Floppy achillea

berarde

I have had moonshine which has been self supporting not needed staking. I Put in some Cerise last year in a spot perhaps less sheltered. It is about 3 feet but the whole group is flopped forward. I've put in some supports for next year, but wonder if I can do some spring pruning to make more compact plant? Maybe otherwise look for a more compact variety, say 1 and a half to 2 feet?

Obelixx

My plants in full sun stand up.  The ones in partial shade flop towards the sun.  I suspect a Chelsea chop in late May would help.