A Rain Garden - MSD

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A Rain Garden - MSD

SIMPLE STEPSFOR ASUCCESSFULRAIN GARDEN:1. UnderstandSTORMWATER2. Find the bestLOCATION3. Evaluate yourSOIL4. PLAN therain garden5. DESIGN the layout6. CHOOSE the plants7. PREPAREand PLANTthe garden bed8. MAINTAINyour garden` The plant at right isCommon milkweed.Monarch butterfliesneed this plant foodsource to support theirannual migration.A Rain Garden:Captures stormwater runoff.`~`a`~`Helps keep water clean by filtering stormwaterrunoff before it reaches our local streams.`~`a`~`Enhances the beauty of your yard and neighborhood.`~`a`~`Alleviates flooding and drainage problems.`~`a`~`Supports biodiversity by attracting birds and butterflies.`~`a`~`Helps replenish the ground water supply.`~`a`~`Reduces the need to mow.What about mosquitoes?A properly constructed Rain Garden isn’t a breedingground for mosquitoes. Rain Gardens are meant to drainquickly – usually within several hours after a “normal”rainfall. Even with a heavy rainfall, runoff will infiltratethe ground within a day. Mosquitoes need at least aweek of standing water to complete their life cycle.The Culex mosquito, the primary transmitter for severaldiseases including West Nile Virus, breeds in stagnantwater. Poorly maintained birdbaths, gutters and saucersunder planters serve as ideal mosquito breeding grounds.4 54` TOP: Butterfly Milkweed


` Water runoff fromroofs diverted intoRain Gardens andRain Barrels preventstormwater andpollutants fromreaching stormdrains, and eventuallyour streams and rivers.RAIN GARDENSSTORM DRAINRAIN BARREL` Most of the BeargrassCreek Watershed —including downtownLouisville, St. Matthews,Buechel and Newburg— has more than 30%impervious (hard) surface.Stormwater runoff from allthe hard surfaces in oururban community putsa tremendous burden onour aging infrastructureand stresses the watershedenvironment.1.Understanding StormwaterIt doesn’t take much of a rain event to trigger stormwater runoff.Most of the pollutants we find in the water of our local streams arrivewith the first flush of a substantial rain. Few of us realize what animpact a rain garden could make in soaking up (infiltrating) this water.An average roof of a 30' X 50' smallhouse equals 1,500 square feet. Coverthat square footage with one inch ofrain water and the roof has quicklygenerated a volume of 935 gallons ofwater – or the amount required to fill16 rain barrels! Even a small rain gardencan manage a lot of runoff from adisconnected down spout.Strategically placed rain gardens cankeep runoff from hard surfaces suchas driveways, sidewalks or patios fromever reaching a local stream. Each siteis different, and requires thought and ` Water redirected from the roofinvestigation. The best time to analyzegutter now flows into this Rain Gardenat The Louisville Nature Centerthe specifics of your stormwater runoffis when it’s raining. So, grab an umbrella,go outside and observe where the water is draining.Asking yourself some questions before you begin to construct your raingarden will help to avoid unforeseen problems. How does the waterflow through your yard? Are there places where the runoff is causingerosion along the edge of a patio or driveway? These are things you willwant to consider as you proceed with the design of your rain garden.67


How a Rain Garden worksRain gardens aredesigned to collectrainwater from theroof. The redirectedflow is absorbed byplants and infiltratesinto the ground.Choose plants that arenative, drought tolerantand non-invasive.A berm helpscontain waterduring heavyrains.The deep, dense roots of native plants helpbreak up heavy soils and increase infiltration.Common grass seed mixtures, used in lawns,have very shallow roots and as a result,cannot absorb excess water.2.Finding the best LocationRain gardens are not only functional,they are beautiful. Of course, there arepractical considerations in locatingyour rain garden, but it should alsobe situated where it can be enjoyed!One accepted rule of thumb is to place your garden 10' or more fromthe house foundation to avoid any possibility of water seepage into thebasement. The garden should be located close enough to the source ofwater runoff — your disconnected downspout or driveway — so thatwater can easily be directed into the garden bed. The distance from theend of the downspout can be extended by adding a length of 4 inch PVCor black plastic drain pipe to the edge or center of the garden.It is important to place your rain garden in an area that does not tendto hold water. Wet areas of shallow water indicate slow percolationand heavy soils with no infiltration. A rain garden is not a pond nor awetland – it is designed to absorb water, and at the longest, shouldn’thave standing water for more than 24 hours.Locate your garden to capture runoff as it drains from the roof throughthe downspout. Many houses have four or more downspouts, eachtaking a percentage of the entire roof surface area. Walk around thehouse and observe what portion feeds the particular downspout thatwill empty into your garden. The more captured runoff, the more areaneeded for the garden. Capturing 100% of the roof runoff is sometimespossible but isn’t always realistic, especially if you have a tiny yard orhave a thin layer of soil before reaching bedrock.Choose an area for your rain garden that is almost flat or gently sloping.Avoid too steep of a slope as the steeper the slope, the more diggingnecessary to make the finished garden level. The more complicated thesite, the more technical assistance you may need.In addition to determining where the runoff will enter your garden, bemindful of where the water could possibly overflow in the event of asevere storm. You don’t want to send water in an unwanted directionsuch as towards your neighbor!Full or partial sun works best, although rain gardens can also work inshady areas with careful plant selection. It’s not a good idea to placea rain garden under a large, mature tree where garden constructionmay damage tree roots. Small trees and shrubs can be successfullyincorporated into the rain garden design.8 9


