydrologic soil groups (HSG) at thesite, and the amount of imperviouscover created by the development.Follow the next steps to calculate therecharge volume.1. Referring to table 3, classify yoursoil type within a HSG andidentify the HSG soil specificrecharge factor (SSRF).2. Calculate the drainage area’simperviousness (I).3. Calculate the recharge volume.Recharge volume = SSRF X I4. Plot your drainage area’simperviousness on the line graphabove to evaluate the rechargevolume (figure 18).

ConstructionFigure 19. A sketch of your rain garden can help guide the construction process. In the example above, the raingarden is about 4-8 feet wide and has a surface ponding depth of 5-6 inches. Rocks located at the entrance pointhelps to dissipate runoff and the berm helps to hold water in the rain garden.In this section, you will learn how toprepare the site and dig your raingarden. To help guide you through theconstruction process sketch out thegarden’s dimensions and surroundings.A sketch similar to figure 19 is anexample that can help you duringconstruction.For a self-installed rain garden,expect to pay between $3 and$5 per square foot in plant costsand soil amendments. Whenworking with a landscapingcompany to design and installyour rain garden, the cost willPreparing the siteTo avoid digging on or near utility linesor pipes, contact Miss Utility at1-800-257-7777 or www.missutility.net48 business hours prior to digging. Tobe on the safe side, you may considercontacting Miss Utility one week priorto digging. The following tips will alsohelp you prepare your site for digging.ESD Criteria # 11. InspectionRegular inspections shall be madeduring the following stages ofconstruction.During excavation to subgradeand placement of planting soil.Upon completion of final gradingand establishment of permanentstabilization.Construction17

Figure 20. Bay-Wise master gardeners installed a rain garden at the Chesapeake Ecology Center in Annapolis, MD.ESD Criteria # 12. ConveyanceRunoff shall enter, flow through, andexit rain gardens in a safe and nonerosivemanner.ESD Criteria # 13. Internal slopeA minimum internal slope of 1% shouldbe maintained and a shallow bermsurrounding the rain garden isrecommended to avoid shortcircuiting.For sloped applications, aseries of rain gardens can be used as“scalloped” terraces to convey waternon-erosively (refer to pages 12-13).ESD Criteria # 14. Erosion &Sediment ControlRain gardens shall not be constructeduntil the contributing drainage area isstabilized. During construction, runoffshould be diverted and the use ofheavy equipment avoided to minimizecompaction.significantly increase to around$10 to $15 per square foot.Depending on your rain gardensize you may want additional help(figure 20). Building an averagesizerain garden can take oneperson several hours, while ateam of friends or neighbors candig a rain garden in a fraction ofthe time. With more friends it’salso twice as much fun.At the site use a flat shovel topeel the grass away from thesoil. You might be able to reusethe sod to build a vegetatedberm.If the grass is too tough to peel,cover it with black plastic untilthe grass dies. This usually takes3-4 weeks. Pesticides should onlybe used as a last resort as thiscould harm pets, local wildlife,and nearby plants.18 Construction

Figure 21. Creating a curb cut allows stormwater runoff from streets to enter rain gardens.If possible, plan to install yourrain garden in the late spring orfall when the soil will be easierto dig and when the plants aremore likely to thrive.ExcavationFollow the steps below to begin diggingyour rain garden.1. Capturing runoffBe sure the runoff sources will flow tothe garden site. If your rain gardenwill receive runoff from roadways,make sure curb cuts are created(figure 21 and 22). This assuresrainwater will flow into the garden.2. Outlining the rain garden shapeWhile referring to your sketches, layout the approximate shape of your raingarden with marking paint, heavy rope,or a hose. You can also use surveyorflags or overturn the grass to markthe garden’s edge (figure 23 on page20). Another way to mark the edge isto mow the shape of your garden. Ifyou decide to do so, make the cornersgentle, otherwise they will be difficultto mow. Remove and replace the stakeswhen you are done mowing (refer topage 12). You’ll need the stakes forbuilding a berm. The edge between cutand uncut grass will give you an easy toFigure 22. A curb cut allows runoff to flow into a raingarden at Heritage Baptist Church in Annapolis, MD.Construction19

maintain shape. Be creative with theshape, but gentle curves look the mostnatural.3. Constructing the bermA berm is a low soil mound constructedalong the width and downhill side ofyour rain garden. Its top should beabout level with the uphill side and itsbase should be a foot or more widewith gently sloping sides. Berms on thedownhill side of a garden are necessaryon sloping sites. This will help holdwater in your garden giving it time toseep into the soil.Figure 23. The Lower Eastern Shore Tributary StrategyTeam outlines the garden’s shape by marking it withpaint and overturning sod.To build your berm, consider reusingthe sod and soil from your rain gardenarea (figure 24). This will help create avegetated berm which is more likely towithstand berm erosion.4. Soil mixture (optional)Amend soil only if necessary. If youare planning to remove existing soil inorder to add rain garden soil mixture,make sure you dig a few more inchesbelow the garden base (refer to figure16 on page 13). A soil mixtureconsisting of 50-60% sand, 20-30%topsoil (no clay), and 20-30% compostwill help establish plants and allowwater to soak in. Use the formulabelow to help estimate the amount oftotal fill needed for your garden.Figure 24. To construct the rain garden at the WardMuseum of Wildfowl Art in Salisbury, Maryland, theLower Eastern Shore Tributary Strategy Team reusedthe garden area’s sod to build a vegetated berm alongthe downslope side of the garden.Fill = width x length x depthbelow garden baseFollow the ESD criteria #15 if you arerequired to implement stormwatermanagement by your local approvingauthority.20 Construction

