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Mr. Smarty Plants - Use of chemicals for eradicating invasive plants

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Thursday - April 24, 2008

From: Driftwood, TX
Region: Southwest
Topic: Invasive Plants
Title: Use of chemicals for eradicating invasive plants
Answered by: Nan Hampton and Barbara Medford

QUESTION:

Re: Round Up We are extremely reluctant to use any chemical agents in our yard (or around our home) due to environmental & ecological reasons... However, we are becoming inundated with several very invasive plants which we are having trouble eradicating. Round Up has been recommended to us for this purpose, but we are still very concerned about our trees & wildlife. We have heard some horror stories about such use, as well as some reassurances as to safety 'if used carefully & according to instructions without any breeze'. We are dealing with poison ivy, something which may be commonly called cat's claw vine, & several other invading nuisance somethings as yet unidentified. Would you recommend any alternative treatments for this purpose? Any "real" information about Round Up & any help you could offer as to ridding ourselves of volumes of problematic plants would be sincerely appreciated by me & my family who would love to use our large yard safely! Many thanks for your wonderful service & care for our native yards.

ANSWER:

Ah, the first signs of Spring-requests for HELP with poison ivy, briers, and other noxious (even if they're native) weeds. We fully understand why there is so much confusion about the use of Roundup and other herbicides. You go into a garden store and ask a clerk who usually works in the geraniums what to do about those plant monsters. He reaches over and picks up a can of herbicide and hands it over. If you actually read and follow the instructions, there really isn't any problem, but understanding what you read and following those instructions are a real puzzle. From Wikipedia, we copied this statement about the use of Roundup: "The active ingredient of Roundup is the isopropylamine salt of glyphosate. Glyphosate's mode of action is to inhibit an enzyme involved in the synthesis of the amino acid styrosine, tryptophan and phenylalanine. It is absorbed through foliage and translocated to growing points. Weeds and grass will generally re-emerge within one to two months after usage. Because of this mode of action, it is only effective on actively growing plants; it is not effective as a pre-emergence herbicide." The lessons from this are: (1) these are not good chemicals to be spraying around, breathing in, or letting get into the water supply; (2) it does not differentiate between good plants and bad plants and (3) you're going to have to do it all over again in a month or so.

One of our Mr. SP team says she got after poison ivy by wearing all-over protective clothing and pulling the plant out by the roots. She still got some rash at her wrist where the sleeve joined the glove of the suit. She also said she used Roundup and brushed it on sprouts and leaves when they first came up. Because this is such a popular subject, we are going to refer you to some previous answers by Mr. Smarty Plants.

First, previous answer on the cat-brier, probably Smilax bona-nox (saw greenbrier). Next, previous answer on poison ivy, Toxicodendron radicans (eastern poison ivy).

Finally, the Lady Bird Johnson Wildflower Center advises neither for nor against any herbicide. If you Google on Roundup, you will get severely biased opinions both for and against its use. About all we can say is there is no such thing in Texas as a day without a breeze, so random spraying seems very dangerous. Trying to center a spray on a vine without damaging the tree or other vegetation behind it is not very likely. We are not chemists, but we don't want you spraying a mist that you, your children and the neighbor's dog will all be breathing. And, if you will note in the quote from Wikipedia, it will all have to be done over in a month or so. Grit your teeth and pull the stuff out, and prepare yourself to keep pulling it out, and digging out the briers, and keeping underbrush cleaned up so you can see it when it first emerges. Sorry, that's part of the experience of gardening.


Smilax bona-nox

Smilax bona-nox

Toxicodendron radicans

Toxicodendron radicans

 

 

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