How to prune Albizia julibrissin?
I have 3 seed-grown Mimosa's, which I would like to keep in the shrub size-range. The largest of them has a 2' 'trunk' and two wings, almost 6' long, one opposite the other.
How do I rein this guy in? He's in his second year from seed, and growing in a 5 gallon pot, banked into woodchips.