Figure 25. If your level is long enough, use it to level the height of your rain garden berm.5. Putting it all togetherReferring to your sketches, you willknow how deep to dig. If your pondingdepth is 6 inches, you will remove allthe sod and soil 6 inches below thelevel string line. Remember to dig a fewmore inches if you are adding mulch,compost, or soil.Begin digging at the uphill side nearthe stake and place the dirt (and sod)in the berm location. Level the berm’sheight with the uphill side by eyeballingit, moving the downhill stakealong the lower edge of the rain gardenwhile making sure the string is level, orby placing a carpenter’s level on astraight 2x4 that reaches from theuphill side to the berm (figure 25).Now that the rain garden is dug youare ready to plant herbaceousflowering perennials (flowers andgrasses) or woodies (shrubs and trees)in your garden. Read the next sectionto learn how to select and install nativeplants in your rain garden.ESD Criteria # 15. Planting SoilPlanting soil should be mixed on–siteprior to installation. If poor soils areencountered beneath the rain garden,a four–inch layer of washed gravel (1/8to 3/8 inch gravel preferred) may beused below the planting soil mix. Theplanting soil and mulch shall conformto the specifications found in appendixB.4 of the Maryland StormwaterDesign Manual atwww.mde.state.md.us/Programs/WaterPrograms/SedimentandStormwater/stormwater_design/index.asp.Construction21

Marsh MarigoldSpiderwortTall White BeardtongueFigure 26. Rain gardens add color and life to your landscape.Swamp MilkweedBlueflag IrisBlueberry Bush

PlantingFigure 27. Sketch out your basic rain garden design. You don’t have to be an architect!With the grunt work done, you’re nowready to bring your rain garden to lifewith your native plant selection (figure26). In this section, you will learn howto select plants, lay out a rain gardendesign, install plants, and apply mulch.Rain garden designCreate a sketch of your rain gardendesign to help guide your plantselection (figure 27). To help youbrainstorm, refer to appendix C for asample design and review the tipsbelow.For a bold impact, reduce theamount of space between plantsby a few inches from theESD Criteria # 16. DesignLandscaping plans shall clearly specifyhow vegetation will be established andmanaged. A rain garden should belocated in full to partial sun, at leasttwo feet above the seasonal highwater table and have a total raingarden depth of 12 to 18 inches (referto figure 11 on page 8). Plants selectedfor use in the rain garden shouldtolerate both saturated and dryconditions and be native or adapted toMaryland. Neatly trimmed shrubs, acrisp lawn edge, stone retaining walls,and other devices can be used to keepa rain garden neat and visuallyappealing.Planting23

Figure 28. Clustering creates the visual impact in the rain garden along Lincoln Drive in Annapolis, MD.recommended spacing. Thisallows mature plants to overlap.Plant your native shrubs andflowers where their uniquetextures, colors, and heights willcomplement one another andhelp achieve the desired visualimpact. Like grade-schoolpictures, tallest in the back andshortest up front.Plant SelectionNative plants create habitat suited forwildlife, grow well without chemicalsupplements, and require lessmaintenance. With native species, yourrain garden will be beautiful, healthy,and safely enjoyed by insects, birds,pets, and children. Decide which nativeplants meet your personal preferencesby referring to appendix D for a list ofnative plants or visit your local nursery.Online resources like the Native Plantsfor Wildlife Habitat and ConservationLandscaping: Chesapeake BayWatershed, www.RainScaping.org, andThe Low Impact Development Centeralso provide helpful tips on how tochoose the plants for your garden andprovides pictures of them too. Beloware some tips to help you select plants.Sun, partial sun, and shadeSelect native plants adapted to thesunlight your rain garden will receive.Height, color, and textureThe physical properties of your plantswill help add variety and interest toyour rain garden. If your rain gardenlacks flowering blooms, then takeadvantage of different leaf shades,shapes, and colors. For example,combining a variety of textures,staggering heights, and plants bearingvariegation increases visual interest ifclustered properly (figure 28).24 Planting

Figure 29. White Turtlehead.ClusterLike real estate, landscaping has threerules: cluster, cluster, and cluster. Buyat least three individual plants of eachspecies, but seven is typically theminimum number for a cluster.BloomsDesign your rain garden to be “alive”spring through fall by selecting plantsthat bloom throughout the seasons.For example, beardtongue blooms fromApril to June and cardinal flower, ahummingbird favorite, blooms fromJuly to September (see front cover).White turtlehead (figure 29) bloomsfrom August to October and is the onlyplant that the Maryland state insect,the Baltimore Checkerspot Butterfly,will lay its eggs on (figure 30). Bydesigning your garden to bloom yearround with native plants, local insectsand wildlife will benefit too.Figure 30. Baltimore Checkerspot Butterfly.RootsBuy one or two-year old plants withwell-established root systems that arebeginning to circle or mat the pot, yetare young enough to adapt well to newgrowing conditions.Incorporating clusters of ferns,rushes, and grasses with yourflowering plants creates good rootcompetition. This is normal and causesa healthier root pattern to develop.Blending a mix of clustered plantspecies reduces the chance of thegarden being overrun by one species.If you would like to plant shrubs andtrees, make sure they are well adaptedto at least part-time wet conditions.Plant!While referring to your rain gardendesign sketch, place the potted plantsin your rain garden. Try to visualizethem full grown and move them aroundPlanting25

Figure 31. Lower Eastern Shore Tributary Team members and volunteers planted native grasses, flowers, andshrubs at one of two rain gardens installed at the Providence Presbyterian Church in Salisbury, MD.ESD Criteria # 17. LandscapeInstallationThe optimum planting time is duringthe Fall. Spring planting is alsoacceptable but may require watering.ESD Criteria# 18. ConveyanceRunoff shall enter a rain garden at thesurface through grass swales and/or agravel bed. Energy dissipation shall beprovided for downspout dischargesusing a plunge area, rocks, splashblocks, stone dams, etc.ESD Criteria # 19. TreatmentA minimum layer of 6-12 inchesof planting soil shall be provided(refer to figure 11 on page 8).A mulch layer 2-3 inches deepshall be applied to the plantingsoil to maintain soil moisture andto prevent premature clogging.until you’ve reached the best effect.Be bold, but cluster! The following tipswill help you begin planting your pottedplants.Dig each hole so it is at leasttwice as wide as the pot and nodeeper than the pot. You willknow if the hole is deep enoughwhen the pot’s soil and theplant’s crown are level with theexisting grade.Plant one plant at a time fromone side to the other or fromthe middle out to avoid steppingon plants.Remove the plants by tappingthe side of the pots to loosenthem. Do not expose plant rootsany longer than necessary.Loosen the matted roots circlingwith the shape of the pot.26 Planting

