View Full Version : How to kill horsetail

06-21-2006, 07:38 PM
I am a relatively new enemy of horsetail after moving to the Pacific NW. I have tried Roundup and Weed-b-gone and a couple of other things. The Weed-B-Gone lists horsetail and it does kill the above ground portion. But it does not appear to kill the mother plant underground. The underground system keeps putting up new surface plants.

I remove spore pods in the spring before they ripen (you have to check every day - they are incredibly rapid growing). I have been killing the surface plants whenever I find them for the last two years. The theory I am working on is to eventaully starve the mother plant to death. This is my second year of this approach and this years crop is way more than last year.

Anyone know of a way to eliminate these primative plants?


Bob NH
06-21-2006, 08:25 PM

Round 'em up while they are small. Kill! Kill! and Kill again!!!

06-22-2006, 10:43 AM
Man, that looks like a nasty one. Good luck.
We are being slowly invaded by a variety of mustard here in the desert.
Mother nature takes care of most others due to lack of water and extreme heat.

06-22-2006, 11:25 AM
Horsetail doesn't die easily with glyphosate.

Your best bet is a thick, dense lawn.

I'd use a combo of round up and daily weeding until the fall. Then I'd aerate and overseed. Use a healthy dose of starter fertilizer. Grass seedlings will respond well to it; while it does little for the htail. Straw mulch will shade the area, which htail hates.

It's really gotta be a couple-year process to eradicate. But as with most weeds, the best defense is to fill every possible space with a better weed - grass!

Gary Swart
06-22-2006, 12:32 PM
I haven't seen a plant yet that I couldn't kill with Round-Up. Only thing is, it only will kill the existing plants. Any seeds in the ground will grow new plants, so you have to repeat the Round-Up every so often until there are no more seeds, and new seeds may blow in from elsewhere so you're probably never going to be 100% weed free.

06-22-2006, 12:59 PM
Roundup on weeds in the grass is a bad idea , IMHO. For accuracy, you can "paint" it on carefully with a foam brush, or you can grab the weeds with a roundup soaked glove (wear a rubber one inside of that).

I've tried both.

Until you get really good at it, you end up with ugly dead patches.

You're best off killing it mechanically as much as possible and relying on new grass to crowd it out.

06-22-2006, 06:03 PM
I haven't seen a plant yet that I couldn't kill with Round-Up. Only thing is, it only will kill the existing plants. Any seeds in the ground will grow new plants, so you have to repeat the Round-Up every so often until there are no more seeds, and new seeds may blow in from elsewhere so you're probably never going to be 100% weed free.

I have one bird of paradise bush near my septic that has to go.
Didn't think round up was strong enough but I just may try it out Gary.

06-27-2006, 06:40 PM
Thanks for the responses. I have found it more damaged by weedBgone than Roundup. Not sure why, but it responds better to the broadleaf killer.

From what I have gathered in tryinig to find information the underlying root system can be quite deep and difficult to get to absorb poison from sprays. I do not believe grass will stop it. It will come up through mulches and asphalt.

07-07-2006, 08:08 AM
I talked with a colleague who's a genuine expert in weed science, and have some preliminary information; he thinks he knows a real expert in this particular area, and will try to contact him for more info. Anyway, horsetail stores food in a deep root system, so topical herbicides have only temporary effect. The above-ground portion may die off, but the plant will survive and regrow. Repeated applications will ultimately kill the plant, however. Unfortunately, seeds are easily propogated and new plants pop up all the time. (I'm sure this is not news to you.) The most effective herbicide he knows about is glufosinate-ammonium, one trade name "Finale", but it will still require repeated applications.

More info:


Be thankful you don't have this stuff:

http://www.fiu.edu/~chusb001/giant_equisetum.html (http://www.fiu.edu/~chusb001/giant_equisetum.html)

07-07-2006, 12:12 PM
Thnaks. I appreciate the information. Anything further will be gratefully input as well.

I did know about the deep roots. I believe they can be very deep (feet) and fragmenmts will grow. I think some of my infestation is from moving dirt around during construction.

I have some Finale. I tried it a year or two ago and did not see any immediate improvement. I will switch to that and see what happens. I have been told that you should spray in the fall when the plants absorb nutrients as the above ground fronds (?) die back. It seemed counter intuitive to me that the root system would not be absorbing photosynhesis products as long as the plant was above ground.

