How can I get rid of "Shiny Geranium"

Asked March 22, 2016, 9:35 PM EDT

I have a large area that is woody, shaded and wet where this plant has taken over and is expanding. What time of year is the best time to fight it and with what. I found a picture of this weed on Oregon Department of Agriculture and they rate it as a B rated weed? But they do not say how to get rid of it.

Clackamas County Oregon

1 Response

Geranium Lucidum, shinning Geranium unfortunately is well established in Western Oregon.

Once well established it is very difficult to eliminate. As a class B noxious weed it is a landowner’s responsibility to contain it however. As with most weeds it is important to take control measures before the plants go to seed. The good news is it appears the seeds may only be viable for several years.

The plants seed in late June through July so March and April are the ideal times to take corrective action. It sounds like your infestation is beyond the small patch solution of hand pulling and digging.

For larger infestations either an application of herbicide or burning with a propane torch (if allowed and safe), or using a sheet mulch for one or two growing seasons should be done before the plants flower.

If desirable grasses are in with the weeds, apply a broadleaf herbicde such as triclopyr ( like Brush B Gon). If the weeds have choked out grasses, a non-selective herbicide like glyphosate (Roundup) can be used. Oregon Department of Agriculture reports a product labeled Finale has been effective. Always consult and adhere to herbicide labels for your safety and the minimum impact to your land.

Please refer to herbicide labels for site specific control information and refer to the PNW Weed Management Handbook for additional information on herbicide use.

Using landscape fabric or durable tarps have shown moderate success if herbicide cannot be safely used. When safe and allowed, using a propane torch several times a year will also contain the problem. Using fire in a wooded area should obviously be done with great care since any fire that escapes control is the liability of the person starting it.

Because the seed bank is established, it should be recognized controlling and eliminating the weed is a several year project. Carefully clean boots and equipment used to avoid spreading the problem to new areas.

If your infestation is a large one, you may also want to consult your county weed person to make him or her aware of the infestation location and consult on best practices for your area.

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