Figure 32. The rain garden above, designed by Kara Bowne Crissey and installed by the Severn Grove EcologicalDesign, placed rocks along the edge to dissipate runoff during storm events.Place the plant in the hole, fillthe hole with soil, and firmlytamp it.Water your plants immediately.To help remember what’s what,put plant labels next to eachcluster.With the helping hand of a friend, youwill be able finish in an hour or two(figure 31). Once all are planted, roundup your pots and either reuse orrecycle them.Toppings: stone and mulchUntil the native plants can establishthemselves, spread stone across theentrance point of your rain garden toslow water flow (figure 32). This willalso help prevent strong storm eventsfrom washing out the mulch, soil, orbreaking through the berm. To lookmore natural, stones should be buriedat a depth of about one quarter oftheir height.Another option is adding organicmatter, such as shredded leaf mulch,to improve soil structure. It alsoconserves moisture, blocks light thatmany weed seeds need to germinate,lessens erosion, and is an attractivetop dressing for your planting bed.As a rule-of-thumb, apply mulch to adepth of 2-3 inches in planting beds.The depth of mulch to apply willdepend upon the type of material used.Be sure not to bury seedlings ordormant plants, and keep it a fewinches from the trunks of trees andshrubs. Commonly used organic mulchesinclude: chipped or shredded woodmulch, such as pine or cypress; pinneedles; and shredded leaves.Inorganic mulches include: gravel andother types of stone.Planting27

Figure 33. The drawing above illustrates how rain gardens and rain barrels work together to capture runoff. The downspout isdirected into a rain barrel to collect roof runoff. In order to collect more roof runoff, two rain barrels are connected to each other.The excess runoff will pour out through the rain barrel’s over-flow valve. You can attach an overflow hose to the valve to helpdirect flow towards your rain garden. By storing the stormwater runoff in rain barrels, you’ll be able to water your rain gardenduring dry periods.

MaintenanceBeforeGood design andregular maintenancewill continue to helpclean stormwater.AfterFigure 34. A Burnsville, MN home before and after rain garden construction. The City of Burnsville, MN constructedrain gardens to improve the water quality of Crystal Lake by adding rain gardens to a 20-year-old neighborhood. Tolearn more about the project visit http://www.landandwater.com/features/vol48no5/vol48no5_2.html.Give your rain garden TLC to ensure itfunctions properly. Tender loving caredoes not mean 24-7 maintenance, butby making adjustments when needed,you’ll be able to enjoy your gardenthroughout the seasons (figure 34). Inthis section you’ll learn how to maintainyour rain garden by measuring itsperformance over time andincorporating rain barrels into yourrain garden design.Rain barrelsWater your plants immediately. Theywill need about an inch of water perweek to become established. To helpregulate watering, incorporate rainbarrels into your rain garden design(figure 33). Simply connect your rainbarrel to the downspout draining toyour garden (figures 36 and 37 on page30). Direct the overflow hose intoyour garden so that excessive runoffwill flow from the hose into yourgarden. Whatever is left inside therain barrel can be used to water yourgarden in times of prolonged drought.Other rain barrel benefits include:MaintenanceLower water costs (a rain barrelcan save approximately 1,300gallons of water during peaksummer months).Beautifully designed rain barrelsif built with the propermaterials and tools (figure 35 onpage 30).Naturally rechargesgroundwater.Reduced water pollution byreducing stormwater runoff,which can contain pollutants likesediment, oil, grease, bacteria,and nutrients.29

Maintaining your rain barrel is easytoo. Keep these simple tips in mind fora properly functioning rain barrel.Figure 35. Rain barrel artwork.Clear debris away from the inlet ona regular basis to allow roof runoffto pour into the rain barrel.Unless your rain barrel canwithstand freezing temperatures,clean out your rain barrel at theend of the season and store itindoors to prevent water fromfreezing inside of it. Freezingtemperatures could damage yourrain barrel.Performance evaluationOnce you’ve constructed your raingarden you’ll need to maintain properdrainage and healthy plants. Considerthe following tips to maintain your raingarden’s performance.Rain garden performanceFigure 36. Highland Beach Town Hall rain barrels.Visual inspections offer the easiestway to evaluate your garden for properdrainage. After a storm ends, visuallyinspect the rain garden for standingwater at 24 and 48 hours. You’ll needabout an inch of rain or more. If thereis still standing water after 48 hours,you’ll need to make adjustments basedon your site’s conditions (refer topages 9 to 11). To verify properconstruction and ensure long-termperformance, check for the itemsbelow.Figure 37. Connected rain barrels at Arlington Echo.30 MaintenanceSediment accumulation in thebasin from the drainage areaClogged inlet or outletExcessive erosion within thegarden

