Invasive plants – non-natives that spread uncontrollably – are very tough competitors. Some are prolific producers of seed, trusting their wide dispersal to birds, other animals, or the wind. Some produce aggressive root systems or tubers that spread like a vegetative army, overcoming all native plants in their path. Many employ a mix of strategies.

This article will focus on several species that are all too common in our community: lesser celandine, English ivy, autumn and Russian olive, nandina, Japanese and bush honeysuckle, and Japanese stiltgrass. Unfortunately, that’s only a small portion of the invasives that threaten our native plant (and thereby, our native insect) heritage.

Many invasives have an additional characteristic that aids their spread: They are attractive. For evidence, just take a springtime stroll along Paul Spring (roughly where it crosses Rippon) and head west. You will find its banks and surrounding areas carpeted by a lovely, low-lying plant with dark green leaves and brilliant, shiny yellow flowers.

Lesser Celandine, aka Fig Buttercup (Ficaria verna)

As lovely as it is, you are witnessing an invasion of sorts – by lesser celandine, a non-native plant that most likely got its foothold in our area after being planted as an ornamental, as did many of the plants in this article. But its beauty masks its destructive nature. It crowds out our native flowers, depriving native insects and bees of the host plants and pollens they need to survive and reproduce.

If a small patch occurs in your garden, it’s possible to dig it up (make sure you get all the root material, bulblets, and tubers), bag it, and put it in the garbage—never a compost bin. But beware: It can spread aggressively. Don’t let it get a foothold in your yard!

Lesser celandine likes moist soils and can be replaced by marsh marigold, wild ginger, bloodroot, twinleaf, and celandine poppy.

English Ivy (Hedera helix)

English ivy, an attractive, hardy plant that adds a touch of green to the gray winter landscape, has been planted in our gardens for decades now. But if there was ever a case of too much of a good thing, this is it.

English ivy now covers acres of our parkland and our backyards, choking out native flowers such as mayapple, cut-leaved toothwort, and spring beauty, depriving native insects of the pollen and nectar they require for survival. It also harbors mosquitoes; they like the moist, shady environment it creates. So by removing English ivy, you will also be helping to eliminate those pesky mosquitoes.

English ivy’s horizontal spread is destructive enough, but it also grows vertically. If it’s allowed to climb up trees, it can overtake the canopy, hog all the sunlight, and kill host trees. English ivy only flowers and makes seeds when high off the ground; if it is allowed to reproduce above, birds will carry its seeds far and wide.

If you have English ivy in your backyard, it’s recommended that you tackle the vines growing up your trees first, by carefully cutting them off the tree (try not to damage the bark) and pulling its roots away from the base of the tree. On the ground, English ivy can be dug up by hand, one patch at a time—again, try to get up all the roots you can.

If you are removing English ivy from a steep slope, Plant Nova Natives recommends putting down a jute fiber net to prevent erosion. You can also cover such areas with woodchips (as much as eight inches deep), clear a spot in the woodchips, and plant a native directly into the ground. The breakdown of chips over time will create new soil and suppress the ivy from re-emerging.

The Virginia Native Plant Society recommends replacing English ivy with evergreen or semi-evergreen plants such as creeping phlox, wild ginger, foamflower, and mouse-eared coreopsis. Other possible replacements include a combination of golden groundsel and wild blue phlox, Christmas and wood ferns, fringed and seersucker sedges, green-and-gold, American coralbell (alumroot), hairy alumroot, Virginia knotweed, zigzag goldenrod, and heart-leaved aster.

Autumn Olive (Elaeagnus umbellata)

Autumn olive is a vigorous plant that can grow as high as 30 feet with an additional allure: Its scent in late fall is heavenly. But it is also extremely invasive. You can recognize autumn olive (and its close relative, Russian olive) by the silvery-white undersides of its leaves and by the dense thickets it produces when allowed to grow unmolested. It has been widely planted in hedgerows, as a green fence between properties. It is a prolific seed producer. A walk through our parks will reveal many autumn olives growing courtesy of seed-dispersing birds.

You cannot just cut autumn olive down to its roots. That will only encourage denser growth. In order to eradicate it, you must cut it down and dig out the stumps and roots. If all else fails, some recommend painting its stumps with glyphosate herbicide (Roundup). Just be aware that glyphosate herbicides kill every green plant they come in touch with, can last for up to six months in the soil, and are highly toxic to fish and other wildlife. If you choose to use a glyphosate herbicide on any of the plants mentioned in this article, it’s critically important to follow all directions to the letter.

