3 minute read
Time To Take Action Against Invasive Plants
Andrea Zani
Andrea Zani is managing editor of Wisconsin Natural Resources magazine.
Look around your yard — what’s that weed? It could be a harmless flower you’d want to keep, or it might be an invasive species.
Here’s a quick primer on four common invasives, how to recognize them on the landscape and how to handle them when you do. For details on these and the 100-plus other terrestrial plants listed as invasive under Wisc. Admin. Code NR 40, check dnr.wi.gov/tiny/2711.
WILD PARSNIP (PASTINACA SATIVA)
Harm done: Can cause blisters and rashes if sap contacts skin in sunlight. (Giant hogweed, Heracleum mantegazzianum, is another carrot family plant that causes blistering.)
Look for: Plants growing in sunny areas up to 5 feet tall, with grooved stems, toothed leaves and small yellow flowers.
Control: Pull completely or cut from the taproot. Mowing can work if done before seeds enlarge to avoid spreading. Foliar herbicides are effective.
CROWN VETCH (SECURIGERA VARIA)
Harm done: Quickly takes over landscapes, even covering shrubs and small trees.
Look for: Dense carpet-forming plants with purple-pink and white flowers.
Control: Hand-pull, including roots, for minor infestations. Repeatedly mow larger patches or cover with black landscape plastic or fabric for one growing season. Foliar sprays offer chemical control.
GARLIC MUSTARD (ALLIARIA PETIOLATA)
Harm done: Can take over landscapes, usually in shady areas, suppressing native plants.
Look for: Dark green basal leaves on first-year plants, and triangular stem leaves with large teeth on second-year plants. Small white flowers bloom in spring.
Control: Pull plants, including taproots, and place in a plastic bag for trash disposal. Chemical control works for dense infestations.
TATARIAN HONEYSUCKLE (LONICERA TATARICA)
Harm done: Alters habitats by reducing light and depleting soil. May release chemicals inhibiting other plants.
Look for: Dense, deciduous shrubs with multiple stems growing 6-12 feet (several species of honeysuckle exist in Wisconsin).
Control: Dig or pull smaller plants. Prescribed burns are used on large areas, and chemical treatments are available.
To Do List
Invasive plants can grow anywhere and quickly overwhelm native species, negatively affecting the environment, economy and human health. But there are many ways to help rid the landscape of these harmful invaders.
Learn about invasives: June is Invasive Species Action Month, and getting educated on invasives is an excellent first step. The DNR has you covered; dnr.wi.gov/topic/invasives. Also check out the First Detector Network from UW-Madison Extension, fyi.extension.wisc.edu/wifdn, and the Renz Weed Science Lab, an especially good resource for land managers, renzweedscience.cals.wisc.edu.
Join IPAW: The nonprofit Invasive Plants Association of Wisconsin promotes natural resources stewardship by helping people understand invasives and how to stop their spread; ipaw.org.
Support a CISMA: Cooperative Invasive Species Management Areas work regionally in Wisconsin, coordinating resources, expertise and local action against invasives; dnr.wi.gov/tiny/2706.
Volunteer at an SNA: Wisconsin’s beautiful state natural areas need your help to keep them healthy with tasks such as controlling invasive species and collecting seeds of native plants to spread their growth; dnr.wi.gov/tiny/2556.
