Rick DeBay wrote in message
I googled for "bamboo root depth" and found a report on a bamboo rat who nests
in bamboo. The report listed the depth of the fibrous root as 130cm, which is
four and a quarter feet. The bamboo type is Sinarundinaria (Fargesia) nitida.
I know fountain bamboo is smaller than lako, but I don't know if you can draw
any comparisons for root depth.
We do have high humidity here in Palm Beach county, but our occasional droughts
can get pretty bad, since we depend on wet season for all our rain.

Clumping bamboos will build UP rhizome. This is almost all above the
surface. I have come across a Bambusa Beechyana here in So Cal with
rhizome that was about 4 feet deep, 1 below surface 3 above. This
beechy is probably well over 50 years old and in horrible neglect.

You may notice if you look at some of the older larger clumping
bamboos there is a mound in the middle. Some of that is leaf litter,
most of it is rhizome.

Chris