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Accugrow™ Soil Test Kit
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Weed-Aside™ Herbicidal Soap
Question. Mike: A neighbor planted'running' bamboo as a "natural fence" around his property, and notsurprisingly, it's out of control. The culms are about 12-16 feet high;both plant and root system are invading my property. It also blocks outthe sun and sucks up all the available water so that I can't seem toget anything else to grow in my back yard. I've read that bamboo istechnically classified as a "perennial grass" which means that growingit violates a township ordinance requiring grass and weeds not to behigher than 10 inches. If the township orders it to be removed, how dowe get rid of it safely without damaging the environment? Thank you. ---Curtis inCherry Hill, NJ.
Hello, Mike McGrath: What can you recommend to get rid of thistles inmy garden and lawn? I have tried extreme weeding and professionalchemical treatment, but they're back!!!!!!! Thank you.
---Valerie;, Rockville, MD
Answer. These aretwo of the toughest weeds you can face, especially the bamboo, which'runs' at an astonishing rate and will happily take over acres ifallowed to—although your terminology is somewhat off, Curtis. Thosearen't plants AND roots invading your domain—its one big plant with onegiant honkin' root system that expands to cover the earth likehorticultural concrete a few inches under the surface. Some thistlesform similarly impenetrable root systems. (Val—never let thistlesflower; if you do, then you've got roots and seeds to worry about!)
These are not easy plants to beat, and as Val discovered (Bad girl!),toxic chemical herbicides won't do the trick. Those poisons are good atkilling off single plants, but they don't affect huge underground rootsystems—so don't waste your time, money and life fooling around withthem.
There are three basic ways to do the job well and safely, all of whichinvolve you first cutting the above ground growth to the groundrepeatedly. Cut it all down, allow it to grow again; cut it all downagain, let it grow again, etc. Two, three, four times—the more thebetter to deny the roots their solar energy collectors. In fact, if youjust do this continual cutting for several years, the plants and rootswill eventually die.
For more immediate satisfaction, cut and then do one of the following:
1. To kill a patch on your property alone, mulch,mulch, mulch the entire area with something THICK and HEAVY(sheetmetal, old carpeting…) weighted down with a few inches of soil or woodchips on top. Maybe soak the area with a high-strength vinegar (see #3)first. Make sure the mulch extends a good couple of feet past where theplants were growing. Regardless, the root system will likely sendplants out on a scouting mission and try to creep up around the edges.Be vigilant, and mulch these pioneers and/or spray them withhigh-strength vinegar. Leave the mulch in place for at LEAST a year. Orbetter still, leave it there forever, and make a nice raised bed filledwith 'wanted' plants over top.
2. If the bamboo is spreading to your property from aneighbor's place and you just want to keep it on their side, cut yoursdown and drive barriers deep into the ground at the property line tokeep more from spreading over. Then use high-strength vinegar and/ormulch to kill the roots on your property.
Here's some barrier info from one of our favorite sites, www.Americanbamboo.org (this is alsoa great place to learn more about bamboo—not all types are bad; thereare many well-behaved varieties that grow in tidy clumps): "To preventrunning bamboo from spreading, a "rhizome barrier" two or three feetdeep is essential. It should be slanted outward at the top so that whenthe rhizomes hit the barrier they will bend upwards. A barrier does notstop a running rhizome; it only deflects it. The barrier should projectan inch or two above ground level. Check the barrier once a year, andcut off rhizomes that arch over the top.
"Barriers can be concrete, metal, or plastic. The usual recommendationis high-density polypropylene (40mil or heavier), glued, taped, orclamped with stainless-steel at junctions. This material comes in rollsor as hinged sections, and is available from some landscape suppliersand bamboo nurseries, frequently termed root barrier. More elaboratebarriers with corner posts that hold the material at the proper angleare also available." McG: We don't need more plastic in theworld, so I strongly suggest metal instead of the poly.
