Growing Green: Bamboo take over
Bamboos are perennial members of the grass family and are often one of the most difficult to control escaped ornamentals.
They are distinguished from other grasses by their woody stems, branched growth, and often large size. They can grow anywhere from one to 70-feet tall.
While often considered beautiful, bamboo can quickly turn into a homeowner’s worst nightmare if not properly maintained. Many municipalities in the Lehigh Valley are banning the planting of bamboo.
Non-native invasive species such as bamboo were introduced to decorate homes and gardens. Over the years, they have escaped cultivation and have infested natural areas.
These non-native plants have an advantage over native species and can easily out-compete them for habitat because they grow in environments that lack natural controls such as diseases and predation. This causes an imbalance in the ecosystem and threatens biodiversity of the area.
There are about 1,200 species of bamboo with many of these being sold in the nursery trade. There are two basic types of bamboo: clumping and running.
Clumping bamboo species grow in large clumps and are relatively slow in spreading. Their root system can be quite large and compete with surrounding plants. This type can often be removed by digging up the offending plants.
Running bamboo species, among the more popular types sold at nurseries, are the more invasive, spreading types. Running bamboo can be very problematic once established, as they spread by thick, tough, underground stems called rhizomes. The rhizomes can spread more than 100 feet from the mother plant and are very resistant to adverse environmental conditions and most herbicides.
Every effort should be taken to control a bamboo infestation in its entirety. Because bamboo is so aggressive, it can re-establish rapidly if any small section is left untouched. Homeowners with bamboo infestations must be patient, as this weed requires an intensive control program over several years.
The first step in controlling bamboo should be to remove as much of the root mass and rhizomes of the plant as possible. This can often be done by hand with small infestations, but larger problem areas may require the use of power equipment.
Containment is also a fairly effective method of controlling bamboo, but must be monitored regularly. Because the rhizomes of bamboo are fairly shallow, growing less than one foot deep in the soil, a barrier made of concrete, metal, plastic, or pressure-treated wood installed about 18 inches deep has proven to be effective.
Bamboo rhizomes are not stopped by barriers, but are merely reflected. Because of this behavior, areas surrounding the barriers should be monitored regularly for escaped rhizomes that should be cut back.
Regular mowing is another method that can help control bamboo over time. Because bamboo is a grass, it can tolerate occasional mowing, but does not tolerate frequent mowing. Mowing practices, similar to that in a home lawn can eventually deplete the bamboo rhizomes and offer some control. Two to three years of frequent mowing are often needed to see results.
A final, and often necessary, method of control for bamboo is the use of herbicides. A non-selective herbicide with the active ingredient glyphosate is the best option for homeowners. Glyphosate has very little residual soil activity and will only kill plants that receive direct control.
For glyphosate to be effective, the bamboo must be mowed or chopped and allowed to regrow until the new leaves expand. Glyphosate should then be applied to the leaves. Keep in mind that one application of glyphosate will not eradicate the bamboo infestation. It can potentially take two to three years to gain complete control.
While bamboo control is not impossible, it can often seem that way. Staying on top of the problem is one of the most important things to remember.
An intensive control method over several years will be necessary to eradicate a bamboo infestation. One of the best methods of control is prevention. To eliminate all of the hassles of trying to control or eliminate bamboo from your landscape is to not plant it at all.
“Growing Green” is contributed by Lehigh County Extension Office Staff and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-746-1970.