Take care to avoid harmful plants in the yard
Many people have no idea how important it is to be familiar with plants they choose to place in gardens. Although many are beautiful and so tempting to have, some plants can have potentially devastating results for nearby woodlands, fields or streams. It’s critical to know the ramifications of trees, shrubs, and herbaceous plants prior to planting.
The importance of using native species is emphasized because native species (plants from the geographic area) do not get out of control and do not become invasive. Native plants also require much less maintenance.
Invasive species typically travel by seed or by root. If they travel by seed, it is often by birds. The birds eat the fruit and as they sit on fencerows or trees, they poop the seeds out and start new plants. Some seeds can also spread by catching on animal fur. The seed head typically has barbs, or hooks, and when the animal walks by the seed head sticks to the fur until it gets brushed off, or scratched off at another site.
Or the plant can simply self-sow, producing so many seeds they just simply have to fall below the seed head and grow huge patches. This is how Teasel (Dipsacum laciniata), a very invasive biennial, spreads. Teasel is most often seen along the highway, especially near entrance and exit ramps, and bridges where it is hard to mow.
Homeowners are not the only culprits in spreading invasive species. The Conservation and Transportation Departments have been guilty of this in the past. The Missouri Department of Conservation planted multiflora rose and autumn olive decades ago, thinking they would provide good wildlife food and habitat. It wasn’t until years later that they discovered both were fast becoming invasive all over the state. The Missouri Department of Transportation planted crown vetch along steep highways, entrance and exit ramps, and other places for erosion control. Again, this plant quickly showed its invasive nature and is banned from all use.
These examples show the importance of continued study of the effects of plants introduced into natural landscapes around us. It is naïve to think our actions have no impact on the surrounding environment. Our gardens and landscapes can be beautiful reflections of us, our tastes and our sanctuaries for relaxation, but they also come with responsibility.
Lynn Youngblood is the executive director of the Blue River Watershed Association in Kansas City. Reach her at TheGreenSpace@sbcglobal.net.
PLANTS TO AVOID
Alan Branhagan, former horticulturalist at Powell Gardens, developed this list of invasive species:
Plants that are severe pests and whose seeds are dispersed far and wide by birds
or other animals. These should not be planted and all existing plants should be removed.
• Oriental Bittersweet Celastrus orbiculatus: (woody vine) known as the kudzu of the north. Alternate: American bittersweet Celastrus scandens.
• Winterberry Euonymus Euonymus fortunei.
• Japanese Honeysuckle Lonicera japonica and cultivars “Hall’s,” “Purpurea” and "Reticulata.”
• Amur Honeysuckle Lonicera maackii: (Bush honeysuckle).
• White Mulberry Morus alba.
• Bradford pear and Callery pear Pyrus calleriana including all cultivars "Bradford,” “Aristocrat,” “Autumn Blaze,” “Chanticleer” and others.
• Multiflora Rose Rosa multiflora (large shrub).
• Sericea Lespedeza sericea – on the noxious weed list.
• Purple Loosestrife Lythrum salicaria.
• Nodding Thistle. There are numerous native thistles that are not invasive.
• Bull Thistle Cirsium vulgare.
• Greek Foxglove Digitalis ferruginea (This is not the English Foxglove.).
• Teasels Dipsacum laciniata and similar species.
• Tall Fescue Festuca arundinacea.
Plants that are severe pests near where planted but whose seeds do not disperse great distances. These plants should not be planted near natural lands.
• Amur Maple Acer ginnala: (small tree).
• Tree-of-Heaven Ailanthus altissima.
• Sweet Autumn Clematis Clematis terniflora/ C. paniculata.
• Burning Bush Euonymus alata.
• Golden Rain Tree Koelreuteria paniculata.
• Boston Ivy Parthenocissus tricuspidata.
• Crown Vetch Coronilla varia.
• Yellow Flag Iris Iris pseudacorus.
• Perennial Sweet Pea Lathyrus perennis.
• Bird’s foot Trefoil Lotus corniculatus.
Plants that are severe pests in certain parts of the Midwest and should be monitored for invasiveness. Use is discouraged near nature preserves.
• Norway Maple Acer platanoides
• Japanese Barberry Berberis thunbergii and cultivars: (shrub)
• Privets Ligustrum spp. In the South the Chinese privet Ligustrum sinense is a horrific pest to woodlands and this plant is supposedly hardy only to zone 7 but there are several big shrubs of its variegated cultivar growing in the Kansas City area.
• Viburnums Viburnum spp.
• Hardy mimosa Albizzia julibrissin var. Rosea.
• Butterfly bush Buddleia davidii.
• Purple Beautyberry Callicarpa dichotoma.
• Rose-of-Sharon Hibiscus syriacus.
• Pyracantha Pyracantha species and hybrids.
• “Pampas” grass Miscanthus sacchariflorus