Non-native plants can overtake home landscapes

Invasive plant species purchased at garden centers may enhance a landscape’s aesthetic appeal, but they also can turn idyllic outdoor spaces into battlegrounds for ecological balance.

Damages caused by invasive plant species—introduced by human activity into regions where they did not originate—cost Virginians more than $1 billion annually. Nationally, that figure exceeds $120 billion, according to the Virginia Invasive Species Working Group.

Henrico County floral arranger Mary Vetrovec has a cautionary tale regarding invasive species. As a new gardener 30 years ago, she planted an ornamental-yet-invasive groundcover called houttuynia.

The chameleon plant, also known as a rainbow plant, has a high vegetative growth rate. Uncontained, it quickly overtakes gardens and is difficult to control.

“I was a new gardener, and I had a lot of shade, so anything that would live in shade, I would plant,” said Vetrovec. “But this will take over the ground, eat your children, pets and house!” she joked.

Vetrovec advises home gardeners to research new varieties. The website plantvirginianatives.org lists common invasive species, and native alternatives for Virginia gardens.

“Look at the do-not-plant website, and listen!” she urged.

Ed Olsen, a Virginia Cooperative Extension horticulture specialist in Henrico County, said other popular ground covers like English ivy can crowd out native flora from the ground or forest floor.

“It makes a monoculture, while we want to encourage diversity,” Olsen explained. “Also, ivy is prolific at self-seeding, so it can move to someone else’s property or area.”

Vetrovec said she managed to contain the climbing ivy in her yard by cutting it at the base around the tree, and mowing low to the ground.

Instead of ivy, Olsen recommended Allegheny pachysandra, a semi-evergreen ground cover native to the Southeast.

“Ferns are a great ground cover too,” he added. “A pretty plant for your garden where there’s moisture.”

Japanese wisteria is another non-native that tends to overwhelm gardens.

“When Japanese wisteria is flowering, it is beautiful, but it’s also suffocating and aggressive, and can damage trees,” Olsen said. “But there is a native American wisteria that can help with the coloration you want, and is great for local pollinators, and deer-resistant.”

Chinese sumac, or tree of heaven, is anything but, horticulturalist Mark Viette said on a 2014 episode of Virginia Farm Bureau’s weekly TV program Real Virginia.

“We’re finding out it’s not a tree from heaven; it’s a tree from somewhere else,” he quipped. “This tree produces seed pods that spread all over. Cutting it down makes it worse. The roots go out 20 to 30 feet or more and produce a hormone that prevents other plants from growing well.”

Viette said chemical treatment is the most effective way to eliminate this tree.