Healthy native plantsYour native plants are the stars of thegarden. Take care of them by applyingthe tips below to evaluate the healthof your plants.Begin with a record of thegarden design showing the plantsinstalled and their location(refer to page 22).Record the time of growingseason and age of the garden.Describe the condition of thesite when you assess your plants.With the help of a plant fieldguide and your original gardendesign, identify the speciespresent and their growthrequirements. This will helpdetermine whether or not thecorrect species are present.Record the color, size, andquality of the leaves, stem, andflowers. Compare this to youroriginal garden design.Estimate the percentage ofvegetative cover to determine ifplants are established.Inspect your garden for wetlandplant species to determine ifhydric soils may be present,indicating prolonged periods ofsaturation.Take pictures of your garden todevelop a complete record ofconditions at the time of yourassessment.During a growing season, recordobservations as needed. Followthese tips annually so that you’llhave records to compare growingseasons and note any changes.ESD Criteria # 20. MaintenanceRain garden maintenance isgenerally no different than thatrequired of other landscapedareas.The top few inches of theplanting soil should be removedand replaced when water pondsfor more than 48 hours. Siltsand sediment should be removedfrom the surface of the bed asneeded.Where practices are used totreat areas with higherconcentrations of heavy metals(e.g., parking lots, roads), mulchshould be replaced annually.Otherwise, the top two to threeinches should be replaced asnecessary.Occasional pruning andreplacement of dead vegetationis necessary. If specific plantsare not surviving, moreappropriate species should beused. Watering may be requiredduring prolonged dry periods.Rain gardens shall have amaintenance plan and beprotected by an easement, deedrestriction, ordinance, or otherlegal measures preventing itsneglect, adverse alteration andremoval.Your contributionEach rain garden you build cleans ourwaterways so that one day we’ll say inthe watershed of the Chesapeake andCoastal Bays, “What falls on site, stayson site”. -www.RainScaping.orgMaintenance31

Rain Garden ChecklistNo. Task Page1. Locate your rain garden site. 5-62. Decide the best shape for your garden. 7, 19-203. Estimate its drainage area. 11-124. Figure out its surface ponding depth. 12-135. Determine your rain garden’s area. 13-146. Sketch out your garden’s dimensions. 15, 17, 237. Contact Miss Utility 1-800-257-7777. 178. Figure out your budget. 179. Make sure your garden catches the runoffyou’re planning to treat.1910. Build a berm. 20-2111. Dig your rain garden. 2112. Consider adding rain garden soil mixture,mulch, or stones (optional).6-7, 20,21, 2713. Buy native plants. 24-25,38-4314. Lay out and plant the rain garden design.Remember to cluster, cluster, and cluster!15. Incorporate a rain barrel into your gardenlayout.16. Evaluate your rain garden for properdrainage and healthy plants.17. Review environmental site design criteriatips 1-20 to meet Maryland’s stormwatermanagemet criteria.23-27, 3729-3030-31ii, 1, 2-3,5-6, 9, 12,17-18, 21,23, 26, 3132 Rain Garden Checklist

Appendix A:Soil testsAppendicesAppendix B:Rainfall depthby the Maryland Departmentof the Environment.Maryland Stormwater Design Manual,“Unified Stormwater Sizing Criteria”Appendix C:Rain garden templatesby Low Impact Development CenterAppendix D:Native plantsby Maryland Cooperative ExtensionSwamp SunflowerAppendices33

Soil testsFigure 38. Dig a hole first. Figure 39. Fill the hole with water. Figure 40. Lastly, track time.The percolation test and the clay testcan help you identify soil type in yourrain garden area.Percolation TestThere are two percolation tests thatcan help you determine how fast waterdrains in your soil.1. Water in a holeDig a hole about 1-2 feet wideand 2 feet deep at the raingarden site (figure 38).Fill the hole with water(figure 39).If the hole drains in less than24 hours, your soil is probablysuitable for a rain garden(figure 40).If there’s water in the holeafter 24 hours select anothersite or talk to a professionallandscaper.2. Water in a can Remove the ends from a 46-ounce can or a large can of juice. Insert the can two inches intothe ground. Pour a quart of water into thecan. Depending on how many minutesit takes for the water to drain,you may or may not have suitablesoils for a rain garden (table 4).Drainage Time Soil Porosity Drainage ConditionsLess than 4minutesExcellent percolationsand air circulation.This soil offers the best drainage conditionsfor planting a rain garden.4 to 10 minutes Somewhat compact ordense soil.Acceptable drainage for a rain garden butslower; may need to aerate or augment soil.Over 10 minutesTable 4. Drainage time.Overly compact or dense. Very poor drainage; challenging conditions.Must augment soil, mill, and aerate.34 Appendix A

Clay-sandy soils testSoils with high clay content mayprevent proper drainage. Sandy soilsare the best soils for drainage. You canuse the tests below to identify soiltype or contact your local NaturalResources Conservation Serviceextension office for assistance.1. Clay ribbonThe simplest way to test for clayor sandy soils (and at no cost) isto dampen a handful of soil inyour hands (figure 41).Knead the soil into a ball(figure 42).Roll the ball between your handsto make a rope of soil uniformlythick (figure 43).Allow the rope to extendunsupported over yourforefinger until it breaks fromits own weight.If the rope extends unsupportedgreater than an inch before itbreaks, and feels more smooththan gritty, the soil may havetoo much clay in it. This site maybe unsuitable for a rain garden.Select another site or talk to aprofessional landscaper.2. Soil mapsSoil maps are a good referencefor a basic understanding of thesoils in your neighborhood. Theywill tell you what soils are on andnear the land.Your local Natural ResourcesConservation Service extensionoffice will have soil maps foryour area.Figure 41. Dampen a handful of soil in your hands andknead the soil. Clay soil, when compacted, can preventdrainage. Sandy soil feels gritty and may be moredifficult to knead, crumbling in the palm of your hands.Figure 42. Knead the soil into a ball about an inch indiameter.Figure 43. Roll the ball between your hands to make arope of soil uniformly thick. If your rope breaks beforeextending an inch then you probably have sandy soilsthat allow proper drainage. This site may be suitablefor your rain garden.Appendix A35

