Timber bamboo can refer to a number of very different kinds of bamboo.

You need to know exactly which kind of bamboo you are planning on planting.

Giant Timber(B. oldhamii) is a large clumper. You won't need a barrier for this one.
Giant Japanese Timber(P. bambusoides) is a large runner. You WILL need a barrier for this one.

How tall of a bamboo are you looking for?

Do you want it for a screen, or just an asthetic or ornamental plant?

Kt

The type of Timber Bamboo I want to plant is Phyllostachys bambusoides. It is supposed to get really tall, which I like, but I wonder if the culms would fly around when it gets windy. I wouldn't want them blowing against the house or anything like that. I want to plant them around the permiter of my back yard, for screening/aesthetic purposes.

Here is a link that might be useful: timber bamboo

It won't be much of a problem unless it rubs against the roof or other part of the house where it might rub off some paint, but that wouldn't likely happen unless it gets very tall. You could keep the culms that grow close to the house cut shorter.

Also, it will not likely hurt it if it bends over or should happen to break and fall on your roof either. The culms are relatively light.

I would be more concerned with containing it. A barrier can fail especially if it is installed incorrectly. I'm not sure how cold it gets in your area, but you might want to plant a clumping bamboo. It would cost more for the bamboo, or either it would take more time, if you divide it yourself over the years, to encircle the entire area, but it would be barrier-free, saving a lot of trouble later on if the barrier failed and left you having to dig out the runaway boo...just a thought.

Some people do rhizome trimming as an alternative to installing a barrier, but it also takes a little work, and may not be aesthetically acceptable in your yard.

Clumpers will give you a thicker/denser screen also. Most clumpers that will grow here will only reach a height of about 40 feet but most are shorter. P. bambusoides can reach 55 feet here, which is about twice as high as most telephone poles.

Kt

Are there any clumpers that have thick green culms?

There are clumpers with thick, green culms...but they will not survive winter in Zone 8.

What about something like Borinda papyrifera or Borinda boliana? I don't know who would have them, but the papyrifera is on my short list of bamboo I want to have.

In your particular area, you might look into Bambusa textilis. Here in zone 8b it survives Winters down to as low as 15F with only some leaf burn. The dry north winds are harder on it than the cold.

It grows to 40 feet in height and has culms just over 2 inches thick. The larger culmed clumpers are less cold hardy, such as B. oldhamii(4+ inch diameter culms here), which will survive temps down to 15F for short periods at a time.

I have a couple of dozen medium to large clumpers here and the bambusas do the best. Most do very well except for leaf burn during winter, but they quickly recover.

If you are located in a protected area, where the temps are warmer than the norm for your zone, I would try a few clumpers and see how well they do...you may be surprised.

Good Luck

Kt

What about Bambusa clone X? I heard that one was cold hardy.

Clone X is quite cold hardy, and gets culms about 2.5 inches in diameter, I'm told.

It gets very tall, up to 70 feet, but it also leans outward quite a bit, so it might not be a good screen for a small backyard.

Kt