Thank you tcameronk for your input - that is very helpful

Late Sound-
tcameronk is absolutely correct in all the points. My only concern is why you think you need barrier for a clumping bamboo in the first place. If you feel you need barrier, though, you don't need to encircle each plant. Just put in barrier in a large oval that surrounds all of them. If you are just trying to stop a clumper from moving too far in one direction, you can just have a one-sided barrier. However, a clumper is likely to take probably 10 years before it even expands its root mass diameter by more than a foot or two.

I was just worried that bamboo may go wild and take over the entire yard. It is very comforting to now know that it will take 10 years before they will expand root mass more than a couple feet. I will go ahead and order a few Bambusa textilis 'Gracilis' for my yard and plant them without any barrier. Wish me luck and thanks again for your insight about bamboos

Don't worry about a bambusa. I think you heard too many scare stories about running bamboo and generalized them to all bamboo. I have been growing about a dozen different types of clumpers for 10 years and they are all perfectly behaved :-)

Root masses will expand faster if you're in a warm climate. I planted several clumpers (oldhamii) about 6 years ago, and they've more than tripled in root spread.

Yay! I planted them to screen my house from neighbors.

more than tripled in root spread in 6 years..... whew. Now you make me worry again

Late sound-
steiconi is in Zone 12a; I'm in 8a. Where are you?

I am in Houston, TX - zone 9 I think

I would just like to add that most clumping varieties do eventually reach about 4-6' diameter at the base when mature, so keep that in mind. As long as you have enough space for that kind of width, you should be fine.

Our clumping bamboos (mostly Fargesia) have at least doubled in base diameter (some tripled) over the past 2.5 years (three springs in the ground including this year), so they can widen quickly in ideal conditions. We're in Zone 8 in Western Washington.

I have a Fargesia nitida and a Fargesia scabrida that I planted in Western Washington 10 years ago and they are about 2' or less in diameter at the base. Certainly, size characteristics will depend on the species. I have seen clumpers in SE Asia that had bases 10' in diameter, but they were bamboo which could not survive in most parts of the U.S. It is certainly fair to say that clumpers, like any living plant, will get bigger as long as they are alive. However, with a clumper, you do not have to worry about a rhizome traveling 10', 20' or 30' underground and putting up shoots in the neighbor's yard. You know exactly where the roots are, and can always split off a portion if the clumper gets too large for your tastes.