By: Sandy Feather ©2010
Penn State Extension
Q. I unwisely planted a small clump of bamboo in my yard. Needless to say, 10 years later it has become a monster. Is there anyway to eliminate it? It will soon take over my garden and the yard next door.
A. You are not the first and will not be the last to be seduced by bamboo. It is an attractive plant and it works well for a quick privacy screen. But as you have learned, that rapid growth is a double-edged sword. For those of you thinking that you would like to plant bamboo, stick with the clumping forms and avoid running bamboo 'like the Plague!' Getting rid of running bamboo is a process, not a one-shot treatment. It is likely to take several years and tenacity on your part to get rid of it completely.
Using a combination of methods, rather than relying on one tactic, increases your chance of success. Non-chemical controls include digging and mowing. Although digging out the stout rhizomes (underground stems) is no one’s idea of fun, it can be done. If you are almost fanatical about digging out re-sprouts whenever they appear, you will gain the upper hand.
Although bamboo is grass-like, it is not a true grass, and it does not tolerate repeated mowing like your lawn does. A combination of digging and frequent, short mowing will eventually exhaust the carbohydrate reserves in the roots and rhizomes.
Another approach to bamboo control is to allow it to grow until late June, then cut it back to four to six inches. This will force the bamboo to spend some of its carbohydrate reserves and will weaken it somewhat. It will also result in shorter plants that are easier to spray. Allow it to re-grow, and then treat it with a systemic herbicide from late August to mid-September. Allowing it to re-grow provides a larger leaf surface area to absorb the herbicide.
At that time of year, plants are translocating the products of photosynthesis from their leaves down to their root systems for the winter. They readily absorb systemic herbicides then and move them down to the roots for more complete control. Herbicide applications made in the spring when plants start actively growing – and the movement of sap is upward and outward – are much less successful, as are those made to drought-stressed target weeds.
Glyphosate is the common name of the active ingredient in the non-selective, systemic herbicide Round Up®. If you can find Roundup Pro® or one of the 41 percent glyphosate knockoffs like Eraser® (Agway), it would probably be more effective than the homeowner formulations you typically find at the big box stores. The fact that glyphosate is non-selective means that you have to use it with care near plants that you value because it can kill or injure almost any plant.
Demonstration trials by the University of Hawaii Cooperative Extension showed 80 percent control of bamboo using foliar applications of glyphosate. Since bamboo is tough to control, use the highest application rate allowed by the label of the glyphosate product you are using. It will require more than one application to obtain complete control. Once you knock it back to a manageable size, a combination of digging, mowing and well-timed spraying should keep it on the ropes.
Commercial applicators have more options, at least on non-residential sites. For ornamental plantings, a combination of dicamba (Banvel) and clopyralid (Stinger) produce good results; in turf areas, dicamba and Confront (triclopyr and clopyralid) are recommended. Repeat applications are required for complete control. Clopyralid is no longer registered for use on residential properties because it does not break down in the composting process. Dicamba must be used with great care around trees and shrubs because it can be absorbed through the roots and damage valuable plants. Although these are not restricted use products, they are not readily available to home gardeners.