How to control horsetails (equisetum)

Question

I have a neighbor with lots of these horsetails in his yard. (Probaby Equisetum arvense). Where possible I have put six inches of pool liner between his weeds and my garden but they seem unfazed. They will send roots three feet in length under flagstone and come up through a well compacted bed of five/eighths gravel.

One year I couldn't stand it any more and used some roundup or glyphosate. I crushed the stems and then sprayed. It killed the growth but not the roots.

I live in eastern Canada (zone 5a) and have alkaline (ph 7+) soil due the amount of limestone around).

I spend a lot of time pulling the same plants over and over. Are there any effective control methods for horsetails?

Answer 1

You set me off on a research mission too....

The word on glyphosate and equisitum is that you need to treat for several years, possibly, and do it frequently, bruising the growth every time you use it, so it may be that it does work eventually, but people who try it aren't persistent enough. At least 4 treatments a year are necessary, maybe up to seven, depending on growth.

There is supposed to be an organic method of controlling it, which involves digging out, (not by mechanical means) as much as humanly possible, then hoeing off an inch below ground the green shoots that reappear when they're no more than 3 inches high. This is said to exhaust the main roots (at least 7 feet down) eventually, and they give up. Labour intensive, not a quick solution. Same theory applies to the 'grassing over' solution - constantly cutting the grass and the equisitum is said to weaken it over years till it gives up and dies back.

Or there's Kurtail (previously Kibosh), which isn't technically available to gardeners, is for professional use only, but seems to be freely available on E Bay. This product, though, is the one responsible for contaminated horse manure, but so long as horses aren't grazing, or the resulting manure used before at least 3 years of composting has passed, it shouldn't be an issue. It's a contact herbicide, so careful use amongst other planting is necessary, as with glyphosate, but repeated applications are also required, though it is more effective than glyphosate.

Answer 2

I use glufosinate on horsetails, Kochia grass, Canada thistles, nutsedge, and whatever glyphosate won't take care of. It is a little slower, but works very well in the long run. I spray or brush this onto the leaves of the weed on a hot sunny day. I usually wait until the plants' stems are completely dead before pulling. If the plant is very established, it may regrow somewhat. Another application usually does the trick.

Digging the plants out will not help if you are using this herbicide, as it is most effective when applied to the most foliage area, and left until the plant is dead. Also, digging could leave viable root pieces in the soil.

Note: This herbicide is harmful to animals and people, and should be used with common sense, only when absolutely necessary. If you have dogs or children, maybe consider temporarily fencing in the area. I always cover treated areas with plastic mesh, to keep birds out until I pull the dead stems.

Because you are probably not going to spray the neighbors weeds, make sure all the runners between your garden and his are cut, or the plants will not be controlled well. They'll be set back, but regrow from the untreated plants on his side.

I would also suggest a more substantial barrier on the property line. A rigid plastic or galvanized steel edge, at least 12-15 inches (unless your topsoil goes farther than that :) ) should work well. I've seen people use corrugated roofing panels with success, but you have to be sure they are fitted tightly together, so the runners don't find the cracks.

Answer 3

There's a very good reason why they are one of the ancient plants that have existed for 000's of years or are the direct descendants of the pre historic plants, darn it. They prefer moist soil so improved drainage may lessen their enthusiasm for growth. Burn and not composting any you pull or weed will reduce further infections. Hopefully you can get your neighbour on board with control too, which will lessen ingress from that direction. Good luck in your endeavours with this one.

Answer 4

Over the past few years I have found that hand pulling is effective if you start early. As soon as they start appearing wait until they are a few inches tall and pull on the stem as close to the ground or below ground.

It looks tedious but if you are persistent over several years the amount of work is less every year. You cannot get rid of them this way.

Answer 5

I'm a person who has conquered both poison ivy and bamboo. You just have to first pull up all the roots you can find, and then spray it...every single weekend. Use a garden claw to loosen the soil first, that will help you pull up more roots. These are very tough weeds you are dealing with.

Or dry out the area they are living in. They prefer damp soil, like on the edges of ponds.