I bought several 'Ascot Rainbow' plants last year and they were beautiful. This spring I cut them back as I did all my other euphorbias but they are not leaping back to life like the others. Aren't they supposed to be cut back? They are pretty much just sitting there looking embarrassed that I scalped them. Yikes.
Euphorbia 'Ascot Rainbow'
They can be cut back - best cut back by a third. They will probably recover after awhile.
I've raised Ascot Rainbow for years...and it does resent being trimmed in the spring. We cut our landscape plants back by 30% in the fall and it gives the plant plenty of time to grow over the winter and bloom beautifully in the spring...