Sumac spelled backwards is Camus, and it's the plague
March 31, 2014 11:17 AM   Subscribe

I need a sure fire method for getting rid of an acre of sumac plants once and for all.

The sumac have been trying to take over my field for the past ten years. Every year I cut them down in the fall and once again in the spring and they are like Zombies impossible to kill. I trust that some MeFite will have a sure fire method for sumac eradication. In lieu of this I may have to resort to a method I read about on-line. Drive a zinc nail into the base of every plant. Any other ideas? Must be organic.
posted by Xurando to Home & Garden (16 answers total) 3 users marked this as a favorite
Natural way:

Cut them down in the spring after they've done their first flush of growth - then do it again through the season as they push up again. This takes a few rounds of cutting and killing and it may be years before you get them all.

There are herbicides that would also be useful but you're not into that kind of thing (I'm with you on that)

For killing things without herbicide, there's always the putting down fairly thick black plastic sheets and letting the sun bake everything under it. I'm not sure this would work with sumac.
posted by sciencegeek at 11:22 AM on March 31, 2014

Whack them down to ground level, leaving no leaves. Then, cover the area with heavy black plastic (as sciencegeek suggests) Leave it alone the rest of the year and hope for the best.
posted by Thorzdad at 11:39 AM on March 31, 2014

Part of the problem here is that sumac spreads underground by way of the roots left after you cut them down. They actually form large clone colonies this way, spreading by means of new shoots that then spread the roots further, and in turn push more shoots up from those roots. To effectively kill it, you'll have to kill these roots, too. That is in part where the zinc nail method comes in. However, youll go crazy trying to do that.

Unfortunately, sciencegeek's cutting back and cutting back method is the best I know of - you'll also want to pull up any roots you can in the process.
posted by strixus at 11:41 AM on March 31, 2014

Response by poster: Unfortunately, sciencegeek's cutting back and cutting back method is the best I know of - you'll also want to pull up any roots you can in the process.</em

I've done that for ten years, I'm beyond that. I need alternatives when there probably aren't any.

posted by Xurando at 11:57 AM on March 31, 2014

You're going to have a hard time beating Glyphosate aka Roundup or its commercial clones. It's actually pretty safe stuff if you're not a plant. It's only "organic" in the sense of organic chemistry.
posted by GuyZero at 11:59 AM on March 31, 2014 [5 favorites]

Dig it all up, however deep the roots go. I had to do this to get rid of kudzu, and it was so hard but so worth it.
posted by Bentobox Humperdinck at 12:02 PM on March 31, 2014 [1 favorite]

Cut off each plant near the base, and drill one or more small holes into the (small) stump that remains. Make sure that the holes do not penetrate the stump anywhere else. Carefully add concentrated glyphosate to the holes that you have drilled, without spillage. Cover the end of the stump with several layers of aluminum foil, formed to keep rain out of the glyphosate-filled cavities.

I've been successful at killing siberian elm suckers using this method, which spreads by roots. Choose your drill bits so they are proportionally smaller than the diameter of your stem (I use a quarter inch drill bit for a half inch stump). Drill them in at least as deep as the diameter of the stump. It works best in the spring, during times of growth.

As for "organic", I would argue that glyphosate is much better than a "zinc nail". It's more effective, biodegrades readily, has a much shorter half-life (40 to 100 days), is almost nontoxic to arthropods, bacteria, fungus, mammals and birds. It binds tightly and does not migrate in soil to spoil water resources. It does not bio-accumulate and is non-volatile. You can read more about it here:

Nails present a puncture hazard to wildlife and livestock (if you've ever pulled a nail or screw from a sheep or horse's foot, you wouldn't apply them to your landscape).

If you are not familiar with glyphosate, read the label carefully. Don't buy anything labelled "Roundup", as that is a trademark owned by Monsanto and nowadays it contains other much more toxic and rapid herbicides. You want something that contains only glyphosate as a sodium salt.
posted by the Real Dan at 12:29 PM on March 31, 2014 [6 favorites]

There's something about the timing of cutting it back. Doing it in the fall or winter is the least effective time - the plant is storing energy then and is perfectly happy to lose trunk etc and just regrow everything in the spring. You want to let it use up all of its stored energy in that first push of growth in the spring, then before it has time to build up more, hack it back. Then let it do that again and hack it back again.

And black plastic.

The herbicide I've been hearing about that you paint on the tree is Pathfinder. I've not used it myself and don't know much about it other than that it works. Completely unfamiliar with the safety issues.

Stuff like this is hard to do. Where I work we have a few acres of Japanese knotweed, several acres of artemesia, a fraction of an acre of phragmites, akebia everywhere, those invasive roses, pachysandra coating hillsides, Chinese bittersweet, and the list goes on.

