David-

I live in your area (but Eastside) and I have been growing all kinds of bamboo for over 20 years. The hardy, temperate running bamboo are the most common around here, and I have a lot of those. I also have a number of clumping bamboo, but not nearly as many kinds as I have running. You are correct about rufa, I have a beautiful one that's been in the ground for 15 years and it's only 6-7' tall and very bushy. Robusta would be a better choice for a taller hedge, and you should know that it is not "stripy": it simply has persistent culm sheaths that stay on for a while and then fall off or can be stripped off by hand as they get dry and brittle.

In this area, I've never had a rhizome escape from under a barrier that was 2' deep, but I want to know what you are using for root barrier. Is it HDPE bamboo barrier, or what? Also, a 2' diameter barrier is pretty confining. If you instead put in a large oval barrier that was 2' from front to back it would lead to much better growing conditions for the bamboo.

I'm also going to suggest you use more than one kind of bamboo in your hedge. The issue is that bamboo experience "flowering," which is when they set seed. Nobody can predict when it happens and it may occur every 20 years or every 150 years, but when a species starts to do this the plant will almost always die after it flowers. And the problem is that it is not limited to one plant: it occurs globally to all of the plants of that species over a 2-3 year period. I have grown over 100 species of bamboo in the last 20 years and I have had 6 or 7 different species flower on me and die. If you make a hedge out of only one species, you might be unlucky and have the whole thing die. That's why I recommend you build a series of oval trenches and plant two or more different species. Don't mix them, as you would have an impossible time digging out only the dead ones if you ended up having a flowering event. I'm not trying to scare you off, as this may never happen to you. But I thought you should be aware of this interesting phenomenon.

As far as species, I can recommend many. Here are just a few: Ph. nigra (Black bamboo); Ph. nigra 'Boryana' (Snakeskin bamboo); Ph. aureosulcata 'Aureocaulis'; Ph. aureosulcata "Spectabilis'; Ph. nigra henonsis (Henon); Ps. japonica (Arrow bamboo); Q. tumidissinoda (Walking stick bamboo); Ph. viridis 'Robert Young'; Ph. viridis (Hedge bamboo). These are all running and they stay green all year round. Besides fargesias (all are clumpers), I am also partial to Chusqueas (a clumping South American bamboo), but these have been flowering lately. There are many other bamboo that do well in our area, so here is my suggestion: take a trip to Boxhill Farm nursery in Duvall. It's a little bit of a drive, but they have the largest and best priced selection of bamboo anywhere in our area, and it will give you a chance to look at bamboo in person and select plants that are appealing to you.

Fargesia. Fargesia is a clumping bamboo genus native to China's mountains. Our varieties are well-suited to the Seattle climate, remaining green throughout the winter and tolerant of drought.