Ordinary sambucus nigra, elder, the green form?. Easy, when the leaves fall off, cut it hard back to the old wood. You'll provoke it into vigorous new growth next year, and it'll forgo flowering for growing instead. You'll get flower the following year. Otherwise, a late summer trim back, removing the longest offending stems won't harm it. It's as tough as old boots

I was advised by David to cut my Sambaccus Nigra back by a third plus any dead branches, I did this and it was fine, I do it every year now in the autumn, this year i cut it in spring before the leaves formed, I hope this helps it is a beautiful shrub isn't it? David made pink champagne and Elderflower cordial from his flowers and berries!

I could tell you but the rest of the RHS gang know best.

Pinch the tips out..... Stops it getting leggy.

I cut mine down to 18" tall each winter.

Thanks everyone