Controlling Horsetail

By Carol Sitarski

Master Gardener Volunteer

One of the big challenges for gardeners is Equisetum spp., also called horse tail. It’s a perennial plant that grows 8-12” tall. They have the look somewhat of a primitive Christmas tree. Horse tail has a fast growth, it spreads quickly, its reproduction is asexual, a few horsetails plants, this can be “harmless-looking plants” but it can quickly cover a large area. These plants are virtually almost indestructible.

New shoots appear from scar tissue on roots, so pulling is useless. The roots can go over five feet deep, so forget digging them out. Trying to smother them with tarps, mulch, etc. only creates more of a habitat it loves which is dark, damp, and acidic. Besides all this, horsetails are impervious to all but the most toxic chemicals. The top growth will die but roots are unaffected. So, the question is “how to get rid of them?”

The first step is to check your soil for any drainage problems and correct them. Second, remove mulch or plastic from the soil (you don’t need to dig up your plants) then apply dolomite lime at the rate recommended on the label/package, and add water. Wait at least two weeks before adding fertilizer, this because lime and fertilizer tend to cancel each other out when applied together. The next step is to apply at least two inches of organic fertilizer such as cow, horse manure, or homemade compost. The best time of year is in the fall so all nutrients will incorporate into the soil over winter months. It is not recommended for you to dig or roto-till this in as digging will create more plants.

Now you need to be patient and wait for the soil to improve its dampness, PH, and fertility. This may take over a year and may need to be redone again if plants still come up. Around April check the surrounding area for any leafless sprouts with pink/yellowish domes and cut these off. These are the spores for new plants, do so carefully placing them in a plastic bag and dispose in the trash, do not add to compost pile. Good luck and “Remember patience is a virtue.”

References:

Carol Hall. (2004). Controlling horsetail. Gardens West Magazine. Swansons Nursery and Garden Center. Seattle, WA, USA.

Last updated December 20, 2023