The mulched flower beds w... - Ask Extension
The mulched flower beds with other flowering trees, shrubs and ground cover (vinca) all around my property have been overtaken by an (annual) invasive...
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The mulched flower beds w... #274116
Asked August 30, 2015, 10:55 AM EDT
The mulched flower beds with other flowering trees, shrubs and ground cover (vinca) all around my property have been overtaken by an (annual) invasive grass-like weed that a local nursery indicated is stilt grass. This is not a problem in the lawn. Please see the accompanying image. Is that the correct identification? If it is stilt grass or something else can you please suggest a way(s) to eradicate this invasive species? Thank you for any assistance.
Montgomery County Maryland
Expert Response
You are correct that this is the relatively new and invasive Japanese Stiltgrass. (We are assuming your photo color is off? It looks white but is green)
You must have a nice, think lawn cover if you have not found it there yet. It grows all over, wherever it finds a open soil.
You are correct that it is an annual. It is very easy to pull with shallow roots, so that is the least toxic method of control. It is probably easiest in flower bed areas.
You should attend to this before it goes to seed. Each plant can produce up to 1,000 seeds, which are viable in the soil for up to 5 years.
In other areas, an herbicide containing the active ingredient glyphosate is helpful. This is a non-selective and will kill any green tissue it contacts, so be careful.
Since it is an annual, you can use a spring pre-emergent to stop it's germination next year. Trifluralin (the active ingredient in Preen) is one, and though you can transplant into it, you can't seed flowers into it, as their germination would be blocked as well.
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You must have a nice, think lawn cover if you have not found it there yet. It grows all over, wherever it finds a open soil.
You are correct that it is an annual. It is very easy to pull with shallow roots, so that is the least toxic method of control. It is probably easiest in flower bed areas.
You should attend to this before it goes to seed. Each plant can produce up to 1,000 seeds, which are viable in the soil for up to 5 years.
In other areas, an herbicide containing the active ingredient glyphosate is helpful. This is a non-selective and will kill any green tissue it contacts, so be careful.
Since it is an annual, you can use a spring pre-emergent to stop it's germination next year. Trifluralin (the active ingredient in Preen) is one, and though you can transplant into it, you can't seed flowers into it, as their germination would be blocked as well.
cm