Essentially what you're doing here is building an underground fence,and before you can build that fence you'll have to dig a trench to holdit. (Unless you have John Henry illusions, rent a machine to do thejob.) And, if you make it wide enough—say a foot across—that trenchalone will make an excellent bamboo barrier. Even better, turn yourproblem into a water feature! Dig a deep trench in between you and thebamboo/thistle/other superweed and then fill it with water and make ita kind of canal running along your property. Put in some fish and someaquatic plants and you're happening! (Like vampires, these weeds can'tcross over running water.)
3. And then there's the favorite high-intensity weedkilling solution of YBYG listeners, high strength vinegars.
Cut everything down, wait till the soil is bone dry and no rain ispredicted for at least a few days and then, in the heat of the day,soak the earth containing those unwanted roots with one of the productsbelow. (Be careful—you must wear protectivegear, especially safetyglasses.) The high acidity of the vinegarwill lower the soil pH down to something like 3—the surface of themoon. All plant and soil life will die, earthworms and larger creatureswill quickly run or squirm away and that region will become a deadzone. Leave it like that for at least a month—longer if you can. (Andif you fear that 'your' plant has more lives than Christopher Lee in anold Dracula movie, do it again a week or two later.) When you're sureit's really most sincerely dead, raise the pH back up with wood ashesor lime to between 6 and 7 (use teststrips or a meter) and soil lifewill return and the ground will be fertile again—but the roots willstay dead.
"Burn out weed killer" is St. Gabriel's Labs mixture of vinegar andlemon juice; it now also contains clove oil and is called "Burn Out II"(the sequel!)—but this is for normal weeds; it's not strong enough forthings like thistle or bamboo. They recently introduced a doublestrength version called "Poison IvyDefoliant" that should do the job. St. Gabe's products areavailable at retail outlets or direct from them at 800-801-0061;www.milkyspore.com.
"Greensense 20% acidity vinegar"is white vinegar that's four times more potent than the householdvariety. ("You watch the weeds die.") Its available in some retailstores in the Southeast, and Rohde's in Garland, Texas (near Dallas)will ship you a gallon for $11.95 plus $8.50 shipping; call972-864-1934, or visit www.beorganic.com and enter "white vinegar" inthe search function. (There's a photo at www.greensense.net.) Although this stuff is incredibly powerful, it is all-natural—and notall high-strength vinegars are. The folks at Rhode's stress that theirGreensense product is a grain based vinegar, not a petroleum-basedproduct like the Acetic Acid used in photography. Once it's doneits work, a grain-based vinegar will return its nutrients to the earth,and allow life to colonize the soil once again. Chemically producedacetic acid will leave toxic resides that will destroy soil life forperhaps years to come; don't use them.
SAFETY NOTE: All of these productsrequire extreme caution on the users part, especially the 20% vinegar!This is not harmless stuff! Vinegar with such enormous acidity isreally caustic! You have to be careful not to get any on your skin oreyes--gloves and goggles are a must!!!!
And that, dear readers and listeners, is why many of you asked Rhode'sto come up with something a bit gentler, and they did. (And yes, theytell us, it was entirely at the request of YBYG listeners, from whommost of their mail-order sales come! Thank you, Rhode's!) The newcreation is "Greensense 10% Acidityvinegar"; $7.95 plus $8.50 mail order. You'll have to useit more than once (the 20% is like dropping a 'natural nuke' on thoseroots), but it is much safer to handle. "You pays your money and youtakes your choice."
"Greenergy Blackberry & Brush Block",8% vinegar (apple cider or wine) and 5% citric acid, is a West Coastproduct (apparently, wild blackberry vines attack people's cars andchildren out there). You can get a gallon from Professional Turf Centerin Portland for $36 (includes shipping); call 1-800-894-7333
(Regular household 5% white vinegar will only kill 'easy' annualweeds.)
You Bet Your Garden ©2004 Mike McGrath