Restoration Techniques

NOTE: For species that do not tolerate dry storage, seeds must be sowed directly outside after harvest, or stored in cold moist sphagnum until ready to sow. Most woodland species germinate better after a period of cold moist stratification, for example by sowing in November or December before snow fall.

Restoration Potential Rating

PROVEN PERFORMERS. Most of the species in this class produce abundant seed that is easy to collect, store, and germinate, and they have seedlings that grow quickly to produce flowering plants. Examples include American beakgrass (Diarrhena americana), hispid buttercup (Ranunculus hispidus), and zig zag goldenrod (Solidago flexicaulis). Species in this group may collective form a dense enough ground cover to deter the colonization of garlic mustard (Alliaria petiolata).

HIGH restoration potential. These species may be limited in the number of seeds produced, but have the capacity to establish and reproduce quickly through self-sowing and vegetative spread. Examples include James' sedge (Carex jamesii), Virginia waterleaf (Hydrophyllum virginianum) and wild ginger (Asarum canadense). We also recommend these species in the initial phase of a woodland restoration project if transplants can be obtained.

MEDIUM to LOW restoration potential. Many species are included in this category because seed must be kept moist if stored (and are subject to deterioration), seed availability is limited due to small populations and/or limited seed production per plant. Many are also slow growing, requiring several to many years to reach reproductive maturity. Many of these species can be successfully introduced as transplants obtained from native nurseries, although they do not have extensive vegetative spread. Examples include blue cohosh (Caullophylum thalictroides), large flowered bellwort (Uvularia grandiflora), Pennsylvania sedge (Carex pensylvanica), showy tick trefoil (Desmodium glutinosum), and spring beauty (Claytonia virginica). This category also includes species that have restricted habitat requirements. Examples include monkey flower (Mimulus ringens) and whorled milkweed (Asclepias verticillata).

AVOID! DO NOT INCLUDE IN A RESTORATION. Species in this category have the capacity to displace other species at the restoration site, and even become a near monoculture.

Note: These restoration categories are an estimate based on research, observation and experience. It is likely that they will vary with site conditions. For example, bloodroot (Sanguinaria canadensis) may self-sow readily in the absence of competing vegetation. Species may also change categories as new information about their performance at restoration sites becomes available.



Note: Never collect seeds or plants without landowner permission.

Proven performers are species that can be easily reintroduced by seed. These species produce abundant seeds that tolerate dry storage. They are common species of woodlands and forests and/or woodland and forest edges, and are available from native plant nurseries (see resources page). The research that is available also shows that they generally have high survival when introduced as seed. They generally self-sow and/or spread vegetatively so will spread once established.

These species could be used with the highest probability of immediate success in the initial phase of a woodland restoration project and would be the easiest for commercial growers to supply. They are also good choices when there is a need to revegetate quickly, and to regain some functions of the herbaceous (understory) layer. A good example is after honeysuckle removal, which often leaves behind areas of bare soil that need revegetating.

High restoration potential species are also good to introduce when the goal is to revegetate relatively quickly, because they self-sow and/or spread vegetatively. The disadvantage is that these species produce few seeds that do not tolerate dry storage; therefore the best way to introduce them is through transplants.

Medium to low restoration potential species include those that are highly desirable for their beauty and function. For example Virginia bluebells (Mertensia virginica) and hispid buttercup (Ranunculus hispidus) produce beautiful showy flowers in the spring, and they also take up substantial nutrients in the spring, when the potential for leaching is high. These species are best introduced using transplants.

It is not logistically or economically feasible to introduce these species at a watershed or landscape scale; however they would be a good addition to smaller areas, for example restorations in urban areas.