Have quite a lot of bamboo growing in a small garden and a lot of it is
rather out of control. I thought I would try ammonium sulphamate to try to
kill some of it. Is that the best thing? Also is it an idea to trim it
down short to within a few leaves nearest the ground?

The reasoning being that this ammonium sulphamate is 'systemic' and this way
it would have to travel less distance to get to the roots? Thanks for any
advice.