Pinch mums – To get nice full mums this fall, pinch them back now. It’s best to pinch them two or three times before July 4, K-State Research and Extension horticulturist Dennis Patton says. Cut back new growth by half, preferably starting when the plant has four to six leaves below each stem’s top growth, Patton says. That will force the leaf axils below every cut to send out side shoots. The plant will be shorter but will end up with about six new stems wherever it used to have one.
“You repeat the process each time the new stems have put up about 4 inches of growth,” Patton says. “If you only cut them back by about half, your plant will be about 2 inches taller after every trimming. You quit around the Fourth of July, so the shoots will have time to put on new growth and set buds. They’ll be ready to bloom next fall.”
Gardeners with just a few mums can pinch them by hand or cut off the tops with scissors. They can follow the usual practice of cutting about one-quarter of an inch above a leaf. “That’s a little time-consuming and tedious, though,” Patton says. “If you’re a weekend-warrior-type gardener, you’ll find it’s a lot easier and faster to get out there with your hedge shears and chop them back. So long as you more or less keep the one-half rule in mind, that also will allow new shoots to break out and grow.
“If your plant’s healthy, each shoot should produce a fistful of flowers. So, by multiplying each stem several times, you’ll have that gorgeous bushy effect for the end of the season.”