Resistant Horsetail invasion - help needed

Asked June 17, 2013, 1:41 PM EDT

I have 2 flower beds that have been infested with horsetail. I Have tried 3 rounds of round-up several seasons in a row, I have also switched out the soil twice over a 3 year period. It has totally taken over the bed. Last fall I had the soil dug out again, and removed the plants, put a weed blocker fabric on it, and now I have 2 beds full of nothing but horsetail. Last fall I was talked out of putting on a chemical that will kill everything, because I was told that taking out the soil and the fabric would take care of it. I was also told that if I cover the area up with sod it would just come through the sod. Is there anything that will eradicate this? I have found a few that have popped up in different beds, are they going to get worse and if so how do I stop it? I would swear that Round-up is like giving it vitamins, so I am hesitant to use more over worries that I am making it resistant. Anything you could offer would be greatly appreciated. Thank you in advance.

Oakland County Michigan weed issues

1 Response

Hello, Horsetail is very difficult to control as you have experienced. The creeping rhizomes (horizontal underground stems) form an extensive system going as deep as 6 feet below the soil surface.. New shoots can emerge from depths of 3 feet or more. The small tubers produced along the rhizomes are capable of surviving long periods in the soils and new plants can arise from both rhizome fragments and tubers. Roundup is not considered a good consistent control option. Here are a few links about managing horsetail. They are all based on current science. Please read through all of them to gain a better understanding of what will and will not work.

"Due to it primitive vascular system, horsetail does not translocate postemergence herbicides as well as other plants. Therefore, the extensive root system will push new top growth soon after burndown. Glyphosate alone or in combination with 2,4-D or diquat can provide up to six weeks of control. Repeat applications will almost certainly be necessary. The commercial premix combination of glyphosate plus diquat has performed very well in demonstration plots at MSU. Dichlobenil has also proved effective to suppress populations for up to one year.
Disclaimer: Always read, understand, and follow the label directions. Mention or exclusion of specific products does not represent an endorsement or condemnation of any product by Michigan State University."
According to the Univ. of Wisconsin, MCPA can be an effective chemical control. MCPA is listed under 'active ingredients' in many weed control products---
"Repeated applications of MCPA reportedly reduce horsetail infestations and would be safe to perennial grasses such as bluegrass and pasture grasses."
Articles at other links---

You still need to be persistent and patient to gain control over this. If you still have questions please don’t hesitate to write back.