1) Do you know how to identify age of bamboo?
2) Can you identify bamboos?
If you can get 4 years old bamboo's branch during fall, cut off branchs from colum, wet branch and cover with tarp, leave it for 10 days or so. Doing so, leave fall off easely from branch.
yeloow grove bamboo, and black bamboo make "soft broom" Moso bamboo's broom is stiff broom.
18 gage cooper wire or black tie wire for rebar are easy to work with.
3/8 inch or so above node, make 1/4 inch or so small hole and use "mekugi" which is short bamboo branch serve as holding wire /easy to tire and sturdy.
You need 50 plus minus bamboo barnchs,
Long ,stiff barch 6 to10 banchs for middle, soft and shorter one are placed around it.
Hachiku or maake works best. Yellow grove bamboo's colum is thin and weak.
If you are 6feet or taller, make handle 6" or so longer. Japanese standard bamboo broom are made for 5 footers.