Chrysanthemums

Chrysanthemums, which some of you know, are native to China but they are also revered by the Japanese. They are probably considered as one of the most popular plants in temperate climate zones around the globe. They are beyond compare in the garden for their late-summer and fall blossoms. Most chrysanthemums will flower anywhere from three to eight weeks with the flowers ranging from small buttons to extensive globes that can measure up to 8 or more inches across.

They are not only beautiful in the garden, but hobbyists delight in chrysanthemums because they can be grown not only outdoors but also in the greenhouse. There are some hybridists that have developed many varieties that can be induced to bloom at any time, particularly in the greenhouse. These varieties can vary tremendously from their common ancestors. There are many greenhouse gardeners that grow mums specifically to enter in flower shows.

For the most part, chrysanthemum plants are short-day plants; their blooming times are triggered by the shortened days of late summer. It is at this time that the plants' energies turn from vegetative growth to production of flowers; this usually appears around six weeks after the buds appear. Some varieties may need up to 12 weeks of short days before they bloom.

Some gardeners wish to control the process of blooming and there are several methods to achieve this. Special lighting and shading techniques can entice the plants to bloom at almost any time. But it is also important to know the elapsed time, or response time, from when the buds first appear to when the flowers bloom for each variety.

Low-growing, plants are usually in the six- to seven-week elapsed time group. The 8-, 9-, and 10-week groups include all the flower forms. But the varieties in the 11- and 12-week group usually are grown in the greenhouse, but these will even bloom outdoors in some areas. If the outdoor temperature drops much below 32 degrees F, the buds and flowers will be damaged unless we take the precaution to protect them. Usually a plastic cover over a plant will often work; but an open shelter will most likely keep the temperatures 4-6 degrees higher than outside.

The "hardy chrysanthemums" term is used to describe the low, bushy type of plant can be a little misleading. The roots of all perennial mums are capable of handling temperatures slightly below freezing, but it is the alternate freezing and thawing that causes most winterkill because it causes the shallow-rooted plants to lift out of the ground.

To prevent this from happening we can dig up the plants after they have bloomed and to store them in a cold frame, or to store the plants on the along the north side of a building, in pots, and cover them with straw. If the mum plants' soil is very well drained, we can leave them were they are but cover them with a few inches of mulch after the ground freezes.