My sister has recommended shearing my phlox, nepeta and coreopsis by half as the leaves and stems appear in spring. This worked well on the tall phlox and nepeta last year, giving them hardy stalks, but I’m not so sure about the coreopsis. Should I wait and shear the stems after the first bloom? Last year I did not shear them at all and the flowers flopped all over the garden.
The coreopsis is in a prominent spot in my front gargen, so I think I’ll wait to shear until after the first blooms pass. Last year, we had a crazy amount of Spring rain that might have contributed to the leggy, flopy appearance.
I cut some of the phlox back alrady, just to see what will happen, and I now wish I had NOT cut back the nepata because it’s lost it’s nice, naturally mounding shape. Hopefully it will fill in!
In the past I have given post-bloom haircuts, but not cut back all the way, to C. verticillata. Nepeta ‘Walkers Low’ has always responded wonderfully to a post-flowering hard cut back, getting rid of the floppy stems and reblooming again to a lesser degree later in the season. I normally cut my Phlox back by about 1/3 by the first week in June. Smaller less robust plants are given a small pinch or left alone. Monster phloxes outgrowing their space get chopped even harder. They love it!