Rainfall Depth ChartCountyRainfall Depth (inches)1 yr - 24 hr 2 yr - 24 hr 10 yr - 24 hr 100 yr - 24 hrAllegany 2.4 2.9 4.5 6.2Anne Arundel 2.7 3.3 5.2 7.4Baltimore 2.6 3.2 5.1 7.1Calvert 2.8 3.4 5.3 7.6Caroline 2.8 3.4 5.3 7.6Carroll 2.5 3.1 5.0 7.1Cecil 2.7 3.3 5.1 7.3Charles 2.7 3.3 5.3 7.5Dorchester 2.8 3.4 5.4 7.8Frederick 2.5 3.1 5.0 7.0Garrett 2.4 2.8 4.3 5.9Harford 2.6 3.2 5.1 7.2Howard 2.6 3.2 5.1 7.2Kent 2.7 3.3 5.2 7.4Montgomery 2.6 3.2 5.1 7.2Prince George’s 2.7 3.3 5.3 7.4Queen Anne’s 2.7 3.3 5.3 7.5St. Mary’s 2.8 3.4 5.4 7.7Somerset 2.9 3.5 5.6 8.1Talbot 2.8 3.4 5.3 7.6Washington 2.5 3.0 4.8 6.7Wicomico 2.9 3.5 5.6 7.9Worcester 3.0 3.6 5.6 8.1Table 5. Listed in the table above are rainfall depths associated with the 1, 2, 10 and 100-year, 24-hour stormevents (source: Chapter 2 of the Maryland Stormwater Design Manual, “Unified Stormwater Sizing Criteria”, page2.11) . Maryland’s environmental site design (ESD) sizing criteria for new development requiring stormwatermanagement states that ESD practices shall treat the runoff from one inch of rainfall. However, if your water qualitygoal is to treat 100% of the runoff from a 1 year, 24-hour storm event, use the rainfall depth chart above todetermine how much rainfall you need to plan for. For instance, a Worcester County resident treating 100% ofrunoff from the 1 year, 24-hour storm event needs to size their rain garden to treat the runoff from a three inchstorm event. Refer to page 15 to learn more about sizing your rain garden based on targeting a rainfall amount.36 Appendix B

Rain garden templateNote: The number of plants for each designated area is approximate.Butterfly SwaleLow Maintenance, 250 SF, Coastal Plain, Full SunA - 10 Chelone glabra (White turtlehead)B - 13 Verbena hastate (Blue Vervain)C - 10 Amsonia tabernaemontana (Blue-star flower)D - 12 Lobelia cardinalis (Cardinal Flower)E - 13 Amsonia hubrechtii (Narrow-leaf Blue-Star flower)F - 12 Muhlenbergia capillaries (Pink Muhly Grass)G - 52 Carex stricta (Tussock sedge)H - 1 Magnolia virginiana (Sweetbay)I - 16 Aster novi-belgii, ‘Professor Anton Kippenburg’ (New York Aster)J - 7 Chelone lyonii (Pink Turtlehead)Butterfly Swale,Low Maintenance, 250 SF, Coastal Plain, Pt Shade/ShadeA - 10 Myosotis scorpioides (Forget-me-not) or Mertensia virginiana (Virginiabluebell)B - 13 Gentiana andrewsii (Bottle Gentian) or Aster cordifolius (Blue Wood Aster)C - 10 Amsonia tabernaemontana (Blue-star flower)D - 12 Lobelia siphilitica (Great Blue Lobelia)E - 13 Phlox divaricata (Woodland Phlox)F - 12 Aruncus dioicus (Goatsbeard)G - 32 Elymus hystrix (Bottlebrush Grass) or Ajuga reptans (Carpetbugle)H - 1 Aesculus parviflora (Bottlebrush buckeye)I - 16 Aster cordifolius (Blue Wood Aster) or Tradescantia virginiana(Spiderwort)J - 7 Viola papilionacea (Common Blue Violet) or Dicentra eximia (Hardy BleedingHeart)Appendix C37

Native plantsJacob’s LadderLyre-leaf SageWhether you live in the coastal plain,piedmont, or mountain regions of theChesapeake and Atlantic Coastal BaysWatersheds, the native plants youselect will provide many benefits toyour rain garden and the environment.Native plant benefits include:Resilient to insects and disease,and are less likely to needpesticidesBest adapted to local conditions,e.g., no need to use chemicalfertilizersConserving water , i.e., onceplants are established in theright place, no need forsupplemental wateringHigh habitat value providesfood, shelter, and nesting areasfor wildlifeBy growing native trees and shrubs youwill also improve air quality and saveenergy. Trees and shrubs can removecarbon dioxide (CO 2 ) from theatmosphere during photosynthesis toform carbohydrates that are used inplant structure/function and returnoxygen back to the atmosphere as abyproduct. About half of thegreenhouse effect is caused by CO 2 .Trees also reduce the greenhouseeffect by shading our homes andoffice buildings, lowering the cost ofair conditioning during the summer.Beebalm38 Appendix DThis section lists a few native ferns,grasses, sedges, flowers, shrubs, andtrees adaptable to the coastal plain,piedmont, or mountain regions.

The key following will help you identifywhich native plants are suitable foryour rain garden based on sunlightexposure, its soil moisture content,color, height, and bloom time. Foradditional native plants, refer toNative Plants for Wildlife Habitat andConservation Landscaping: ChesapeakeBay Watershed.SunlightFull sun (Su) receives directsunlight for at least six hours aday during the growing season.Partial shade (PS) receivesapproximately three to six hoursof direct sunlight during thegrowing season.Shade (Sh) receives less thanthree hours of direct sunlight orfiltered light.Soil MoistureMoist (M) areas are where thesoil is saturated for much of theFlower colorsThe key below is a simplified list ofcolors and includes all shades.Bl=blueB=brownG=greengrowing season, except indroughts. These plants canhandle saturated areas longer.Average (A) areas are wherethe soil is damp, and may beoccasionally saturated. Plantscan handle saturated and drysoils.Dry (D) areas are where waterdoes not remain after a rain.These areas may be in full sun orin a windy location, on a steepslope, or have sandy soil. Plantsin this category are droughttolerant.O=orangeP=pinkPu=purpleR=redW=whiteY=yellowFernsCinnamon FernRoyal FernSensitive FernCommon Name Scientific Name M A D Su PS Sh HeightCinnamon Fern Osmunda cinnamomea X X X X X 2-5’Maidenhair Fern Adiantum pedatum X X X 1-2’Northern Lady Fern Athyrium filix-femina X X X 1-3’Royal Fern Osmunda regalis X X X X X 1.5-6’Sensitive Fern Onoclea sensibilis X X X X X 1-3.5’Appendix D39

