Anderson County Extension answers lawn questions about American Burnweed

The Anderson County Extension has been bombared with questions about the American Burnweed. American Burnweed, better known as Fireweed, is a particularly obnoxious weed in the early spring. It usually appears in April, seemingly out of the blue, and can look like its literally taking over your yard. It has big fat leaves that really stick out like a sore thumb in your in-the-process-of-greening-up lawn.

Fireweed comes from seeds blowing around in the spring storms. Fireweed produces small white or greenish flowers that go to seed like dandelion puffs, and then they go everywhere. The seeds float down and root in the thatch layer of your lawn. (This is little pieces of dead grass, leaves, and other lawn detritus thats on the dirt at the base of your grass.)

Since its not rooted into the soil, it pulls up very easily, and when the weather heats up, and you start mowing regularly, it will dry up and die. Until then, we can treat it with a good post-emergent broadleaf herbicide in April and May.

Post Emergence Control:

A three-way herbicide may be used on Bermuda grass, Zoysia grass, Centipede grass, St. Augustine grass and tall fescue. The active ingredients of a three-way herbicide often include the following broadleaf weed killers: 2,4-D, Dicamba, and Mecoprop (MCPP). Examples of a three-way herbicide are Ferti-lome Weed-Out Lawn Weed Killer with Trimec, Bayer Advanced Southern Weed Killer for Lawns, Spectracide Weed Stop Weed Killer for Lawns, Southern Ag Lawn Weed Killer with Trimec, and Lilly Miller Lawn Weed Killer Concentrate.

Note: Herbicides containing 2,4-D should be applied at a reduced rate on St. Augustine grass and centipede grass to prevent damage to these lawns. If a second application is needed, apply the herbicide in spot treatments. Repeated applications of a three-way herbicide should be spaced according to label directions.

In addition to three-way herbicides, Metsulfuron (such as in Manor and Blade) can be used for Fireweed control in Bermuda grass, Centipede grass, St. Augustine grass, and Zoysia grass. Metsulfuron is packaged for landscape professionals.

Due to the cost and application rate of this selective herbicide, it may be more practical to hire a landscape professional to apply the treatment. A non-ionic surfactant (such as Southern Ag Surfactant for Herbicides) is required at 2 teaspoons per gallon of spray mix for best control. Do not apply Metsulfuron to lawn if over-seeded with annual ryegrass or over-seed for 8 weeks after application. Do not plant woody ornamentals in treated areas for one year after application of Metsulfuron.

Do not apply Metsulfuron herbicides within two times the width of the drip line of desirable hardwood trees. Do not apply Metsulfuron to Fescue Lawns.

There is no pre-emergent for Fireweed, because it doesnt root in the soil in the first place.

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Anderson County Extension answers lawn questions about American Burnweed