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MD Invasive Plants Law

By Jean Siers

September 13, 2024

In my life, I have owned two houses. The first, in Charlotte, NC, had a sweet little front porch with a sheltering tulip poplar offering shade all summer. Next to the poplar was a plant I had never seen before.

That first spring, the vining plant bloomed with draping, fragrant purple flowers. It was lovely. And then it grew. And grew. It climbed the tulip poplar. It grew into our gutters. We finally identified it as Chinese wisteria. After a couple years we cut it to the ground. Then cut it back again. And again. We tried digging it out. When we moved to Maryland 30 years later, an occasional shoot would still appear from the ground like something from a Stephen King novel.

Our new home in Salisbury had pretty minimal landscaping, but the front hill had enormous patches of unkempt English ivy. One patch was particularly tall and unruly, and in May, a tiny bloom appeared out of its midst. The ivy had grown over a full-sized azalea. We have spent the past two years digging it out and cutting it off the trees before it causes permanent damage. By our front door, tiny nandina and Chinese holly sprout regularly through the native plants I’ve put in their place.

Our brushes with invasive species are not unique. Since 2011, Maryland has banned the sale of six invasive plants, which they labeled as Tier 1. These include yellow iris (aka yellow flag or water flag), wintercreeper, and shining geranium. The state required posted warnings on 13 more, which are considered Tier 2 (plant with caution), and includes barberry, scotch broom, nandina, Callery pears, and both Chinese and Japanese wisteria.

After extensive efforts from environmental groups across the state, in June, Gov. Wes Moore signed the Biodiversity and Agricultural Protection Act, which will take effect Oct. 1. By that deadline, the Maryland Department of Agriculture will create a list of plants that must no longer be sold. New plants can be added to the list as time goes on. A preliminary list is available here and the updated list will replace it when finalized.

Under the new law, garden centers and nurseries will have a year to sell the plants designated by the Ag Department as invasive (two years for woody plants). Once the stock of listed plants is sold out, they cannot be restocked.

This isn’t just a matter of what is pretty or not.

For instance, the invasive but commonly planted Japanese barberry can invade pastures and damage grazing land. It changes the pH of the soil and also changes the microclimates around it, creating a moister environment that is prime habitat for deer ticks that can carry Lyme disease.

Yellow iris, a beautiful flower seen in Maryland’s ditches and waterways, is also highly invasive and can be damaging in agricultural settings. Its thick rhizomes choke out native plants and hold sediment which can then clog ditches and encourage flooding in fields and roadways.

I’m excited to see Maryland moving forward with better regulation of invasive plant species. Removing them from local garden centers is a great first step. But each of us needs to begin educating ourselves on how to identify invasive plants and how to remove them from our gardens; our ditches, streams and rivers; our farms; and our forests. Biodiversity depends on it.

Jean Siers is the Regional Director of Society of St. Andrew’s Delmarva office, a WET board member, and a Maryland Extension Master Gardener Intern.