Sunday, November 4, 2007

Landscape and Turf - Controlling Bamboo

I recently received several questions on controlling bamboo. The following is an article that I wrote for our Ornamentals Hotline on the subject.

Bamboo has caused many disputes between neighbors due to the propensity of running types to invade adjoining properties. One recommendation is not to use invasive types of bamboo but plant clumping types such as Chinese Mountain Bamboo or Umbrella bamboo instead. Unfortunately, many clumping types are not well adapted to our Delaware climate. If a spreading type such as a Phyllostachys species is desired, then containment is necessary, especially if near a property line. A barrier made of metal, concrete, plastic, fiberglass, or treated wood should be installed at least 2 feet deep and slanted at an angle outward. This will deflect the bamboo rhizomes so when they hit the barrier they will turn upwards and the shoots can be controlled (physically removed) when they appear above the barrier. Inspect barriers at least 2 times a year for these escapes.

If bamboo has escaped, first, trench or use a spade to cut the rhizomes in the invading area off from the mother plant. Then cut the stand to the ground and allow to regrow. Frequent mowing will control bamboo so consider converting the area to turf. If the invaded area is in landscape beds, control is more difficult and involves physical removal of the rhizomes or herbicide treatment. Herbicides are limited in their ability to control bamboo. Czarnota and Derr (U Ga and Va Tech) conducted experiments on two Phyllostachys species. They found that “MSMA, quinclorac, dithiopyr, clethodim, fenoxaprop, and sethoxydim did not control either species” tested. “Glyphosate, glufosinate, and fluazifop significantly reduced bamboo-shoot fresh weight, although regrowth occurred after a single application.” In this same research, Bamboo control with dichlobenil (Casoron) was less than 23%. Glyphosate and imazapyr provided 76% and 98% bamboo control, respectively, at 58 weeks after treatment. Imazapyr (Arsenal, Sahara) is limited to use on forestry sites and right-of-ways. For horticultural uses, repeated spot applications of glyphosate (Roundup, others) will give the best control. However, as many as 4 applications may be needed.

To see pictures from the bamboo control research mentioned above go to the 9/4/07 post in the archives on this blog.

Article by Gordon Johnson, Extension Horticulture Agent, UD, Kent County

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