Wait until the flower petals have faded, dried, or started to drop
Follow the stem down to the first set of healthy leaves or a side bud
Use clean, sharp pruners or scissors
Cut the spent flower stem just above a leaf node or side shoot
Remove the entire flower head and stem if no new buds are present
Deadhead regularly during the blooming season to encourage more flowers
Remove any damaged, brown, or diseased stems at the same time
Collect and discard the cut flower heads if you do not want self-seeding
Stop deadheading in late season if you want seed heads for birds or winter interest