When you say 'last spring' do you mean last year? But if they went in this year I wouldn't cut them down at all ... as you probably know they will flower in July.

However, if they are 'leggy' then maybe give them the Chelsea chop, i.e. just about a third off towards the end of May.

Which Achillea plants are they. There are lots of different ones and they are treated differently, or at least mine are.

Thank you Sheila and Owd, I put them in, in spring 2023, I am not sure what they are, but I will follow your advice. Thank you

Hi Callie, if they are the tall ones, just treat them as any other perennial. Once the new growth is visible at the base, remove all of last year’s dead stems. One of my favourite plants!

Thank you for your help Karen, its one of my favourite also.