3.Evaluating your Soil`Useful toolsto have orborrow:Garden tillerShovelRakeTrowelWheelbarrowGarden hose withspray nozzleLength of 4 inchPVC or black plasticdrain pipe,if needed,to direct downspoutwater to thegardenSoil texture determines how well water willsoak through, or infiltrate, the soil. Soil iscomposed of three mineral particles – sand,silt and clay (often referred to as “the texture”).When soil is made up of a high percentage ofclay, stormwater will not soak in. Rememberthat standing water indicates the soil is holdingwater and is probably not a good site for a raingarden.For a quick way to determine your soil’s texture,grab a small handful of moist soil. Beginpressing the soil between your thumb andindex finger to make a ribbon. Soil with a highclay content will form a ribbon longer than twoinches. Also, clay soil will stick together and belight in color.Dense, compacted soils or soils with high claycontent will need to be amended to ensureproper drainage. To improve water infiltration,mix in some sand and a lot of organic materialsuch as compost to increase the total volumeby 50%. If needed, you can have your soiltested by the Jefferson County ExtensionService (website: http://ces.ca.uky.edu/jefferson).10 ` Oakleaf Hydrangea` TOP: Penstemon11


RoofRoof5.Designing the layoutGreatPenstemon BlueLobeliaCommonMilkweedIllinoisButterfly BundleflowerMilkweedMistflowerRiver OatsIndian GrassBlack-eyed SusanMulched pathSmoothAsterJoe Pye WeedGiantSunflowerIronweedPurple Prairie CloverConeflowerDownspout pipe extensionNewEnglandAsterCoreopsisBundleflowerVervainBlazing StarNew England AsterSmooth AsterCommonMilkweedBottlebrush GrassMistflowerMistflowerButterflyMilkweedRiver OatsStart by creating a rough layout ofyour garden. Graph paper is useful fordesigning to scale. Depending on thelocation, you may want to place tallerplants in the back with medium andshort plants in front. If it is possible towalk around your entire rain garden,you might consider placing the tallestplants in the middle.How you arrange your plantsdetermines the design. Some peoplelike a more natural look modeled afterhow plants grow in nature. Others prefera more refined, or not so “wild” look,grouping flowers and grasses in masses.In any case, you can accomplish your preference by using native flowersand grasses, including small trees and shrubs if you choose. Non-nativeplants are also acceptable as long as they are not invasive.Plants survive best when their basic requirements are met. Someplants need a lot of sun for a longer period of time. Others prefer amore shaded environment. To be successful, do your homework andselect the right plant for the right placePlace a bird house or bird bath nearby to attract birds. Use rocks todefine boundaries or add garden ornaments in and around your raingarden. Depending on its size, you can design a path through it withstepping stones, small gravel or mulch.` This rain garden plan places taller plants in the center andis designed so there are plants in bloom throughout the season.Rain gardens can provide a unique aesthetic beauty to yourneighborhood. When locating the garden consider all views fromboth inside and outside your house. As with any garden they can bedesigned adjacent to a patio or right outside a dining area window —whatever best suits your yard.14 ` TOP: Coralberry15


