Invasive Plants - Part II

by Dave Wilson

Dave Wilson brings us part two of a series on the negative impact of invasive non-native plants.

In the studio we are lucky to have Kerrie Kyde, the Invasive Plant Ecologist with the Maryland Department of Natural Resources. She is responsible for invasive plant assessment and control on some 475,000 acres of state lands. She is chair of the Maryland Invasive Plant Advisory Committee.

I want to start today by asking which species are of the most concern. Are there certain ones that the state sees as the most insidious?

Kerrie Kyde:
" "That is actually a difficult question. We tend not to approach invasive plant species management on a species basis. We approach it on an area basis or habitat basis. And there's a complement of species that invade particular habitat so I am very rarely looking for one individual species that I'm going to work on.

That being said, I will say that I would guess that wavyleaf basketgrass is the species that I'm most concerned about right now primarily because it is so new. Wavyleaf basket grass is a forest grass. It's perennial. It is stoloniferous, which means it has stolons which are stems that lie down along the ground and root at the tips or the nodes which means that it spreads vegetatively as well as making seed.

It also has an amazing long-distance dispersal mechanism. The awns which are bristles at the ends of the seeds get sticky, and in the fall anything that walks through patches of wavyleaf basketgrass can pull the seeds off the plant where they stick for as long as months and then drop off in brand new places. Wavyleaf basketgrass has only been documented in Maryland and Virginia which means that without being able to control it we are afraid it could spread through the entire eastern part of the United States.

Can you talk a little bit about Maryland's new invasive plant law?

Kerrie Kyde:
" "In 2011 the state legislature passed a law called the Maryland Invasive Plant Prevention and Control Act. It's part of the Maryland Department of Agriculture. And it did two essential things. It formed what is called the Invasive Plant Advisory Committee (IPAC) which is a group of 11 people who advise the secretary of agriculture on primarily ornamental plants--things that have come in through horticultural channels and their invasivity. And the second thing it did was to give the IPAC two tasks: one was to choose a risk assessment protocol, and the second was to use that protocol to do risk assessment on a whole suite of potentially invasive plants.

So we take the probability from the risk assessment that something is going to be a problem species and we assign it a tier ranking: either tier 1 or tier 2. Tier 1 plants will be banned in the state, no longer able to be sold, transported, produced, introduced, or transferred. The only thing that's not illegal about a tier 1 plant is to actually have it. So if you have a tier 1 plant in your yard it's not illegal.

Can you tell us any of the plants that you know are going to be on that list?

Kerrie Kyde:
"You bet. There are six species right now. The tier 1 plants--that is the ones that will be banned--I didn't tell you what happens to tier 2 plants yet--but tier 1 plants… there's one that doesn't exist at all in Maryland right now. It's called shining geranium, Geranium lucidum. It's a huge problem in the Pacific Northwest forests, and it is a plant in the trade. But it's not currently sold in Maryland and by making it a tier 1 plant we keep it out."

"That's what the law is meant to do, is to prevent. The other two tier 1 plants are fig buttercup, Ficaria verna which is that bright yellow flower that you see all over flood plains, especially forested floodplains, very early in the spring. For the next several weeks it will be in bloom. And the third is yellow flag iris, Iris pseudacorous, which is still sold in the state, not widely sold. Many, many of our Maryland aquatic plant dealers have given it up because they realize it's a problem species. And it has been documented in the same habitat as some of our rare freshwater wetland plants. Tier 2 plants will still be able to be sold, but with very clear bright yellow signage right next to the displays that indicate that this is a problem species."

"There's a QR code on the sign that encourages a plant buyer to check out more information on the plant and look at regulations on MDA's website. And it suggests that you consider alternative plants. What we expect and hope that will happen with tier 2 plants is that the educated public will understand that these are less desirable species, and eventually the demand for these species, will die off and people will have no incentive to sell them."

Read the rest of this series:Find out more:
Invasive Species of Concern in Maryland
Maryland Invasive Plant Advisory Committee
Delmarva's Rare Plants with Wes Knapp Part I
Delmarva's Rare Plants with Wes Knapp Part II
Maryland Department of Natural Resources Wildlife & Heritage Program
Maryland Biodiversity Project
Maryland Biodiversity Project on Facebook
Maryland Plant Atlas