I live in temperate, rainy Washington State and we have a bamboo containment issue. Here is the deal: Black cane bamboo (running) was planted in the corner of our yard as a screen. The corner abuts against a sidewalk and our six foot wood fence (see picture). The installer dug a rectangular trench on three sides of the bamboo bed but neglected to dig a trench along the sidewalk. I assume that they thought that the sidewalk would be a barrier (its four feet wide). The three-sided trench was filled in with a four inch thick concrete wall approximately two feet deep. Again, along the sidewalk/fence there is no barrier. The bamboo was planted almost ten years ago and during the last three years it has sent corms under the sidewalk and into the parking strip. It is really starting to reach almost twenty feet away down the parking strip towards the front yard. I keep digging it out as best as I can, but I'm a little worried.

What can you suggest to tame this beautiful and aggressive plant? I was thinking of taking the fence down temporarily, digging a trench (with what?) two feet deep and the length of the sidewalk, laying in a plastic barrier (how thick?), and somehow attaching the plastic to the concrete ends (again, how?). My idea is to cut off the runners from the mother plant and then dig up any new bamboo that comes up next spring (how long can a rhizome survive without photosynthesis?) All advice is welcome as I want to get this under control this fall. Thank you!
Bambooza

The answer to two of your questions are at least 30", 60 mil barrier.

How wide is the screen? How long? How much space is there between the screen and the house (inside of the lot)? Could you pull out the concrete and put undulating barrier around just three sides? Can you start adding dirt to turn the bamboo into a raised bed or bamboo hill?

You can get rid of disconnected (or connected, for that matter) rhizomes by putting some roundup in a cut culm on the end, no problem.

Have you considered thinning/pruning/or hedging the screen to reduce vigor?

The problem right now is the existing 3-sided barrier. If the installer was thinking, he would have put the open side facing the yard, so you could have rhizome pruned that side since there is easy access. You can't add the plastic barrier to just the 4th side, as there's no good way that I can think of to connect it to the concrete, and rhizomes will escape. Since I don't know how wide the planting is or how much access there is on the fence side this may not work, but I would dig a trench on the fence side, sever existing rhizomes, cut any shoots that come up from the escaped and now-severed rhizomes (over and over and over until those rhizomes have depleted their energy reserves and die), then fill the trench with something softer than soil like mulch or sand. Then every year you'd have to ensure that you clip any new rhizomes that have made it into the trench. It's probably also possible to fill that 4th side with concrete as long as you can ensure a solid and long-lasting fit against the existing concrete. I don't know that you can though.

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Alan.
My blog: It's not work, it's gardening!

Isn't the mowing of the tree lawn keeping the bamboo from coming up there? If it is mowed regularly I'm not seeing what the issue is?

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Brad Salmon, zone 5b/6 Southern Indiana
Winters -20 to -25C. Summers 30 to 35C , humid. 115 cm annual precipitation, frost free from May through early October. 259.3 meters elevation. Growing 150+ species. http://www.needmorebamboo.com/

Bamboo begs to be cut to reduce leaf mass which feeds it's growth. Once a stand reaches the desired size it's necessary to remove an equal amount of older culms as shot the previous Spring, to maintain it's size. In this way an equalibrium is maintain and vigor is controlled and the bamboo is less inclined to run and adopts a clumping habit which is more desirable to my eye. Depending on the size of the grove, rhizome pruning with a shovel is enough to maintain a boundary. For larger groves like a hedge, I trench a shovel's depth and width which exposes the rhizomes when they cross and I cut them as necessary.

Thank you for the thoughts and suggestions all. The bed measures 3 feet by twelve feet (the long side is along the fence in the picture). I like the idea of a more permanent solution because we may rent this house and I may not have the time to prune a trench of new rhizomes. I get that it would be hard to connect a plastic barrier or new cement for that matter with the existing concrete. What if I dug a trench along the fence and around the current bed (full circle) and inserted a plastic barrier(30inches deep with 60 mil plastic) around the whole bed? The worst access is along the fence side but I could but some of the canes there and maybe not have to take down the fence. What is the procedure for laying plastic? How much overlay do you need for the ends? Also, how many years will the cut off bamboo continue to try and grow? I try to stay away from herbicide, any other solutions besides digging and cutting? Thanks!

Respectively,

Bambooza

Here's a way I'm able to keep my yellow groove from taking up more space than I want it to. I simply used a shovel and dug in a circle around the grove, and the shovel which can get down 8-10 inches goes well deeper than the rhizomes grow, at least so far. I could turn these into new divisions if I wanted to, but yellow groove is so common around here so I'm not too concerned about them. I'm also going to spread a layer of mulch before fall to cover them up completely.

I'm not sure if aerial rhizomes store energy, maybe, but I'll probably cut them all off right after new shoots leaf out. This is a pretty thick grove so the rhizomes grow pretty far, but digging around the grove annually seems to be enough to tame it.


In your situation, you may need to dig a trench and give the bamboo a couple feet of space between the fence and edge of the grove. Barriers work however the rhizomes will continue to try and find ways to escape, and may eventually puncture the barrier. I think if you go with the barrier, I would suggest having the barrier at least 1-2ft away from the fence so that you can catch escaping rhizomes much easier.

Here's my other form of control, however this also gives me some easy potted divisions which become well established plants once they generate true shoots in the pot.

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