If you can wait until the bamboo is more dormant (after September), it would be better. However, I have been known to ignore this advice, dig bamboo this time of year, and have it survive. New shoots may well die, and you may have some of the bamboo divisions fail as well. So make sure you: 1) dig as big of rootballs as you can, 2) dig more than you need in case you have some divisions that are goners, 3) douse the rootballs with water before you transport, 4) protect the foliage from the wind as you drive, and 5) have your transplant holes ready so the rootballs can get back in the ground ASAP. If you've never dug bamboo, email me and I'll send you instructions that will make this project easier.