Whether your garden sprawls across acres of landscaping or across a balcony of pots, April is finally the month most of us can start stirring up the soil for a new year of fabulous flora. Can you dig it?
Now’s the time to not only yank the weeds out of your plant beds, but the vigorous vegetation that’s just as problematic: invasive plants. They’re not the same as weeds, but can be just as detrimental.
The U.S. Department of Agriculture even rounds them up in a list.
City or suburbs, where we live and work isn’t the ecologically productive land it once was. Humans have crowded out fully functioning ecosystems that used to support wildlife, and a lot of the green spaces we’ve designed into them is full of stuff that simply doesn’t belong here.
“Invasive plants are plant species which originally came from a different part of the world than where they are currently growing,” explained Jessica Shahan, naturalist at Newlin Grist Mill in Glen Mills. “They were introduced usually through human actions, either on purpose through plantings or accidentally when seeds or other plant parts were unintentionally moved between locations.”
Your local nursery is packed with alien species from other countries, and cities and towns have been planting them willy-nilly for years.
According to the National Audubon Society, “native oak trees support over 500 species of caterpillars whereas ginkgos, a commonly planted landscape tree from Asia, host only five species of caterpillars. When it takes over 6,000 caterpillars to raise one brood of chickadees, that is a significant difference.”
It’s all about being bug- and bird-friendly. However they got here, and whatever their size, invasive plants often find themselves with no natural checks, such as diseases, pests or inhospitable weather, and no attraction for local pollinators at the center of the garden food web.
“They cause problems in our local ecosystems by growing quickly, covering large amounts of area, and using up many of the resources available to the plants that are supposed to be there,” Shahan continued. “This results in less space and resources for the native plants that our wildlife rely on for food and shelter.”
Left to their own weed-like ways, invasive plants can crowd out native species and lead to the endangerment or even extinction of local plants.
In a park the size of the Newlin Grist Mill, large-scale invasive removal isn’t possible, so Shahan’s team focuses their efforts on specific locations of high importance, such as those with high biodiversity, areas that provide important breeding habitat for wildlife, sites home to rare or significant plant species, or ones used in the park’s environmental education programs.
Every year, gate-crashing vines are cut and pulled, trees and shrubs are axed, and herbaceous species are dug out and replaced with greenery that’s supposed to grow in southeastern Pennsylvania.
“We choose species that provide significant food and shelter resources for birds, native pollinators, and other wildlife that live in the park,” Shahan said. “Favorite trees include oaks, maples and hickories, plus lots of milkweed, asters and other nectar plants for monarch butterflies.”
To learn more from Shahan or join the battle against invasive plants at Newlin Grist Mill, you can volunteer for their Earth Day clean-up on April 20.
For another opportunity to go green, Green Philly hosts the inaugural Green Week April 18 to 25 to celebrate organizations that are hosting events to promote sustainability.