Roadside Revegetation

IMPLEMENTATION GUIDES
Restoration sites pose interesting challenges when evaluating limiting
factors. Road construction or decommission typically creates compacted
soils that have been severely altered in texture, stability, nutrient status,
and so on from their natural state.
Tasks
Determine plant needs
Plant Production
Road Construction
Plant
In addition to challenging physical soil characteristics, the biological
component of roadside planting sites has been severely altered or even
destroyed. A variety of mitigating measures may be necessary prior to
outplanting. Beneficial soil microorganisms, such as mycorrhizal fungi
and nitrogen-fixing bacteria, provide their host plants with many benefits
including better water and mineral nutrient uptake. Plants destined for
these sites should be inoculated with the appropriate symbiont before
outplanting (see Section 10.1.7, Beneficial Soil Microorganisms, for a
complete discussion).
Develop Timelines
Obtain “starter” plant materials
Develop and award contract
Work with nursery
Develop planting plan
Store plants
Transport plants to site
Obtaining some nursery stocktypes can take a considerable amount of
lead time and planning. Although most native plant nurseries carry a wide
variety of species, it is unlikely they would have plants that are genetically suitable for a specific
project. Therefore, “source-identified” native plants must usually be grown by contract. The
large nursery stocktypes that will survive and grow on challenging restoration sites typically
require several years (Figure 10-76). It is therefore necessary to develop contracts that will
assure that the correct genetic material is being propagated and that the resulting plants
are of the highest quality that will survive and grow when planted on the revegetation site.
Project plant needs are determined early in the revegetation planning stages, including the
number of plants, types of species, and size of plants. From the list of species, seed sources
or “starter” plant material sources are located from suppliers or collected in the wild. This can
typically take at least a year. Several years before the construction site is ready for planting, a
contract for growing plants is developed and awarded. Once awarded, seeds and “starter” plant
materials are sent to the nursery so that sowing, transplanting, or sticking can begin promptly.
The growing time for large container stock can extend from 1 to 2 years, depending on the
species. The nursery will take a final seedling inventory during the middle of the final growing
season. At this time, a planting plan can be developed. Road construction will be moving into
its final stage and the planting plan can be tailored to specific on-site conditions. Including
lifting, storage, and transporting plant materials, the whole process, from start to finish, takes
two to three years.
-3 -2 -1 0 1
Year
Figure 10-76 | Engage nurseries
early for plant materials
Obtaining nursery-grown plants often
requires two to three years of advance
planning. This timeline can be shorted
by up to a year if “starter” plant materials,
like willow cuttings or seedlings for
transplanting, are available. Certain
woody plants require long seed treatments
or grow slowly so timetables must
be adjusted accordingly.
Determine Plant Needs
Early in the planning stages, a general idea of plant needs is developed based on the desired
future condition for each revegetation unit. The information required to determine the
quantities for each revegetation unit includes:
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Area to plant
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Plant spacing (density)
◾◾
Survival potential
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Species mix
Using calculations similar to those presented in Figure 10-77, an estimate of the number of
seedlings to order from nurseries can be determined. Calculations should be performed for
each revegetation unit, since species mix, plant spacing, and survival will change considerably
between units.
Roadside Revegetation: An Integrated Approach to Establishing Native Plants and Pollinator Habitat
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