There actually aren't that many bamboo that look like Alphonse Karr, and your photos look just like my A. Karr. I agree that the stub of an old culm is a little large in diameter for A. Karr, but I'm still putting my money on that. Take a look at the pictures in the link below, and compare it to what you have.

The second one is harder because young plants are harder to identify, because it looks like a lot of other green bamboos, and the photos don't give a lot of detail. If you have a picture of an emerging culm, it might help. Also consider posting on bambooweb.info where there are more bamboo experts.

Here is a link that might be useful: A. Karr pix

Maybe this picture shows the striping on the Karr (?) a little better.

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Thanks kudzu. And when I get a minute I'll run out and snap a picture of that shoot. In the meantime I'm looking at the link you posted and I'm happy with what I'm seeing.

aloyzius-
That is a better picture. After seeing it, the other suggestion I have is to look closely at how the green stripes end up at the nodes. Bambusa vulgaris 'Vittata' -- also known as "Painted bamboo" -- has distinctive green striping that looks like it was painted on. Take a look at some of the closeups of the culms in the link below and tell me what you think. Vittata also has large diameter culms when it is mature.

Here is a link that might be useful: Vittata

I see what you mean. And mine is pretty different, I think we can rule that out. Here's a blurry shot of the node.

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aloyzius-
Just heard from a friend of mine whose opinion I respect in these things and here is what he had to say after looking at your photos:

"I'm pretty sure that the yellow one is as you mentioned B. vulgaris 'Vittata' and I also think his second bamboo is Bambusa ventricosa. I became pretty familiar with both of these species in Hawai'i."

That is so cool. Thank you so much.

I did some reading on those varieties, and poked around the botanical gardens, and those things are huge. Definitely not the listed hedge bamboo size. I guess I better move them further from the fence, and purchase a sawzall.

As an update, a month later, it looks like kudzu and his buddy are right on. The ventricosa has sent up one shoot and now it is all zig zaggy which is exactly what one would expect to see. It is a drag they will both require significantly more space than they were given. The vitata has not sent up any shoots but the more research I do, the more convinced I am. I will dig them up in the winter when the timing is better.