6.Choosing your plantsNative plants connect us with our naturalheritage and celebrate our unique ecoregion.They attract an entire network ofcritters that support our local biodiversity.Many butterflies depend on native plantsto sustain them on their migration journey.Native plants have deep roots and onceestablished, require little maintenance.They have the ability to withstandextremes in weather and long periodsof drought.`Native Honeysuckle`Monarch butterfly on Milkweed`If you want to attract butterflies toyour rain garden, take an examplefrom the Jeffersontown ElementaryThird Grade Class who are activelyinvolved with the Monarch Watchprogram. The class planted Milkweedplants and by chance watched aMonarch butterfly lay eggs on one ofthe plants they had planted in theprevious fall.As with any plant, it is best to select natives from our local genotype.A purple coneflower from Oregon will not survive as well as a purpleconeflower from Kentucky because of differences in climate and soilconditions.There is growing public concern about invasive non-native plants. A“non-native” plant comes from somewhere else other than our regionalecosystem. “Invasive” plants are just that — they are impacting ournative habitats and parks at an alarming rate, resulting in homogenizedlandscapes that don’t support biodiversity. They frequently out-competethe native varieties and, once established, are difficult to remove. PurpleLoosestrife, Crown Vetch, Wintercreeper, English Ivy, and Burning Bush areseveral plants that are considered invasive, yet are commonly available atnurseries and home improvement stores.Non-native plants are acceptable if they are not invasive. There are plentyof non-native, non-invasive perennial species that do well in rain gardens.Hostas and oakleaf hydrangeas are examples of some of the easy-togrow,non-native plants suitable for your garden.The lists on the following pages identify some of the Kentucky nativeplants, shrubs and trees suitable for rain gardens.16`Columbine` TOP: Phlox17


COSTThe cost of any raingarden depends onhow much of thework you are doingyourself, the size ofthe garden, the sizeand quantity of plantsyou buy, how muchyour soil needs to beimproved, and theamount of materialsyou buy.On average, a raingarden will cost $2to $5 a square foot.Therefore, a 400square foot raingarden could costanywhere from $500to $2,000.During April andMay many localplant sales take place.Watch the newspaperfor notices. Also,neighborhoods,organizations suchas Wild Ones, andindividuals often holdplant swaps, whereyou can acquireplants for little or nocost.Fall is a good seasonto plant trees andshrubs. During LaborDay weekend manynurseries have salesto reduce stock.8.Maintaining your gardenJust like any garden, your rain garden will need some basic maintenanceto keep it healthy and functioning. Although mulching will help reduceweeds, some weeding will be required, especially in early spring beforethe plants have filled out. Weeds should be pulled when young, byhand. Labeling as you plant will make it easier to recognize the weedsfrom the young native plants.Mulching is an important part of garden maintenance. The mainpurposes of mulch are to keep the soil moist, prevent the soil surfacefrom developing a hard crust, and add nutrients to the soil as it breaksdown. Spreading 2 to 3 inches of double shredded hardwood or leafmulch before planting is recommended, clearing away a space for theplants. (Be sure to keep the mulch from touching the plant stems,avoiding mold or rot.) Both types of mulch add nutrients to the soil.The rain garden will require watering, especially during the first yearafter planting while young plants are developing roots. Once plants areestablished, watering will only be required during periods of extremedrought.Never spread or spray fertilizers too close to your rain garden as it mayincrease weed production. Plants that are not doing well may need tobe relocated or removed entirely from the garden. Every garden is aunique situation and requires tending until established.RAIN GARDENS ARE POPPING UP ALL OVER THE COMMUNITY.WATCH THE MSD WEBSITE FOR ANNOUNCEMENTS OF RAIN GARDENPRESENTATIONS AND WORKSHOPS. LOOK FOR NOTICES OF NATIVEPLANT SALES IN THE NEWSPAPER. ARRANGE FOR A SPEAKER TO COMEAND TALK TO YOUR NEXT NEIGHBORHOOD MEETING. RAIN GARDENSARE A BEAUTIFUL SOLUTION TO OUR STORMWATER MANAGEMENT.22 ` Black-eyed Susan` TOP: Dense Blazing Star23


A HOW-TO GUIDE FORBUILDING YOUR OWNRAIN GARDEN 2nd Edition© 2008 Louisville and Jefferson CountyMetropolitan Sewer District.700 West Liberty StreetLouisville, Kentucky 40203-1911502-587-0603www.msdlouky.orgAll rights reserved` Plants pictured:front cover, top: Illinois Bundleflowerbottom: Purple Coneflowerback cover, left: Oakleaf Hydrangearight: Bottlebrush BuckeyeProduced by Phyllis Croce for MSDThanks to the following for their contributionto the production of this manual:Margaret Shea, Dropseed NurseryKurt Mason, Natural ResourcesConservation ServiceDonna Michael, Jefferson CountyExtension ServiceRosanne Kruzich, RKX Consulting, Inc.Jefferson County Soil and WaterConservation DistrictWisconsin Department of NaturalResourcesDesign and illustration:Marilyn Motsch /Stellar DesignPhotography: Phyllis Croce, Jack Francisand Marilyn Motsch

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