Everything you need to know about growing beautiful mums

With the exception of roses and orchids, chrysanthemums are probably the most universally recognized flowers in the world. They’re a national symbol of Japan, and for years they were the bestselling florist potted plant crop in America.

Chrysanthemums are a part of our lives. What would football season be like without those big corsage mums!

Rather than just a brief overview of this venerable plant, it might be nice to explain applicable terms, as well as give some tips on how you can succeed with your mums.

Chrysanthemums need full sunlight, and they bloom best when they’re grown in well-prepared garden soil (several inches of organic matter and one inch of expanded shale, rototilled 10 to 12 inches into the soil).

Mums are perennials. The plants die to the ground with the first freeze, but you can actually cut them back to within an inch of the soil as soon as the flowers turn brown.

Chrysanthemum "flowers" are actually floral heads. Like sunflowers, zinnias, marigolds and asters, mums are composites. What we call their flowers are actually composed of hundreds of small, individual flowers.

As you delve into mums, you’ll find terms that refer to their flowering forms. Single, or daisy-form mums have a row of outer flowers with a yellow center. Anemones have one or more rows of flattened outer flowers, with a pincushion of inner flowers. Decoratives catch many of more conventional, fully double-flowering potted and garden mums. Quills, spoons and spiders have greatly elongated "petals" that give a wispy look to the oversized heads.

We train the mum plants and their floral sprays several ways. Plants you see in full bloom right now in area garden centers are called garden, or cushion mums. That’s because they are the best types for planting in our perennial gardens and because the plants look like colorful pincushions while they bloom.

Florists sell several different types of mums, but chief among them are potted mums (grown and sold in containers), pompoms (sprays of 15-20 flowers and buds) and huge corsage mums that may be 6 to 8 inches across.

Two terms require explanation at this point: "Pinching" refers to using your thumbnail and index finger to snip/snap the growing tip from the plant. That causes side branches to develop, keeping the plant more compact. "Disbudding" is the practice of removing all of the side buds that form along the stems of each plant. We do that with potted mums, and we certainly do it with the big football types, so that all of the water and nutrients can be directed into the one huge floral head.

Mums thrive in the dark

Chrysanthemums are photoperiodic. That’s a botanist’s way of saying that they measure the length of the night to determine when it’s time to bloom. The flower-inducing hormone is destroyed by light, so nights have to be 14 hours long (without ambient light) before the plants will begin to set their flower buds. Security lights and even strong landscape lighting can keep some or all of the plants from blooming properly. Moonlight is not a concern.

Growers talk about different varieties’ response groups. Some types are more sensitive to lengthening nights, and those types tend to flower earlier. That’s why garden mums will bloom 6-8 weeks earlier than many others. For example, if you plant a potted mum from the florist shop into the garden, it will certainly come back each year. But, it won’t bloom until November, and if you don’t pinch it monthly in spring and summer, it will grow 24 to 30 inches tall.

Chrysanthemums are grown from either cuttings or by division. Cuttings should be rooted in the spring, from the first flush of new growth. You can probably get a second round of cuttings from the regrowth that springs up where the original cuttings were taken.

Division is far simpler. Use your spade to lift part or all of a clump, then cut it into smaller sections, each with its own set of roots. You can divide mums in the fall, although the new plantings will need a little special attention to watering to get them through the winter in good condition. You also can dig and divide mums in late winter, before the burst of new spring growth. The shoots grow with a vengeance, however, so don’t let time slip away from you.

Neil Sperry publishes Gardens magazine and hosts Texas Gardening radio show from 8-11 a.m. Saturdays and Sundays on KRLD/1080 AM. Reach him during those hours at 214-787-1080.

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