It's not too late to transplant, although you will set them back if they get dug up. I also don't understand what the issue is because shade trees should not interfere that much with bamboo growth. I used to have a grove of Yellow Groove that did fine under shade trees. However, it is true that they got bigger after I limbed the trees up. Are you suggesting, though, that you didn't get any growth this year and you think it's because of the trees?

Actually, the trees leaved out in early April this year, usually it would be mid to late April. Therefore, the yellow grove only grew to about 6-7ft tall. They have a good color and are thick, but the height was stunted.

I like the look of the thick caned bamboo, and under the heavy shade (all day) of Oaks and Black Walnut, they looked somewhat dwarfed.

yardman-
There could be other reasons the culms didn't grow as high this year, like water. I've been growing bamboo for years and, although new bamboo culms typically get a little bigger each year, sometimes they put out new culms of smaller diameter and height. You might want to give them one more growing season before digging them up. Or, you could choose to transplant part of it and leave some behind as an experiment.