Walking around Beverly Shores as I often do, I can’t help but gaze into the many small wooded lots that exist in our community. I am deeply saddened by how degraded many of them have become, containing almost exclusively exotic weeds like bush honeysuckle, oriental bittersweet and burning bush. My chief motivation for writing this series of articles is to encourage land owners not only to avoid planting the worst invasive plants but to recognize them in their own woodlands and, if so inspired, to remove them. This could help preserve and enrich the Beverly Shores community of wild plants and animals.
Many of our most invasive and difficult-to-eradicate plants feature attractive leaves, flowers, and/or fruit. They also possess great hardiness, wide tolerances of light, moisture and poor soils and are unpalatable to deer. All of these features make them very troublesome in natural areas where they spread and displace our native flora. With the loss of diversity of native flora comes a decrease in diversity in native fauna: all of the moths, butterflies, beetles, and other insects and invertebrates, not to mention micro-organisms, that have evolved for thousands of years with these native plants. Their struggles in turn affect larger animals and, indeed, every life form in our complex web of life.
Lily of the valley (Convallaria majalis) is a good example of an attractive, hardy, and difficult-to- eradicate non-native plant (with a sweet fragrance used in the perfume industry). Once its rhizomes colonize a woodland, eradication can take years and much labor and/or herbicides. Lily of the valley is a native of Europe and has been used as an ornamental in the United State for many years. It is also a very poisonous plant (another good reason to avoid it). All of its parts, including its attractive, red berry-like fruit, contain compounds called cardiac glycosides. Cardiac glycosides affect heart muscles and so are sometimes used medicinally, similar to digoxin derived from foxglove (Digitalis spp.). Lily of the valley spreads readily by rhizomes, or underground stems, and seemingly persists forever, wherever it has been planted.
Bishop’s Weed (Aegopodium podagraria) is a highly invasive and enduring ground cover that is not yet a big problem in Beverly Shores, to my knowledge. Google it and you will discover that it is sold by well-known nurseries, but read gardener comments and you will find considerable hatred lavished on the plant by those who have had it take over their landscaping. This plant has a long list of alternative common names including goutweed, ground elder, creeping Charlie, and snow in the mountain, but perhaps is best illustrated by a photograph. According to the Plant Conservation Alliance’s Alien Plant Working Group, this plant is currently considered invasive in natural areas in 6 states, including Michigan and Wisconsin, and has naturalized in 29. It forms dense patches and reduces native diversity. I consider it just waiting in the wings to become a major pest in our community.
Both lily of the valley and bishop’s weed can be removed by pulling and digging. Be sure to dispose of the plants in garbage bags or they can re-sprout. Both are also susceptible to glyphosate-containing herbicides like Roundup. Lily of the valley is most susceptible when its tender leaves are just emerging in the spring. When using any pesticide like Roundup, be sure to carefully follow all label directions, as required by state and federal laws.
Moneywort, also called creeping jenny (Lysimachia nummularia), is unfortunately another popular ground cover. Because of its long, creeping stems, it is also popular for dangling from potted plant arrangements. Moneywort is sold with its natural, green leaves but also with yellowish leaves like the varieties gold creeping jenny or “gold moneywort aurea.” Moneywort is of particular concern to ecologists in moist woods and wetlands where it thrives, choking out the native plants. It forms new roots at the leaf axils and then branches out at these new roots, continuing this process of sprouting roots and branching until a dense mat is formed. Moneywort has escaped in most of the lower 48 states. You can successfully eliminate moneywort by hand pulling. Again, bagging of plants is a useful idea to prevent re-sprouting. If you want to use an herbicide, be very careful if the moneywort is growing near water. Roundup cannot be used near bodies of water.
Elsewhere in this series, I have mentioned partridgeberry, bearberry and wild ginger as good native substitutes for invasive ground covers. Partridgeberry and bearberry are evergreen while wild ginger dies back each winter. If you want dense groundcover that grows quickly, try Virginia creeper (Parthenocissus quinquefolia). The plant, used by the city of Chicago in the planters in the center of Lake Shore Drive, grows commonly as a native in Beverly Shores’ woodlands. Virginia creeper will need pruning if it spreads excessively, particularly since it can climb on trees and structures. It provides beautiful red color in autumn.
Vigilant homeowners in Beverly Shores can prevent the destruction of their woodland by removing oriental bittersweet. Because the understories contain a wide variety of vines, mostly native species, and some can look similar to bittersweet, the Environmenal Restoration Group (ERG) will be glad to help identify plants for you and make suggestions for removal and for native replacements. Don’t hesitate to contact Terry Bonace (email@example.com), Candice Smith (firstname.lastname@example.org), or Bill Schaudt (email@example.com) for assistance. Also, please visit our website at www.bserg.org for further information on invasive plants and native replacements.