Fall is good time for neighborhood invasive species removal: botanist
HOUGHTON — The problem with invasive species — they are easy to spread but incredibly difficult to get rid of.
“If you are doing a great job on your property but your neighbor’s not, that’s going to become your problem,” said Jill Fisher, botanist and educator with the Keweenaw Invasive Species Management Area (KISMA). Fisher works to make residents aware of problem plants and how to remove them.
On Tuesday she spoke at the Portage Lake District Library, where audience members had plant samples in tow. Fisher used the time to focus on Japanese barberry, glossy and common buckthorn and knotweed.
Fall is the ideal time to remove these varieties, as they remain green long after the native plants, she explained.
“Invasive means, it really just takes off,” Fisher said. “They didn’t come from here, they didn’t co-evolve with the other species and the other organisms in our area … So, without these controlling factors they can really reproduce rapidly and grow rapidly and then they can take over, which causes a disturbance,” Fisher said.
Fisher first addressed common buckthorn. Introduced as an ornamental plant, as many invasive species are, common buckthorn has dark purple berries that cluster near the parallel, spatula-shaped leaves, orange inner bark and a long growing season.
The buckthorn damages native plants by altering the nitrogen and carbon levels in the soil, promoting oat rust disease and taking over regions they inhabit.
To remove, smaller growths can be pulled by hand, and larger plants should be cut to stumps and covered with a Buckthorn Baggie or capped with herbicide. Otherwise, the buckthorn will sprout more shoots in spring and simply regrow.
Next came the glossy buckthorn, identifiable by red berries that darken to purple, red roots, and glossy, spatula-shaped leaves. This variety can impact native birds, Fisher explained, upsetting their digestive systems when unripe and spreading far and wide when ripe.
Like the common buckthorn, this glossy counterpart edges out native plants and also takes over wet soils draining damp areas of moisture. The glossy buckthorn can be removed using the same methods as its relative.
Third was the Japanese barberry, a decorative bush that is still sold in greenhouses and commonly used in landscaping.
“A lot of our problem plants are pretty,” Fisher said.
A spiny shrub with pale yellow flowers, red berries, grooved branches and small spatula-shaped leaves that are either green or red, the barberry increases pH and nitrogen levels in the soil. More notably, areas with barberry invasions harbor large numbers of ticks, creating another health risk.
Like with the Japanese barberry, small Japanese barberry plants can be pulled out. For larger plants, applying herbicide to the stumps or directed burning are the best methods for removal.
Fisher also mentioned Japanese knotweed, although it is too late in the year to remove them now. In spring, watch for bamboo-like stalks, spade leaves and clumps of small white flowers in summer.
“The key to all of these invasives is to be knowledgeable about them,” Fisher said. “It’s ideal to catch invasive species early on, but more established varieties must be continuously pushed back to prevent takeover. When removing invasive species be careful to prevent reinfection.
“We have to have a good attitude, we have to not give up,” Fisher said.
She said the more hands removing invasive species and watching for signs of infection, the better.