How to transplant from a main bamboo plant?
Answers:
I'd imagine bamboo isn't different from any other grass-like plant in this regard. They're not very finicky but it would be best to do when they are dormant (if you're in an area where they go dormant) or not growing rapidly & when it's not overly hot. Just use a tile shovel to cut down through the roots to separate a bunch from the main clump. Do this all around the separated clump & get as deep as you can handle- say about 10" deep. Drop it in a hole that's a little bigger 'round & about the same depth as the ball you've dug. Lightly firm fill dirt around it to the same (or slightly greater depth) as the original depth. Water regularly till well established. LOL
Other answers:
Chop out a runner with a spade and transplant it, you can't kill bamboo.
Chop out a runner with a spade and transplant it, you can't kill bamboo.
cut a whole bamboo pole with a lot of side branches .
then with a chain saw (if possible ,because it cuts clean)
cut the pole into segments .
each with a branch .
then plant these pieces deep in the ground ,over a meter ,
with the branch sticking out of the ground.
keep it very wet .until you see that it has taken.
from one pole you should get 20 or 30 plants
i have done this many times