I have two tamarisk - one flowers before its leaves, the other after and both are looking very leggy and messy with whole branches lifeless.
Most of the tamarisks round here look pretty much the same.
Anyone found a good way of keeping Tamarisk looking good.?
I’ve seen it in the wild in semi desert places and it’s always looked very leggy and twiggy and a bit sad, I think that’s just how it is. It looks nice enough for 2 seconds when it’s in flower.
Prune hard says Gardener’s World
Can always hedge your bets and cut half down hard this year and other half next.
I see what you did there. 
I’ve been pretty brutal. Left a couple of longer branches. Quite frankly, if it gives up the ghost then so be it. We’ll see what the ruthlessly pruned bits manage to do.
Unfortunately not. I had one in my previous house, and it wound me up so much getting dead twigs in my face every time I walked under it that in the end it got the chop. By then though, it had apparently exhausted itself and wasn’t doing much of anything, even the flowering period was less than spectacular. Perhaps this link might help?