I have Imperial pink, Pied Piper, and Lemon Twist cosmos growing in my garden. The more I deadhead them the shorter the plants get. If I let them go, will they stop blooming? |
Removing the spent blooms from cosmos will encourage the development of additional blooms. If you leave the flowers on the plant, most of the energy will go into developing seeds instead of producing more flowers. Keep those spent flowers cut off and your cosmos will continue to grow and set new flowers all summer and into the fall months. |