08-03-2026, 04:59 AM
Deadhead cosmos flowers regularly throughout the summer and fall to encourage them to keep producing flowers instead of seeds. This helps the plant to put its energy into producing new flowers rather than seeds. Other factors that help promote continuous flowering include planting cosmos in full sun and not over fertilizing. Lightly cut back (about 1/3 of the plant) midsummer if they become too tall and spindly. They promote bushier growth and in some instances produce a new crop of colorful flowers later in the growing season.