When Should I Prune Achillea

The National Gardening Association recommends cutting back yarrow plants to within 1 to 2 inches above the soil line after the first killing frost in autumn. Cutting back yarrow plants in autumn will eliminate places where pests can overwinter and will also provide room for new green growth to emerge in spring.

When can I prune Achillea?

Deadhead spent blooms to prolong flowering and either cut back blooms in autumn or leave the seedbeds in situ for the birds. Lift and divide congested clumps every three years, in autumn or spring.

Should I deadhead Achillea?

Ideally, to prolong flowering, Achillea should be dead headed, but it is tempting to leave the flowers on the plant, because they look so good as they fade. … They will return and flower well each year although a shorter lived perennial.