After poppies are done blooming, what should I do with the dark brown heads – should they be cut off immediately, this fall, or not until next spring?
Once poppy flower petals have fallen, it is best to remove the seed head as soon as possible. Cut the flower stem as close to the base of the foliage as you can. Since the plant does not have to form seed, it can now spend its energy developing a larger, more vigorous plant for next spring.