by – Linda Geist, University of Missouri Extension
They are big, beautiful and bold. Their show-stopping flowers pack a wallop of color.
Few flowers signal fall’s arrival more than the cheerful chrysanthemum, mum for short, says University of Missouri Extension horticulturist David Trinklein. Mums’ long-lasting blooms show off for weeks, long after other flowers have clocked out for the season.
Not only are mums marvelous for fall decorating, but they also come with a history. Mums are one of the oldest known flowers.
The Chinese raised them for ornamental and medicinal purposes more than 2,000 years ago. The Japanese emperor placed the chrysanthemum on his country’s official seal in the eighth century. Families used a mum insignia on family crests to boast of prominence. In ancient Japan, Japanese warriors etched images of mums onto their swords. In other cultures, they serve as grave decorations, and they are November’s official flower.
Now new varieties developed by plant breeders are making mums more popular than ever, Trinklein says.
A myriad of new colors, flower types and bloom dates abound each year. Mum lovers delight in new cultivars with improved growth habits and garden performance. A relative newcomer, the Belgium or European garden chrysanthemum, is a popular choice because of its spectacular size and showy color.
Chrysanthemum is a ‘cultigen,’ Trinklein says. It has six sets of chromosomes, instead of the normal two. This makes mums sterile. “If not for human intervention, mums as we know them today would not exist,” he says. Plant breeders also work to produce plants to bloom at specific times. Mums need long periods of darkness each day to be induced to bloom. In the past, many bloomed in mid- to late- summer, depending on cultivar and temperature. Many of today’s popular cultivars bloom between late September and mid-October. “Because of the cooler temperatures at this time of the year, they tend to remain attractive longer,” Trinklein says.
Garden mums are available in the spring as rooted cuttings established in small containers or during the fall as large, mature plants in or near full-bloom.
Trinklein shares several tips for maintaining successful mums in the garden.
For spring mums:
- Select a well-drained planting site that receives at least eight hours of sunlight.
- Space smaller plants far enough apart — 18 to 24 inches — to allow for the future growth. Space 30 to 36 inches apart for more vigorous cultivars.
- Apply a granular fertilizer such as 5-10-5 or equivalent at the rate of two or three pounds per 100 square feet of surface area, and mix it into the soil. Apply a soluble starter fertilizer high in phosphorus (e.g. 15-30-15) immediately after transplanting.
- Pinch spring-planted garden mums every three to four weeks for bushy, compact growth and more flowers. For most, pinch no later than July 4 to avoid removal of flower buds.
- Garden chrysanthemums need about 1.5 inches of water weekly during the growing season.
- Mulch plants with bark, wood chips or other organic materials. This saves moisture and controls weeds.
- Check for aphids, two-spotted mite and powdery mildew. Garden chrysanthemums are mostly insect and disease free.
For fall mums:
- Choose plants that are beginning to show color. These produce blooms for the longest time. Expect bright colors even after light frosts and the colors to fade after heavy frosts.
- Most potted mums grow in soilless growing medium high in organic matter. Plant in well-drained soil in the garden or flowerbeds. The roots of fall-planted mums find it hard to adapt to heavy garden soils when planted.
- After transplanting, water to nourish and establish roots but avoid applying fertilizer.
- Prevent winterkill by mulching.
The National Chrysanthemum Society has 35 chapters across the nation. For more information, visit the Society’s website at www.mums.org.