There are many types of bamboo but in general they can be divided into either clumpers or runners. The clumpers are non-invasive. The vast majority of clumpers are sub-tropical or tropical, althought there are a few that are extremely cold hardy, most of those can’t handle the heat in the southeast. Because of this, all I grow and sell are the running types of bamboo. These bamboos spread by sending out underground rhizomes (these are rootlike, underground stems). All these bamboos are cold hardy meaning they will stay green and leafy down to about zero. A few are hardy down to -15 or even -20 degrees. Most bamboos in this country are runners. The clumpers are usually in places like south Florida, along the gulf coast, parts of Texas, and Southern California .
Most all the running bamboos have one thing in common, they spread by sending out rhizomesunderground and these must be killed or diverted. The same bamboo that may be well behaved in a cold climate can be very invasive in a warm climate with plenty of water. Running bamboos spread by sending out underground rhizomes which then send up new shoots around the original planting. A large grove of bamboo may be a single plant, interconnected undeground by rhizomes. If you have new shoots coming up in your yard, a few inches to several feet away from other canes, you probablyhave a running bamboo. Most of these runners will more or less double in size each year so they can quickly get out of control
There are several ways to control running bamboo. One of the simplest is to kick over or cut off unwanted shoots each spring. This might be more difficult than it seems as there can be great numbers of new shoots each spring, perhaps hundreds. If you can place the bamboo in an open area that you always mow around, you can control it. If you stop mowing for one season, you will be amazed at the number of new shoots.You must mow every year. In order to kill a grove of bamboo you must cut down all the canes and remove any new shoots. You may need to do this for 2 to 3 years. Eventually the bamboo will use up all it’s reserves and die. Remember, they are connected underground so removing the canes and new shoots in one area is only a temporary solution. They will be back if there are canes remaining to supply nutients to the area where you have removed bamboo. If you manage to kill the bamboo grove, you must watch for the next few years and cut down any new growth you might see. A very small cane and piece of rhizome can start another huge grove of bamboo.
A popular method for controlling bamboo is to install a rhizome barrier. Usually this is a thick plastic (30 to 60 mil), 24 to 36 inches in width. Basically you dig a trench around the bamboo, install the barrier making sure the seams where it meets are well sealed,then backfill. It is necessary to leave the barrier sticking up a couple inches above ground as the rhizomes can go over it and continue to spread. You will need to check the barrier from time to time and remove any rhizomes trying to go over. In a cold climate with dense, clay soil 24″ deep may be fine. In a warm climate with sandy soil you should definitely go 36″ deep. It’s best if the barrier canl be slanted outward at the top to guide rhizomes upward instead of allowing them go down and under the barrier. We sell rhizome barrier in 30 and 40 mil thicknesses, 24″ wide. We can supply 36″ material on special order.Take a look here for information on purchasing and installing. While rhizome barrier can be an effective method of control there are many variables that should be taken into account. Rhizome barrier should be used in conjunction with other control methods for best results.
Another method is to dig a trench around the bamboo and leave it open.This probably doesn’t need to be over about 18 inches in depth as there is no barrier forcing the rhizomes to go deeper. Even the rhizomes of giant running bamboos spead our only a few inches below the surface. By inspecting the trench regularly you should be able to spot the rhizomes going across the trench and cut or break them. Just as these bamboos send up large new canes each spring, they send out large new rhizomes in the fall. In a variation of this method the ditch is filled with gravel or mulch. Each fall a shovel is thrust down into the trench, going all around the grove, pruning any rhizomes that are crossing the ditch. I am aware of a few people using this method quite effectively but it means always being vigilant if you want to control the spread of a running bamboo.
At my nursery I use a combination of methods.Some groves are in large open areas and I simply keep the surrounding area mowed for 20 to 30 feet out from the grove. We have a pond and streams and I’ve used these as effective barriers as bamboo generally won’t cross water or a wet area. (contrary to popular opinion, most bamboos won’t grow in wet or “swampy” areas”.) I have a long, concrete driveway over extremely compacted soil and this has also proven to be an effective barrier. Even a dirt road that is well traveled will often form a barrier. I have a large grove of Moso surrounded by a tractor trail/dirt road. If trucks or equiment is being driven over the road when new rhizomes are growing they are usually killed at that point. Skipping a seaon of rhizome growth will mean more work in the future and less likelyhood that you will keep the bamboo under control. I’ve seen a small island in a local lake that had been planted with bamboo. It was still young when I last saw it but I’ve thought about it, seemed like the perfect solution to controlling bamboo.
I am often asked about using some type of herbicide on bamboo. The herbicide would have to be applied to new growth each year for a few years to kill the grove. I’ve seen bamboo groves that have been sprayed and for the most part it only seems to stunt it’s growth. As soon as the spraying stops the bamboo starts to recover. This also means lot of chemicals being in the ground, in the gutters and into the waterways. For these reasons I do not recommend using herbicides to control bamboo.
My own experience controlling bamboo.
I’ve had three fairly well established groves of bamboo that needed removing or transplanting. The first was a grove of Robert Young that had grown and spread tremendously – and was planted near my roof. There were some nice canes, 2 and 3 inches in diameter. We dug these up with the help of a fellow bamboo lover and transplaned them to his place, basically a full grove. I think most all survived.
The second was a grove of P.b. Slender Crookstem. I planted this bamboo in a choice location in the early 90’s. It grew faster than any other species I had and soon outgrew the location and appeared to be heading for my Moso grove. I decided to eliminate it while I still could. It covered an area about 40 by 60 feet, along a creek. I first went in with a tractor and dug up as many of the rhizomes as I could. The soil is very sandy but it was difficult to remove much of the bamboo. I then cut all canes to the ground. Over the summer I cut any new shoots or growth that came up. I continued to remove all growth over the next couple of years. At this point the bamboo has been cut back for 5 years and I still find a few new shoots along the creek. However, I am confindent that the bamboo has about given up. I’ll watch carefully this summer and maybe I will finally eliminate this bamboo.
The last was a very small planting of S.okuboi. It was near my flower beds and quickly invaded. It loved the fertile soil in the beds and soon began to pop up all over. My wife and I cut and dug up all the rhizomes two years ago. Last year we had quite a few shoots come up but again we cut and dug all we could. This year only a few small shoots came up and we’ve removed everything we could find. It appears to be about dead now but I will have to watch carefully. All it takes is one small shoot to start the whole process over again!
Example of an Effective Control Method
This grove of Gray Henon is locted in an urban part of Birmingham, Al. The grove is 0ver 300 feet long and only about 6 to 8 feet wide. It is planted in a narrow right of way between a city street and a long, gravel driveway. The compacted soil of the driveway prevents the rhizomes from crossing over into the yard. The owner of the home says the bamboo was planted about 12 years ago and has never crossed his gravel driveway. He mows along strip of grass between the bamboo and his drive. As you look down the long driveway there is another home at the end and the narrow right of way opens up to an undeveloped patch of land. THe bamboo has now reached this area. I’ll have to come back in a couple of years to see how it’s expanded.