Grasses and sedgesBroomsedgeSwitchgrassTussock SedgeCommon Name Scientific Name M A D Su PS Sh HeightBroomsedge Andropogon virginicus X X X X 1-3’Switch Grass Panicum Virgatum X X X X X 3-6’Tussock Sedge Carex stricta X X X 1-3.5’HerbaceousWild GingerCommonNameGreat Blue LobeliaSmooth Solomon’s SealScientific Name M A D Su PS Sh Height Color BloomBeebalm Monarda didyma X X X X 2-5’ R, Pu Jul-AugBlueflag Iris Iris versicolor X X X X 3’ Bl, Pu May-JunGinger, WildAsarumcanadenseX X X X 0.5-1’ B, Pu Apr-MayCardinal Flower Lobelia cardinalis X X X X 2-4’ R Jul-SeptCommonbonesetFoamflowerEupatoriumperfoliatumTiarellacordifoliaX X X X X 1-5’ W Jul-SeptX X X 0.5-1’ W Apr-JulGoldenrod,Wrinkled-leafGreat BlueLobeliaSolidago rugosa X X X X 1-6.5’ Y Sept-OctLobelia siphilitica X X X X 2-3’ Bl Aug-OctJacob’s Ladder PolemoniumreptansX X X X 0.5-1.5’ Bl Apr-Aug40 Appendix D

Herbaceous cont.Common Name Scientific Name M A D Su PS Sh Height Color BloomJoe Pye WeedEupatoriumfistulosumX X X X X 1.5-10’ P Jul-SeptLyre-leaf Sage Salvia lyrata X X X X X 1-2’ Pu Apr-JunMarsh Marigold Caltha palustris X X X 1-2’ Y Apr-JunMeadow Phlox Phlox maculata X X X X X 1-3’ P, Pu May-SeptMist FlowerNarrow-LeavedMountain MintNew YorkIronweedObedient PlantRose MallowSmoothSolomon’s SealSpiderwortConocliniumcoelestinumPycnanthemumtenuifoliumVernonianoveboracensisPhysostegiavirginianaHibiscusmosheutosPolygonatumbiflorumTradescantiavirginianaX X X X X X 1-3.5’ Pu Jul-OctX X X X X 1.5-2.5’ Pu, W Jul-SeptX X X X 3.5-8’ Pu Aug-OctX X X X X 1.5-5’ P, Pu Jun-SeptX X X X 3-6’ P, W Jul-SeptX X X X X 1-3.5’ Y Apr-JunX X X X 1-3’ B, Pu Apr-JulSummer Phlox Phlox paniculata X X X 1.5-6.5’ P, Pu Jul-OctSwampMilkweedSwampSunflowerTall WhiteBeardtongueAsclepiasincarnataHelianthusangustifoliusPenstemondigitalisX X X X 4-6’ P, W May-JunX X X 1.5-5.5’ Y Aug-OctX X X X X 2-5’ W Apr-JunTurtlehead Chelone glabra X X X X 1-3’ W, P Aug-OctWoodland Phlox Phlox divaricata X X X 1.5’ Bl, W Apr-JunNew York IronweedAppendix DObedient PlantWoodland Phlox41

ShrubsMountain LaurelCommonNameRed ChokeberrySourthern ArrowwoodScientific Name M A D Su PS Sh Height Color BloomAmericanBeautyberryBlackChokeberryButtonbushElderberryHighbushBlueberryCallicarpaamericanaPhotiniamelanocarpaCephalanthusoccidentalisSambucuscanadensisVacciniumcorymbosumX X X X X 6’ Pu Jun-AugX X X X X 3-6’ W Apr-MayX X X X X 5-12’ W, P Jun-SeptX X X X X X 6-12’ W May-JunX X X X X 6-12’ P May-JunInkberry Ilex glabra X X X X X X 6-10’ W May-JulMountainLaurelKalmia latifolia X X X X X X 12-20’ W, P Jun-JulNorthernBayberryPink AzaleaMorellapensylvanicaRhododendronpericlymenoidesX X X X X 5-10’ Y Mar-AprX X X X X X 3-10’ P, W Apr-MayRedChokeberrySilkyDogwoodPhotinia pyrifolia X X X X X 1.5’-13’ W Mar-MayCornus amomum X X X X 6’-12’ W Mar-AprSouthernArrowwoodViburnumdentatumX X X X X X 10-15’ W, P Apr-MaySpicebush Lindera benzoin X X X X 6.5-16’ W, Y Mar-May42 Appendix D

CommonNameShrubs cont.Scientific Name M A D Su PS Sh Height Color BloomSwamp AzaleaRhododendronviscosumX X X X 6.5-10’ W, P May-AugSweet PepperBushVirginiaSweetspireClethra alnifolia X X X X 6-12’ W Jul-AugItea virginica X X X X X X 6-10’ W Apr-JunWax Myrtle Myrica cerifera X X X X X 6-15’ G Mar-AprWinterberry Ilex verticillata X X X X X 6-12’ W, Y,G, BApr-JulWitherod Viburnum nudum X X X X X 6.5-20’ W Jun-JulTreesWhite Fringetree Sweetbay Magnolia Red MapleCommon Name Scientific Name M A D Su PS Sh HeightAmerican Holly Ilex opaca X X X X X 15-50’Black Gum Nyssa sylvatica X X X X X 30-75’Fringetree, White Chionanthus virginicus X X X 20-35’Red Maple Acer rubrum X X X X 40-100’River Birch Betula nigra X X X X 50-75’Serviceberry/Shadbush Amelanchier canadensis X X X X 35’-50’Swamp White Oak Quercus bicolor X X X 60-100’Sweetbay Magnolia Magnolia virginiana X X X X X 12-30’Willow Oak Quercus phellos X X X X 80-100’Appendix D43

