Q: Last year my mums grew tall and spindly. Is there something I can do to prevent this from happening again this year?
A: Hardy chrysanthemum plants can grow 1 to 3 feet tall, depending on the cultivar, with a spread sometimes equal to the height. To keep them growing optimally, they should be planted in a full-sun location that receives at least six hours of direct sun per day. Plants requiring full sun that are planted in shady areas will often stretch for more sunlight and grow straggly. The soil should be well-drained and kept slightly moist.
Tall hardy mums will also need to be pinched back beginning in late spring when the plants are about 6 inches tall and continued every two to three weeks. Regular pinching will keep them compact and prevent them from growing too tall; however, plants should not be pinched later than the Fourth of July to assure good bud development and gorgeous blooms before the threat of freezing fall or winter temperatures. Shorter varieties will not need pinching to keep plants compact, but pinching can be done to delay flowering.