Weed Removal

Asked November 8, 2019, 2:16 PM EST

Suggestions regarding the removal of the weed Field Horsetail, equisetum arvense L., Equisetaceae. I have identified the weed through the Michigan State "Got weeds Remove them before seed" Thanks for your help. Any treatment will be implemented next spring.

Leelanau County Michigan

7 Responses

Field horsetail is a perennial, spore-producing plant with a prolific rhizome system that can grow to a depth of 6-10 feet or more. Field horsetail has two stem forms. The reproductive form appears as erect, unbranched, white to brown fruiting stalks (stems) which emerge in early spring and bear terminal spore-releasing cones. These stems wither and die back after spore release. Vegetative stems are green, branch in whorls and give the plant a bottle-brush appearance. These stems emerge later in the spring and should not exceed 2 feet in height. Field horsetail is a common weed of landscapes, orchards and nursery crops. It is often found in areas of poor soil drainage or where the water table is high. It can also grow particularly well in sandy, gravely soils or neutral or slightly basic soils. Once established, field horsetail can tolerate many habitats.

Control. Anything that can improve surface and subsurface drainage may help reduce the competitive nature and incidence of field horsetail. Mechanical control options include hand pulling shoots and what rhizomes/roots you can dig up. Plants can spread if rhizomes are chopped and not removed, therefore try to get as much as possible and dispose of in the trash, not in compost. By mechanically removing the parts you can get to you may be able to starve the extensive root system over time, but it will require constant vigilance over several years. If soil removal is an option, soil would need to be removed to 6 feet or more. If that is not possible, placing a geotextile fabric in a shallowly excavated area before back filling with new soil would prevent rhizomes from entering the bed. Fabric must be placed on the bottom as well as the sides of the hole.

Chemically treating the plant with herbicides is problematic because of the biology of the plant. The high silica content of the stems limits herbicide absorption and extensive root system often results in regrowth. Field horsetail is tolerant to most herbicides used in the landscape. Homeowners have had some success with repeated applications of glyphosate (the active ingredient found in Roundup Weed and Grass Killer, and other generics). Glyphosate will injure desirable plants with which it contacts as a spray or drifted spray. Remember, always read and follow labeled directions and be sure that the chosen product does not contain additional active ingredients as this could impact the ability to replant in the area.

If there is visible water located near the site at the time of application or it is along the shoreline of the Great Lakes or Lake St. Claire a permit is required prior to making a herbicide application; contact the MI Department of Environmental Quality (DEQ) Aquatic Nuisance Control Program Staff at (517) 284-5593 for more information. Also, a list of approved aquatic herbicides needs to be consulted on the MI DEQ website (https://www.michigan.gov/documents/deq/wrd-anc-approvedherbicides_445623_7.pdf). Glyphosate products are available on that list.

Thank You for the vast and complete answer although it is a bit disheartening! The weed is in a cedar swamp with high water table. In addition the growth is close to Glen Lake which may prevent glyphosate. To remove by hand and dig would be very arduous due to the extent of the growth and the cedar tree roots. An alternative is to plant something that would crowd out the weed. Such suggestions include Eutrochiun purpureum Joe-Pye weed, Monarda didyma L Scarlet Beebalm or Pycnanthemum tenuifolium Narrowleaf Mountainmint. I believe these all require full sun which would not be available on a regular basis. Another plant is Sweet Woodruff which grows in shade. Thanks again Your reflection on the above would be appreciated. Chuck A

If you environment is shaded that will make finding a "replacement" species more difficult. As far as the species you mentioned sweet woodruff (according to Michigan Flora) doesn't appear to like wet habitats, so I don't think that would probably be a good species to replace the horsetail with. Also, horsetail is a native species to Michigan and sweet woodruff is not, so depending on your goal that might not be desired either.

What is your main goal in removing/replacing the horsetail? I ask that because the definition of a weed is in the eye of the beholder so to speak. And how many hours of full sun would you say this area received? Once I have a better idea of these things I may reach out to some other people to find options for other competitive species that may help suppress it.

My main goal is aesthetics. Previously this "plant" was not growing in the current area. Backfill of wood chips were brought in and the plant appeared. As to sun, it is filtered most of the day due to cedar trees. Any direct sun is 4 hours at best, 2 in the am and 2 in the pm as the sun moves from east to west.
Thanks again for your counsel and help.
Chuck A

I reached out to one of our aquatic plant specialists, but she said it was a little outside of her expertise, so she is supposed to be checking with some of her colleagues. When I hear back I will re-post.

Thanks for your help and persistance.
Chuck A

Chuck,

Ok, I just heard back from Jo Latimore. She didn't hear back from the network of people she asked about a competitive plant to replace the horsetail, so here are her suggested resources that may lead you to a plant that fits your environment and desires.

"Michigan Natural Shoreline Partnership - "Plants for Inland Lakes"

Minnesota's "Plants for Stormwater Design" guide lists many plants that are tolerant of wet conditions, and gives detailed descriptions. "

I'm sorry we couldn't narrow it down any further.

Best wishes!