I have been involved in trying to kill sumac - mainly for the first step of the process, the cutting down. I did some in the early spring (we didn't have a choice on our timing unfortunately) and during the spring thaw, it was easier to pull roots out of the ground. We followed up with cutting it down 2 or 3 times in the season. I don't know how it looks right now - I could ask my former coworker but it may take a while for an update.
posted by sciencegeek at 1:33 PM on March 31, 2014

I trust that some MeFite will have a sure fire method for sumac eradication.

Uhh. . . fire? Any reason you can't just burn the stuff?
posted by valkyryn at 1:54 PM on March 31, 2014

Response by poster: At this point I'm still leaning towards the nails though doing a cut other than the spring or fall might be effevtive. Pathfinder sounds very toxic and I d like to avoid chemicals if possible. There are no farm animals so Im not worried about damage or injury from the nails.
posted by Xurando at 3:35 PM on March 31, 2014

I don't want to discourage you too much but please do get rid of the notion that a zinc nail is somehow more "organic" than glyphosate.
You're essentially going to poison the ground with a (not so heavy) metal.
Zinc is toxic for parrots (just as an example).
Zinc and glyphosate share the same warning symbol: N = dangerous for the environment. The symbol is a dead tree and a dead fish.

" Levels of zinc in excess of 500 ppm in soil interfere with the ability of plants to absorb other essential metals, such as iron and manganese."

Glyphoshate decomposes in a well understood manner. Zinc has to slowely dissolve and get washed out over time which is probably highly dependant on soil chemistry.

If you do not want to do the heavy work, heat treatment and sunlight deprivation, chose the appropriate chemical treatment.

(Zinc of course does also serve some beneficial small amounts.)
posted by mmkhd at 5:26 PM on March 31, 2014 [2 favorites]

Sumac root suckers can live underground and resprout for three years (or possibly more). I doubt you could eradicate it will black plastic; you can't eradicate it with fire (it will resprout with vigor). Your best bet is either foliar spray of herbicide or a cut/basal bark application of an oil-based herbicide. Sumac is strongly affected by triclopyr, which is available in both water and oil soluble forms. It eventually decomposes to carbon dioxide. It will degrade in sunlight. Just keep it out of waterways. Plan to apply herbicide once a year for at least three years. You can minimize release into the environment by using the cut/basal bark application method.

BTW, glyphosate, should you choose to use it, is far more effective applied as a foliar herbicide than as a cut/basal herbicide. It is absorbed through foliage and transported through the plant by phloem. It accumulates in meristem tissues, where it ultimately disrupts amino acids that are needed for protein synthesis. It's not considered particularly effective against sumac.
posted by oneirodynia at 7:55 PM on March 31, 2014 [1 favorite]

In case you're reconsidering the chemical angle (or even if you're not!), you might be interested in A Prairie Haven, a photo-rich, quite extensive blog about a couple's native prairie restoration projects on their property in Wisconsin. They named one of their prairies Sumac Prairie, and the technique they employed on the sumac there in the fall of 2006 seems to have proved effective. Also see Hand Cutting and Treating Brush. I hope the before and afters are encouraging!
posted by Leona at 8:36 PM on March 31, 2014

>glyphosate, should you choose to use it, is far more effective applied as a foliar herbicide
> than as a cut/basal herbicide.

True and correct.

I treat coyotebush (Baccharis pilularis) this way, in the late fall, and by spring I can kick their rotting bases out of the ground. The nice thing about the drilling and filling is that even with the reduced effectiveness of glyphosate in a non-foliar application, it still works pretty well when there is a little reservoir of it right in the stump. I think even non-optimal application of glyphosate would beat galvanized nails.

I have painted glyphosate onto smooth-skinned trees that don't have a lot of "corky" bark, like Ailanthus altissima, or Tree of Heaven, and that worked pretty well. I've heard you can frill the bark on the stump, or on the uncut stem, down to the phloem,and then paint the concentrate onto the exposed tissue, but that's been too much work for me.
posted by the Real Dan at 9:30 PM on March 31, 2014 [1 favorite]

A little searching gave me Avenger AG Burndown.

You should be able to search for OMRI certified herbicides and then make sure they are allowed by your certifier for organic production.

Looks like most are intended for foliar application so you might do best to hold off on the Spring mowing.

Best of luck.
posted by The Violet Cypher at 1:28 PM on April 1, 2014

Response by poster: So despite misgivings I chose to use the glyphosate today (Roundup). I dressed like I was entering a nuclear reactor and used an irrigation syringe I squirted a few drops on each cut stem. the process itself was pretty smooth. I am however at a loss as to how to dispose of the excess Roundup which is now inside two trash bags along with mask and the gloves. Now I have to wait and see if the whole process worked.
posted by Xurando at 2:26 PM on April 25, 2014

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