One man's weed is anothers prize plant. Suprisingly half the plant species growing in NZ are not native. In addition 70% of invasive weeds start of as introduced garden ornamentals. Tobacco weed is a good example being introduced in the late 19th Cent. as a garden plant. It is a fast growing plant, produces many seeds and produces a cover dense enough to prevent other plants from growing beneath it. Environment Waikato have a list of weeds that landowners are required to destroy. There are 38 species in this category and also a number of plants that may cause problems in the future. Actually you can knock one of that total. The Coromandel has been given a free pass for Mexican Devil Weed. It would be an imposible task to eradicate it now as it is so widespread. The full list can be found on http://www.ew.govt.nz/
Control of Tobacco weed is fairly straight forward. Small plants can be pulled up by hand. Chopping larger plants down does not work as they will regrow. The following method comes from Environment Bay of Plenty-- http://www.envbop.govt.nz/ .
Make a downward slash totally around the trunk of your tobacco weed. Do it within 5-10 cm of the ground. Then pour in undiluted weedkiller to the point of runoff. Glyphosate (Roundup), Tordon Gold or Amitrole are effective. If you do this on a standing bush, rather than chopping it down, it will not clutter the ground up below. Access will be easier when you visit the site later to pull up any seedlings that may have germinated.
Is Mexican Devil Weed newish (given that I haven't lived in NZ for nearly 10 years now)? The name doesn't ring any bells.
ReplyDeleteMexican Devil weed seems to have been around for a while.In fact in 1958 a Gall Fly from Mexico was introduced as a form of biological control. It produced swellings on the stems in which the next generation of flies developed and this slowed the plant down quite a bit. Until, that is, an Australian wasp started to parasitise the gall fly larvae. I have looked for some pictures to include and the best plus some info is at www.envbop.govt.nz/weeds/Weed300.asp Hope that this helps.
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