When Should Sunflower Heads Be Cut?

Deadheading sunflower heads is a crucial process that ensures the seeds inside are fully developed. The best time to deadhead sunflowers is when the petals have withered and fallen off, and the back of the flower head has turned brown. This usually occurs in late summer or early fall. Some signs to look out for when deciding to deadhead a sunflower include the bloom having faded and looks spent, the head of the sunflower sagging over heavily, and the head being plump and somewhat loose.

To deadhead sunflowers, start by cutting them back twice a year, cutting them down to half their size in late spring or early summer and then reducing their size again by a third. Once the sunflowers have died back completely and the backs of the blooms are brown, it’s time to harvest. Cut the stalk with sharp scissors or pruners about one foot down from the flower head and place it in a container that can catch any loose seeds.

After the flowers have fallen off, leave the flower head on the stem for at least two weeks. Once the petals have faded, cut the flower heads off and store them in a sunny, warm, dry place. Leave them in the ground over winter. In early spring, before bees are out, cut the stalks for use in the garden.

Ideally, you want to cut the sunflower head when the petals are starting to wilt but the back of the sunflower head is still mostly green.