Native substitutes include Virginia sweetspire, elderberry, winterberry, downy serviceberry, and several native viburnums.

Nandina, aka Heavenly Bamboo (Nandina domestica)

Another ornamental that was widely planted in our community to provide greenery throughout the year—with the added benefit of a splash of red berries all winter long—is nandina. Although it looks nice, it’s virtually useless in an ecological sense—none of our native insect species use it as a host plant, and its bright red berries, though attractive to some birds, contain small amounts of cyanide. These berries are toxic to dogs and cats; if set upon by a flock of hungry cedar waxwings, they can sicken or even kill these beautiful birds.

The best way to rid your yard of nandina is to dig it out. Remove as much of the root system as possible. Then stay vigilant and dig out any sprouts that attempt to reestablish themselves. If you absolutely can’t part with nandina, consider clipping off, bagging, and throwing out its red berries, for the sake of birds and other wildlife.

Nandina can be replaced by small native trees including redbud, serviceberry, fringe tree, and flowering dogwood. Additional substitutes include evergreen American holly and inkberry, Virginia spire, deciduous American beautyberry, summersweet, winterberry, spicebush, and fragrant sumac.

Japanese Honeysuckle (Lonicera japonica) and Bush/Amur Honeysuckle (Lonicera maackii)

These related species are known for their fragrant, attractive flowers—and their ability to spread and form dense thickets. Both are now considered to be invasive alien plant species. The berries of bush honeysuckle are red; it spreads both by seed and vegetatively, forming dense stands of shrubs. The berries of the Japanese honeysuckle are black; it spreads by seed, underground rhizomes, and above ground runners. Its woody vines can form dense, tangled thickets.

Both species are best removed in early spring or late fall. Small plants can be pulled up by hand, including their root systems; larger bushes can be dug up and removed. If berries are present after pulling, do not compost them.

Coral honeysuckle is a native vine that can replace its invasive cousins. It has lovely red flowers that attract hummingbirds, and a long blooming season. Another benefit: It doesn’t spread into areas it doesn’t belong. Any of the native shrubs and trees listed as substitutes for nandina may also make good replacements for invasive honeysuckles, depending on your growing conditions.

Japanese Stiltgrass (Microstegium vimineum)

This annual grass forms dense communities primarily in moist soil in low light. Like English ivy and other invasives that spread on the ground, stiltgrass can dominate large swaths of land and choke out our native flowers. According to Virginia’s Department of Conservation and Recreation, a single plant can give rise to 100 to 1,000 seeds, which can remain viable in the soil for three to five years.

Japanese stiltgrass can be successfully removed from gardens and backyards by hand (it pulls up easily), preferably very late in the growing season before it produces seed. But there’s a catch: Because its seeds can survive for years in the soil, gardeners must repeat this process for a recommended seven years! Once eradicated, this invasive can be replaced by grasses such as switchgrass and little bluestem, or groundcovers such as green-and-gold, wild ginger, and golden ragwort (which, though native, also has a tendency to spread).

For more information:

For more information, see Plant NoVa Natives (plantnovanatives.org/invasive-plant-management), or Virginia Native Plant Society (vnps.org); for factsheets on specific plants, removal techniques, and alternate plantings, see the Virginia Department of Conservation and Recreation (dcr.virginia.gov/natural-heritage/factsheets#invasives). To purchase native plants, check out Earth Sangha (earthsangha.org) and Nature by Design (nature-by-design.com), among others. You can also learn more about invasive species at The North American Invasive Species Management Association (naisma.org), and the U.S. Department of Agriculture’s National Invasive Species Information Center (invasivespeciesinfo.gov).

One final word: If you are interested in removing invasive plants but feeling a bit overwhelmed, it might be best to start small. Target one manageable section of your yard, rid it of invasives, and plant just one native bush, tree, or a few smaller native plants this spring. Every small step is one in the right direction. If enough people take small actions, it will begin to slow the spread of invasive plants into our parks—and your neighbor’s yards.

– Andrew Keegan

Photos courtesy of Bugwood.org. Credits: Lesser celandine: Leslie J. Mehrhoff; English ivy: Chris Evans; Nandina: John Ruter; Autumn olive: Leslie J. Mehrhoff; Japanese honeysuckle: Charles T. Bryson; Japanese stiltgrass: Chris Evans.