nucci60- If you do this regularly, say, mid-summer and again in early fall, you should be fine. Arrow does grow a dense web of tough rhizomes, so don't get lazy and let it go some years. As for spading, that will work with a sharpened one if the ground is not too hard and rocky. I often simply use a long-handled set of pruners as the runners aren't very deep. I uncover the rhizome, open the pruners, put them in place, step down to push the jaws completely down around the root, and cut. Then I grab the cut end and pull out the rhizome. If the rhizome is hard to get out, just slip the sharp end of a pickax under the severed rhizome and pop it out using leverage on the handle.

That's an interesting and complex plan. It will be somewhat effective, but not foolproof. I don't believe it's possible to "fool" rhizomes to prevent them from growing in one particular direction. I also have seen HPDE pond liner that was breached in multiple locations by rhizomes. I have rarely seen rhizomes go deeper than 12", though, so one thought I have to improve your design is to use real bamboo barrier instead of HPDE, and to install it at the backside of your raised bed so that the top side is leaning substantially back from the bamboo. That way, when the rhizomes start moving out and hit the barrier, they should slide up the barrier and pop out of the ground where you can see them and snip them off. In your Zone, clumpers may take a long time to size up and you would need quite a few for a 50' fence line, so runners are probably your best choice. If you go with runners, you'll want the hardiest ones you can get. One of the best ones for that purpose is Ph. nuda, which is hardy to about -20F. If you go to the link I have provided below, you can do a search on bamboo using various criteria to help you narrow down your list. One last thing: when growing a bamboo hedge, it is always wise to plant at least two species. You never know when bamboo might flower and die, and it's always best to have only part of your hedge fail. It might not happen in your lifetime...but you never know. You could also consider a combination of hardy runners and hardy clumpers, as some of the Fargesia species can also handle temps down to -20F. Good luck. Here is a link that might be useful: BambooWeb-Species

Greenguy - it's a baby June, growing in pretty much all day sun, unless it sported into something else? ....and I am sure he got the one to the left...his 3 year old brother was hunting with him, working as spotter. Together, they make quite a team...I don't think the slugs stand a chance. (-: Woodtrush - yes, whoever wrote those lines sure knew what they were talking about, lol

Hi Dotty I have one dwarf bamboo in the ground that I let wander through a persicaria with red blooms. I control it by rhizome pruning. I usually prune whenever I get around to it, be it spring or fall or if I see new growth popping up, I deal with it then. I haven't noticed that it spreads any faster if I do it in the spring. The BEST time is about the end of October so you won't be surprised by new growth in the spring in places where it is not wanted :-D. Different dwarf bamboos are more rambunctious than others, yours may be one of them. If you have lean rocky soil that doesn't hold water it will run but I doubt you will end up with a nice looking plant. Bamboo likes good rich soil like you would grow vegetables in. Regarding rhizome pruning, the main thing is to actually DO it. If you want to keep it in a container and it is really root bound, you could divide it. Take an old saw and simply cut it in quarters or thirds and repot it in new soil. Have you ever cut it back in the spring? This will promote new growth and your plant will look new and fresh again. It is a grass after all. Another point to remember is that in the winter, the abundant foliage doesn't allow adequate rain water to reach the soil so although we had a wet winter your plant could actually be drought stressed. That in addition to being rootbound in a container during the cold will severely stress the plant! I'll check back if you have other questions, good luck.