ReferencesAseleson, Brooke C., Rebecca S. Nestingen, John S. Gulliver, Raymond M. Hozalski, and John L. Nieber, 2009. PerformanceAssessment of Rain Gardens. Journal of the American Water Resources Association (JAWRA) 45(4):1019-1031.10.1111/j.1752-1688.2009.00344.x.Central Ohio Rain Garden Initiative. 2009. Columbus, Ohio. Available online at http://www.centralohioraingardens.org.Accessed October 28, 2009.Chesapeake Bay Foundation. No date. Build Your Own Rain Garden. Annapolis, Maryland. Available online at http://www.cbf.org/site/PageServer?pagename=exp_sub_resources_publications. Accessed May 15, 2008.City of Tallahassee. No date. Rain Gardens: A How-to Manual for Homeowners. Tallahassee, Florida. Available online athttp://www.tappwater.org/what-raingardens.aspx?a=viewPost&PostID=2243. Accessed May 15, 2008.Environmental Protection Agency Office of Research and Development, National Risk Management Research Laboratory.September 2008. “Green Infrastructure Research Program”. Science Brief.Lexington Fayette Urban County Government. 2007. Rain Gardens. Brochure. Lexington: CDP Engineers, Inc. Available onlineat www.dca.ky.gov/NR/rdonlyres/69A3C57d-3984-4BA4-BA9B-CC8B90352C0C/0/LFUCG2007rainGardenBrochureFinal.pdf. Accessed May 16, 2008.Low Impact Development Center. Rain Garden Design Templates. Available online at http://www.lowimpactdevelopment.org/raingarden_design/templates.htm. Accessed May 22, 2008.Maryland Cooperative Extension, University of Maryland. 2005. Native Plants of Maryland: What, When and Where. CollegePark, Maryland. Available online at www.hgic.umd.edu. Accessed May 30, 2008.Maryland Stormwater Design Manual. Maryland Department of the Environment. 2000. Available athttp://www.mde.state.md.us/Programs/WaterPrograms/SedimentandStormwater/Mill Creek Watershed Council of Communities. 2007. What is a Rain Garden. Cincinnati: CDP Engineers, Inc. Available onlineat http://www.millcreekwatershed.org/rain-gardens.html. Accessed May 16, 2008.Rain Gardens of West Michigan and West Michigan Environmental Action Council. Copyright 2000-2008. Create a RainGarden. Grand Rapids, Michigan. Available online at http://www.raingardens.org/Create_A_Garden.php. AccessedMay 15, 2008.Rain Garden Network. Chicago, IL. Available online at http://www.raingardennetwork.com/. Accessed October 28, 2009.Rainscaping Campaign. National Fish and Wildlife Foundation. Funded by the 2009 Chesapeake Bay Small Watershed GrantsProgram. Available online at www.Rainscaping.org. Accessed October 27, 2009.Seymour, Rose Mary. Copyright 2008. Reclaim Your Rain: Rain Gardens for Home Landscapes. Duluth, Georgia. Availableonline at http://www.duluth-ga.com/dt/public_works/stormwater/stormwtrmgmt.html. Accessed May 15, 2008.______. No date. Build Your Own Rain Garden. Duluth, Georgia. PowerPoint presentation. Available online at http://www.accstormwater.com/publicinfo/Build_a_Rain_Garden.pdf. Accessed May 15, 2008.Slattery, Britt E., Kathryn Reshetiloff and Susan M. Zwicker. 2003. Native Plants for Wildlife Habitat and ConservationLandscaping: Chesapeake Bay Watershed. U.S. Fish & Wildlife Service, Chesapeake Bay Field Office, Annapolis,MD.South River Federation and the Center for Watershed Protection. October, 2002. How to Install a Rain Garden.Edgewater, Maryland. Available online at http://www.cwp.org/. Accessed May 15, 2008.United States Department of Agriculture Natural Resources Conservation Service. Plants Database. http://plants.usda.gov/. Accessed October 28, 2009.Wisconsin Department of Natural Resources and the University of Wisconsin-Extension Environmental Resources Center.2003. Rain Gardens: A how-to manual for homeowners. Madison: University of Wisconsin-Extension offices,Cooperative Extension Publications. UWEX Publication GWQ037 1-06-03-5M-100-S and DNR publication PUB-WT-776 2003.44

