What is this plant?

[N0tfinished]

Sorry, not a good gardener. I have a large garden that was in the house when I bought it. Although I love it, it overwhelms me! I usually pay someone to prune & clean up a couple of times a year. Unfortunately don't have time or inclination to do it myself (child with SEN)

Anyway a new plant has started springing up rampantly all over one corner of the garden. It's not the usual weeds (thistles, nettles etc)

Can anyone help me identify it? It's clustered around a tree thing, could the unusually hot weather have caused the tree to sprout? I've sprayed roundup and it's working but there are more plants sprouting overnight it seems.

Close up of the tree thing

My guess is Rhus (Stag’s Horn Sumach), and willow of some sort

Looks like rhus typhenia (or stags horn - are the new branches furry?) - i have one as i like the exotic look of the leaves but they do thow up suckers all the time around so i just cut them off where i dont want it. Will have bright red pointy things in autumn and the leaves go orange and red as well.

The branches are furry, that must be it. I'll have it cut out then, I was a little confused by how vigorous it was. Thanks a million

Stags horn throws out suckers and the more you chop it, the more it will throw out, just to warn you. The tree behind looks like a willow. Is there a stags horn somewhere else in the garden?

Ok I'll keep spraying when the rain stops!

I don't think I have any more but my neighbors garden does. I'll keep on top of it, thanks a million