They should be fine. As long as the soil is moist there is no problem. Bamboo are tolerant of over-watering as long as they aren't sitting in standing water. The main issue will be that in several years they may need to be divided, and typically it is nearly impossible to un-pot them after that long in a half barrel. The problem is that the rhizomes will fill up the space and grow out to the sides and exert considerable pressure. That pressure coupled with the fact that the inside of the barrel is slightly rough means that it won't want to come out. And the density of rhizomes and their toughness will prevent you from easily cutting the root ball into big chunks that can be pulled out without mangling the plant. The last time I helped my neighbor with this situation we needed to destroy the half barrel by knocking the steel rings off with a hammer and punch and then peeling off the staves so we could get access to the bamboo and divide it.

Thanks for the reply. I haven't watered them for a 3 days and only the top 1/8" of soil is dry so i think the watering lines will keep the soil nice and moist. I think i have enough drainage so that the roots are in standing water. In the Dulcis i drilled about 10 1" holes and in the Vitatta i drilled 7 3/4" holes. Should I drill more holes?
I don't mind having to divide them down the road, I've got a few spots in my yard that I'd like to add more bamboo screening. Plus it's a great excuse to visit the winery and buy some half barrels :-)

I think you're good with the drainage holes. Feel free to experiment with watering frequency. You'll know that it's definitely time to water if you see the leaves roll up longitudinally (it's a moisture conservation move).

What about the tips of the leaves? Could that be from the drive home? It was in the back of my truck uncovered, i didn't go over 45 MPH on the local roads home. It was a 20 minute drive. The Vitatta seems fine, Here is a close up of the Dulcis leaves.

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