When I have grown nepeta, {which I don,t now because cats love to roll in it, and I don,t like cats in my garden}, I have always cut it back when it startyed to look untidy, and it always came back the following year, so if you want to cut it, go for it, Derek.

I cut mine back last month as it was so big and already its a nice plant again.

Grew this for the first time last year - I cut it right back once flowering was over. Grew back again and looked great with a few later flowers. I have done so again this year but not because it had finished flowering but because it got a bit wet and was looking on it's last legs. Now making new growth, so I would say go for it!

Thankyou everyone. Done and dusted, and looks so much better. Had better do somethings in the house now, urhgg.

I cut mine back quite a few weeks ago Mary, and they've flowered again, theyre ready for another prune now!

Mine is huge and flowering again