They are very old plants that have survived a long time. But I ws hopeful that it was because the dinosaurs did not have weed killer. Perhaps frustration with horsetail killed them off. The plant seems to have no natural enemies. Even the 2 pound NW slugs seem to leave it alone.

08-06-2006, 10:15 AM
I also have problem with horsetails in my flower bed. It started from very small spot in wet area of the bed. I was busy with work and neglected to rid them for months and months. Then they spread very fast! We have tried to dig them up and you wouldn't believe - the rhizomes could be a foot long or more! We consulted a master gardener at Center for Urban Horticulture in Seattle and was told the best way to get rid of horsetails is to just pick the part that comes above the ground out as soon as possible. After 4-5 years the plant will run out of energy and won't come back. (She told us this is actually true in her flower bed!) We're trying to do that - I get rid of the horsetails in my flower bed at least once a week. I'm pretty obsessed with killing horsetails and tried to pull the rhizomes out as much as possible too. There was a reduction in horsetails after our first battle of pulling everything out. After that, there seems to be constant number of horsetails coming up still, after about 4-5 months. Good thing is the new ones seem to be smaller and many of them don't have thick stems. Bad news is since horsetails could spread either by rhizomes or spores, I probably have to keep picking them up weekly for another 4-5 years. But I do believe picking them up would reduce the population and might eventually kill them all. Good luck to you!

08-06-2006, 11:19 AM

08-07-2006, 05:36 AM

08-07-2006, 06:19 AM
I have a similar problem with quackgrass (I think it's quackgrass). I've speculated that it might be worth it to lay a plastic tarp down and then poke holes where the weeds are and pull them above the plastic. Then you can (relatively) safely roundup the area.

If it works for hairdressers who dye hair, then why not for weeds?

Anyone ever try something crazy like this? I don't want my neighbors to point and laugh unless it's gonna ultimately work.

08-11-2006, 02:48 PM
I believe weed-b-gone is commonly know as 2,4-D which is a very good broad leaf weed killer, better than glyphosate (roundup). It kills the tumbleweed in my yard without killing the grass. Brand name is Weedar 64, you can find it in the online auction giant (you can't say that e-word here) in the stores area the cheapest, for about $20 I mix it 2oz / gal so that'll make 64 gallons of spray.


05-30-2007, 09:40 PM
I have been attacking them now for several years.

Watch carefully for spore pods in the spring. These things grow very fast. You have to look daily.

Every thing big that comes up I pull it up. Smaller stems, probably from spores or offshoots of the mother plant, I pull or spray.

This year I had only one spore pod. Last year it was over 100. Other patches about a block away had a big crop of spore pods. I figure I am wearing them down. Basically denying them energy and starving them.

Maybe I will win eventually.

04-26-2011, 10:10 PM
Hi Alternety: fellow Washingtonian and horsetail obsessed gardener! I have been struggling with horsetail in my front yard (terraced hillside and adjacent gardens at level) for years. Lots of water issues given that we live on a hillside in Washington, so this doesn't help. The front yard is huge and fully landscaped (more every year). I have pulled out probably HUNDREDS of spores from the a spall rock covered portion of a bank. They come up fully grown under the rocks- they are absolutely not deterred by complete lack of light. We already have probably a thousand plants that have emerged into the yard. We have tried digging up, spraying the beds with extra strength roundup (killed a bunch of the nearby plants), and this year digging combined with 50% glyphosate painted on several test beds. This only turned the really small lacy plants brown (same as always), but the bigger shoots just laugh and emerge green anyway. Right under the soil is a defiant vibrant green.

I am dying to know how your eradication project has turned out. Can you share?

This is a great source of info- tons online if you do different searches on horsetail eradication.
Glyphosate products are often used to suppress horsetail; however, you should expect
regrowth. To eradicate a horsetail stand you may have to make several applications over
several years. In many cases, control of horsetail with glyphosate is inconsistent. Casoron

(dichlobenil) has also been reported to have activity on horsetail. MCPA has been used in
small grains to suppress horsetail. Richardson and Zandstra of Michigan State University
reported control ranging from 77% to 92% with Curtail M
(MCPA + clopyralid) at 3.5 pts/A.
Curtail M
is not labled in the state of Indiana and has a 30-day rotation to field corn, and a
12- to 18-month rotation, depending on organic matter, to soybean.
Peter Sikkema of the University of Guelph, Ontario, has reported more than 80% control (and
as high as 95% control) with combinations of glyphosate and flumetsulam. Flumetsulam can
be found in the product Python.

Best of luck!!!