Bamboo containment
Containing bamboo is a matter of diligence. The excellent article below first appeared in the Southeast Chapter American Bamboo Society Newsletter (Volume 8 Number 1). Reprinted with permission of the author.
Controlling Bamboo
There are two main methods used to contain running bamboos. You can either install a physical barrier or use cultural methods to keep it in bounds.
A physical barrier has the advantage of being permanent (if well designed) and needing minimal effort afterwards to keep the bamboo within. Its drawbacks are the expense of the barrier material, and the labor needed to dig a trench and install the barrier. Barriers may be made of fiberglass sheets, sheet metal, and various other composite materials. It needs to go at least 2' deep and be slanted with the top away from the bamboo side of the barrier. This forces any rhizomes up to the surface where you can see and cut them as they try to get over the top of the barrier. Bamboos tend to be deeper rooted in lighter soils, so if you're on light sandy soil, go down 3' ; if you're on heavy rocky clay, you might get away with 1' to 1.5'. The top of the barrier needs to be 2"- 3" above the soil line so it doesn't get buried by subsequent year's accumulations of leaves and soil and any mulch you might add. Joints in the barrier material need to be securely fastened to prevent the bamboo rhizomes from worming their way through any cracks that might be at the joints. Once installed, all you'll need to do is walk along the barrier once or twice toward the end of summer to spot and cut any rhizomes that are trying to jump over the top of the barrier and, also to make sure all of the barrier top is still exposed above the soil line. The saturated soil along a stream or swamp can serve as a natural barrier that will contain most bamboos, except for possibly Phyllostachys purpurata , which is said to be able to grow into shallow water.
There are various cultural methods of controlling bamboo. Cultural methods are cheap but require some of your labor at a specific time of the year to control the bamboo. If you skip a year when using these methods, then you have a lot of work ahead of you to get caught back up with the bamboo. One cultural method is simply each spring to cut any shoots coming up outside the area you designate as "bamboo grove". You can either cook up and eat the cut shoots or throw them into the bamboo grove to compost. If your bamboo is surrounded by lawn, then just mow frequently over the area where the bamboo is coming up during the spring shooting season. This is how the moso grove at the Old Silverbrook Cemetery has been controlled for the past 70-odd years. It is contained on two sides by a stream and swamp, on the third side by mowing a strip about 80’ wide and on the fourth side there is a one lane asphalt road which it hasn’t yet been able to burrow under.
An alternative cultural method is cut in late summer a 1' deep line along the edge of your bamboo grove with a shovel (or cut 2’ deep with a ditching machine, if you have one). The best shovel for this is one of those long handled, flat, straight edged transplanting shovels. What you are doing is cutting any bamboo rhizomes that have spread beyond the grove during the summer and these young rhizomes aren't capable yet of surviving on their own. The first year you do this on the edge of an established grove is going to be tough digging since you are having to cut through the old hardened rhizome mat, but once the line is established, subsequent year's cuts are much easier, since the current year's rhizomes are soft and easily cut. Once established, its just a matter of going through and "chop-chop-chop-chop" down along the line with your shovel in late September of each year. When using this method, every now and then a deep running rhizome will escape your cuts and will send up shoots outside the grove. When this happens, cut out the shoots and dig back along the rhizome and remove it. A variation of this method is to dig and maintain a narrow trench 2' deep around your grove and then simply to cut any rhizomes you see trying the "bridge the gap" across the trench. Running bamboos spend the first part of the summer (through June) growing new culms, and remainder of the summer extending their rhizomes. So any rhizomes you cut in October are only a few months old.
If your bamboo has already escaped and you are trying to get it back in bounds again, the first thing to do is to cut off the part of the bamboo that's gotten where you don't want it from the part you wish to keep. You can use either a ditch digging machine or the shovel described previously to cut a line between these two parts. If it's an old established grove, cutting this line can be a tedious job.
Once you've severed off the part of the bamboo grove you don't want, then there are several ways to get rid of the unwanted portion depending on how large an area it covers, what other plants it's growing amongst, and how well established and dense the unwanted bamboo is. Various methods to get rid of it include. 1) Persistently cutting back the top growth until it finally weakens and dies (this will take a couple of months). 2) Cut it back and use a contact herbicide on the new growth coming up (bamboo is fairly resistant to a lot of herbicides so it may take several applications to kill it out completely). 3) Cut it back and lay black plastic over the area to shade out any new growth coming up (if you do this doing the summer in a sunny spot you're also heat sterilizing to kill any nematodes and weed seedlings that sprout in the upper layer of topsoil). 4) If there only a small amount of escaped bamboo, then just follow and dig up the escaped rhizomes (kind of like following and digging up an underground cable), although if there are a lot of roots in the area this method can become difficult. 5) Cut it back and pen a goat or hog over the area. After a month or two you'll have no bamboo and a fat animal. 6) Cut it back and then rototill or deep plow the area. Then go through with a rake and pick out all of the pieces of rhizome in the turned over soil. Repeat the plowing and picking steps several times to be sure you have gotten all of the pieces out of the ground.