Invasive plant removal can create disturbances that leave areas susceptible to new invasive infestations. To make all of the hard work removing invasive plants worth it, native ecosystems need a head start in order to reclaim space from aggressive invasive offenders. Planting native ground cover, herbaceous species, and shrubs can help rebuild the landscape. Otherwise, the pre-existing infestation may return, or a new opportunistic invasive can take root. Removal sites should be treated like restoration projects that need to be monitored and nurtured as native vegetation moves back in. This may seem intimidating, but we are here to get you started down the right path.
Disturbances happen naturally in the wild, leading ecosystems to respond by beginning the regeneration process. Native pioneer species like goldenrods, asters, and grasses will be some of the first to emerge and begin rebuilding the understory. You can see these plants at work along roadsides or other anthropogenic areas that specialist species tend to avoid. It’s important to plant these early successional plantings shortly after a removal to take the first step towards native restoration. Ideally, these sites should be replanted within one week after removal.
Some restoration plantings are site-specific, but the most successful ones are generalist species that can adapt to a variety of conditions. Wrinkleleaf goldenrod (Solidago rugosa) is a great example of an early successional generalist native plant that can be found anywhere from shaded woodlands and wetland margins to dry open fields. One of the first to colonize disturbed spaces, wrinkleleaf goldenrod makes an excellent competitor in areas that were previously infested with invasive herbaceous plants like garlic mustard (Alliaria petiolata).
Selecting the best plants for the job is not always as simple as throwing some wrinkleleaf goldenrod on barren soil. The right plant may vary based on the light availability, soil moisture, and surrounding vegetative communities at your removal site. To break things down, we’ll outline how to implement successional plantings distinguished by growing conditions.
Open areas
Starting small
Developing a hardy ground cover is one of the most important steps to give native species a fighting chance. Low-lying invasive Japanese stiltgrass (Microstegium vimineum) meets its match with native nimblewill (Muhlenbergia schreberi). This grass species fills space and dissuades invasive grow-back with its dense coverage. It is one of the only native species that can put up a good fight against Japanese stiltgrass before an invasive removal. Similarly, wild strawberry (Fragaria virginiana) can help hold space from early emerging invaders, giving other native species a chance to take root and you a chance to pull any young invasive sprouts. Both of these plants thrive in dry nutrient-poor soils and can handle considerable foot traffic.
Other ground covers should be mixed in to support native biodiversity, and many are likely to pop up on their own if they have been established in the area previously. If existing source populations are nearby, species like cinquefoil (Potentilla simplex), trailing arbutus (Epigaea repens), and reindeer lichens (Cladonia spp.) will creep into dry areas, carpeting the ground with green mosaics.
Adding dimension
After planting ground cover, mimic natural succession by introducing grasses and forbs. Wildflowers like goldenrods and asters will thrive in dry sandy soils alongside native bunchgrasses that fill space with dense clumps. Switchgrass (Panicum virgatum), Indian grass (Sorghastrum nutans), and little bluestem (Schizachyrium scoparium) are important components of native meadows that work well in restoration projects. Other grasses like path rush (Juncus tenuis), forked witchgrass (Dichanthelium dichotomum), and Heller’s rosette grass (Dichanthelium oligosanthes) can fill more space closer to the ground, allowing other species to weave throughout.
Goldenrods like wrinkleleaf goldenrod (Solidago rugosa), silverrod (Solidago bicolor), and old field goldenrod (Solidago nemoralis) add more coverage and late-season resources with their dramatic fall blooms. Mix in asters like showy aster (Eurybia spectabilis) and New York aster (Symphyotrichum novi-belgii) along with pearly everlasting (Anaphalis margaritacea) and plantain-leaved pussytoes (Antennaria plantaginifolia) to develop a robust diversity of species.
Planting powerhouse shrubs
Shrubs are likely to follow suit if the ground cover and herbaceous plantings succeed, but introducing them will help speed up natural succession which can take years. Open areas often fill in with sweet fern (Comptonia peregrina), yellow wild indigo (Baptista tinctoria), sheep laurel (Kalmia angustifolia), and black huckleberry (Gaylussacia baccata) if source populations exist nearby.
Forested areas
Starting small
Productive forest regeneration relies on balance and biodiversity within the understory. If the lowest layer of vegetation smothers other plants, seedings are not able to take root and replace old trees as they die. As in more open areas, a mix of wild strawberry (Fragaria virginiana) and wintergreen (Gaultheria procumbens) will likely thrive under canopy cover and leave room for saplings to establish. Other species, such as Canada mayflower (Maianthemum canadense), starflower (Lysimachia borealis), and wild geranium (Geranium maculatum) specifically favor the shady moist conditions that forests provide.
Encourage the growth of mosses and low growing grasses like poverty oatgrass (Danthonia spicata), Pennsylvania sedge (Carex pensylvanica), and wavy hair grass (Deschampsia flexuosa) to add additional ground cover. This diverse base will set the stage for the iconic woodland plants like ferns and intricate wildflowers.
Adding dimension
Ferns do a great job fending off invasive species because they form groves which fill space and create shade. Easy to establish and fast growing, ferns are a foolproof backup plan if other plantings aren’t taking to an area. Cinnamon fern (Osmundastrum cinnamomeum), New York fern (Parathelypteris noveboracensis), sensitive fern (Onoclea sensibilis), and Christmas fern (Polystichum acrostichoides) are all good choices.
Grasses and forbs are as important in forested restoration areas as they are in open ones. Wrinkleleaf goldenrod (Solidago rugosa), sweet goldenrod (Solidago odora), downy goldenrod (Solidago puberula), and grass-leaved goldenrod (Euthamia graminifolia) will grow happily in woodlands under low sunlight. Goldenrods are notoriously fast-growing native plants that can help naturalize sites that are recovering from an infestation. Shade tolerant asters like wavyleaf aster (Symphyotrichum undulatum) and toothed white top aster (Sericocapus asteroides) will grow alongside goldenrods, forming cover called “soft landings” under trees for beneficial insects. Some of the more flashy wildflowers like red columbine (Aquilegia canadensis) also provide expansive cover while adding to the biodiversity of the understory.
Planting powerhouse shrubs
If you walk through the oak and pitch pine woodlands on Martha’s Vineyard, you’re likely to see lowbush blueberries and huckleberries decorating the forest floor. There’s no reason for your restoration site to look any different! While these shrubs may eventually emerge on their own, if you want to get ahead of things consider planting a mix of lowbush blueberry (Vaccinium angustifolium) and black huckleberry (Gaylussacia baccata).
Restoration plantings alone are not enough to defeat invasive infestations, and neither is simply ripping out invasive species. These plantings are meant to help rebuild ecosystems that have been disrupted by invasive disturbance. The affected areas will need to be stewarded with care and patience, requiring attention to detail and continuous removal of invasive regrowth. But the results with be worth it; if you are going to pour time and energy into removing invasive species you might as well do it right!