Worcester County Commissioners:Bud Church, PresidentLinda Busick, Vice-PresidentJudy BoggsRobert Lee Cowger, Jr.Louise GulyasJames L. PurnellVirgil ShockleyAuthors:Sandy Coyman, Worcester County*Keota Silaphone, Worcester CountyEditors:Mike Fritz, Environmental Protection AgencyJames Garrity, Worcester County*Christy Hallman, Worcester County*Zora Lathan, Chesapeake Ecology CenterKatherine Munson, Worcester CountyDavid Wilson, Maryland Coastal Bays ProgramPhyllis Wimbrow, Worcester County*no longer affiliated with Worcester CountyImage credits:Front cover—Cardinal flower image courtesy ofWilliam C. Miller lll, The Azalea Works.Page iv—Rain garden cycle drawing courtesy ofMarge Coyman based on Rice CreekWatershed District and Emmons &Oliver, Inc.Page 1—Rain garden in the landscape drawingcourtesy of Marge Coyman.Page 2—Stormwater runoff drawing courtesy ofKeota Silaphone based on stormwatergraphic design at www.RainScaping.org.Page 3—Highland Beach rain garden photos andshade rain garden at the ChesapeakeEcology Center courtesy of Zora Lathan.Page 4—Aerial imagery diagram courtesy of ErinRoss and Marge Coyman.Page 5—Rain garden sign photo courtesy ofKeota Silaphone.Page 6—Aerial imagery diagram courtesy ofKeota Silaphone and Marge Coyman.Page 7—Rain garden area drawing courtesy ofKeota Silaphone and Marge Coyman.Page 8—Rain garden depth drawing courtesy ofAcknowledgementsMarge Coyman based on an illustrationby Doug Adamson, Southview Design.Page 9—Aerial imagery diagram courtesy ofKeota Silaphone and Marge Coyman.Page 10—Permeable pavers at Back CreekNature Park in Annapolis, MD. Photocourtesy of Zora Lathan.Page 11—Aerial imagery diagram courtesy ofKeota Silaphone and Marge Coyman. Roofphoto courtesy of Keota Silaphone.Page 13—Slope sketch courtesy of KeotaSilaphone and Marge Coyman.Page 15—Graphic drawing courtesy of JimmyGarrity and Marge Coyman.Page 17—Rain garden profile courtesy of KeotaSilaphone and Marge Coyman.Page 18—Bay-Wise master gardeners building arain garden photo courtesy of ZoraLathan.Page 19—Curb cut image courtesy of the City ofBurnsville, MN. Rain garden installed atHeritage Baptist Church in Annapolis,MD photo courtesy of Zora Lathan.Page 20—The Maryland Lower Eastern ShoreTributary Team marking the gardenedge photo courtesy of Jimmy Garrity.Reusing the garden area’s sod photocourtesy of Christy Hallman.Page 21—Leveling image courtesy of IowaNatural Resources Conservation Service.Page 22—Rain garden template drawing courtesyof Erin Ross and Marge Coyman.Spiderwort, Blue iris, and Tall whitebeardtongue photos courtesy of KeotaSilaphone. Blueberry bush photocourtesy of L. Michael Adams. Thefollowing images were downloaded fromwww. Wildflower.org: Marsh marigoldimage courtesy of Doug Sherman andSwamp milkweed image courtesy of Sallyand Andy Wasowski.Page 23—Rain garden template drawing courtesyof Keota Silaphone and Marge Coyman.Page 24—Lincoln Drive rain garden photocourtesy of Cindy Wallace.Page 25—White turtlehead image courtesy ofU.S. Forest Service. Baltimore45

Acknowledgements cont.Checkerspot Butterfly image courtesyof Wikimedia Commons.Page 26—Rain garden planting at the ProvidencePresbyterian Church in Salisbury,Maryland. Photo courtesy of KeotaSilaphone.Page 27—Rain garden photo courtesy of KaraBowne Crissey.Page 28—Rain barrel and rain garden artworkcourtesy of Keota Silaphone.Page 29—Before and after rain garden imagescourtesy of the City of Burnsville, MN.Page 30—Highland Beach town hall rain barrelsand Arlington Echo rain barrel photoscourtesy of Zora Lathan. Rain barrel artimage courtesy of Sheree ofwww.watercolorplus.com.Page 33—Soil photo courtesy of the WorcesterCounty Department of Public Works andKeota Silaphone. Average yearlyprecipitation image courtesy ofwww.WorldBook.com. Rain gardendrawing courtesy of Erin Ross and MargeCoyman. Swamp sunflower imagecourtesy of Sally and Andy Wasowski,www Wildflower.org.Page 34—Soil test photos courtesy of theWorcester County Department of PublicWorks and Keota Silaphone.Page 35—Soil test photos courtesy of theWorcester County Department of PublicWorks and Keota Silaphone.Page 37—Rain garden template courtesy of LowImpact Development Center.Page 38—Jacob’s Ladder image courtesy ofStefan Bloodworth, www.Wildflower.org.Lyre-leaf Sage image courtesy ofNorman G. Flaigg, www.Wildflower.org.Beebalm image courtesy of ThomasBarnes of the University of Kentucky.Page 39—Cinnamon fern image courtesy ofwww.RainScaping.org. Royal fern andsensitive fern images courtesy of Sallyand Andy Wasowski,www.Wildflower.org.Page40—Broomsedge image courtesy ofWildflower Center staff. Switchgrassphoto courtesy of Zora Lathan. TussockSedge image courtesy of NRCS-USDA.The following images were downloadedfrom www. Wildflower.org: Wild gingerimage courtesy of Doug Sherman, Greatblue lobelia image courtesy of StefanBloodworth, and Smooth solomon’s sealimage courtesy of Norman G. Flaigg.Page 41—New York ironweed image courtesy ofStefan Bloodworth, www Wildflower.org.Obedient plant photo courtesy of KeotaSilaphone. Woodland phlox imagecourtesy of Mrs. W.D. Bransford,www.Wildflower.org.Page 42—Mountain laurel, red chokeberry, andsouthern arrowwood photo courtesy ofKeota Silaphone.Page 43—White Fringtree photo courtesy ofSpencer Rowe. Sweetbay magnolia imagecourtesy of Sally and Andy Wasowski,www.Wildflower.org. Red maple imagecourtesy of www.RainScaping.org.Back cover—Cardinal flower image courtesy ofWilliam C. Miller lll, The Azalea Works.Revised & printed January 2010.Originally printed September 2008.46

Special ThanksRain Gardens Across Maryland is based on original contentfrom Rain Gardens—A How-To Manual for Homeownersdeveloped by the Wisconsin Department of NaturalResources and the University of Wisconsin-Extension andRain Gardens in Maryland’s Coastal Plain developed by theWorcester County Department of Comprehensive Planning.This project was funded by the Maryland Coastal BaysProgram, the RainScaping Campaign, and Arlington EchoOutdoor Education Center.For more information, contact the Worcester CountyDepartment of Development Review and Permitting at(410) 632-1200, 1 West Market Street, room 1200, SnowHill, Maryland 21863. Additional copies of Rain GardensAcross Maryland can be downloaded fromwww.co.worcester.md.us, www.mdcoastalbays.org,www.arlingtonecho.org, www.aacountywatershedstewards.org,and www.RainScaping.org.The original hardcopy document has been printed by Delmarva Printing, Salisbury, Maryland.47

Final thought“Don’t stress too much over it. The raingarden does not have to be perfect to doits job, and it will change over time—that’s one of the things that makes it sorewarding; it’s a living, dynamic system.Dig a hole, relax, and let nature take itscourse. Observe and have fun”.-Spencer Rowe, Wetland ScientistJune 1, 2008