Our Townhouse Complex Gardens in Cloverdale are being taken over by "Equisetum arvense" horsetails. Can you inform us how we can get rid of them without damaging other plants and vegetation in the same area? I have heard double distilled vinegar will work. My concern is spraying that amount of vinegar in such a large area when mixed with rain. Will it damage what is in the same area with seepage? Looking for some advise. Regards Garnet Smith
Field horsetail is a chemical-resistant coal age relict, the only plant so far able to grow on the arsenic-laced rubble piles remaining from the Tacoma Smelter in Ruston, WA. Where there are other plants that would be damaged by vinegar applications you have to just keep hoeing the weed off or shade it with weed barrier. However, in the latter instance anyplace there are openings - even small holes - it will come through. So each spot where there is a gap in the barrier around a garden plant the horsetail will come up in the same space. And if the beds are already fully planted it really is not feasible to put the barrier down at this point. So the best option may be to plant densely with ground-covering shrubs tall enough to mostly exclude the sprouts of the horsetail. This approach would also reduce the need for controlling other kinds of weeds. In order to not be having to extract unwanted plants from inside mats of woody stems shrubs growing at least 2 ft. high need to be used, and the need for weeding will not be reduced to the lowest possible level until the planting is fully developed. Otherwise you are left with putting the infested areas in turf or solid pavement, such as concrete (with no cracks) that the plant cannot come through.
Cloverdale eh? Is it poor drainage? Is it a new complex? They are prone to horsetail infestation due to soil compaction and cheap landscaping installation. Much of that area has heavy soils that remain wet for long periods. Horsetails will thrive in that kind of environment. My suggestion is to talk to a knowledgeable local landscape contractor & possibly spend money on sub-surface drainage, top dressing with sand/compost mix & any other ways to improve drainage, & lighten & aerate soil. This has worked for me in the past, both on my own properties & those I managed. Takes a few years to get it under control.
Heavy soil apparently not required as I've had field horsetail invade a sand bed as well as grow to the top of a pile of arborist wood chips, from the soil several feet beneath. Down here one of the common ways to get it may be via infested topsoil piles coming from dealers, I have seen these with a fringe of the plant on the less disturbed back side more than once.
I completely agree about "topsoil" as a source, particularly in new construction. However, I stick with drainage and soil improvement as the best long-term ways to both encourage the growth of other plants & to gradually eliminate the horsetail. Perhaps a healthy soil fauna & flora is part of the solution & would explain why this plant thrives in disturbed & marginal sites?
Another option: stop trying to fight it, and accept it as an interesting native plant that has its rightful place in your plant community. Have a read of this thread for some ideas.
