Clearing Out Invasive Plants
Some intruders are troubling the waters of the Bronx River and the lands around it, and restoration workers are devoted to cleaning them out. The intruders are invasive plants that are not native to this area. The workers travel the river on foot and by canoe, digging the plants out root and branch wherever they find them.
In a workshop held on Oct.16, Jennifer Plewka, the environmental educator for Phipps Community Development Corporation, explained how the invasive plants got here and showed students how they could help the workers clear some of them out of Drew Gardens. Ten-year-old Scott Mitchell helped her out by showing students how to use special tool she called a “root grabber” and he called a “picker.”
The first step was learning to identify the offending plants:
Japanese knotweed, a nice-looking plant that originally was brought to Europe from Asia to ornament gardens. Then it traveled here where it has become a pest. It establishes its dominance when dead leaves and stems around it spread a chemical in the soil that prevents other plants from growing.
Bindweed also came from Europe and Asia, probably arriving along with farm and garden seeds. It might also have been brought in as an ornament because of its pretty purplish white flowers and climbing vine. First noticed growing wild in California, it quickly became notorious as the worst weed in the western states.
The white mulberry tree was brought to this country from Asia in colonial times as a food source for silkworms. It became a threat when it started mixing with the native red mulberry tree, transmitting a root disease.
Purple loosestrife was growing densely along the river bank at Drew Gardens. This “beautiful killer,” which has lovely purple flowers in the summer, likes wet places and once it gets started crowds out all the local vegetation that wildlife depend on. It’s especially hard to get rid of because it can regenerate from any tiny piece of root left in the soil.
All the offending plants usually get started in polluted areas or places that have been disturbed by urban development, road-building and such. They can travel by air, in the water, or in soil that is moved from place to place.
After the students, who came from Bronx River Art Center after school programs, collected some specimens of the plants, Jennifer showed them how to preserve the specimens by layering them in sheets of newspaper and corrugated cardboard.