Chrysanthemums or ‘Mums’ are an old standby in the autumn garden. They are everywhere in the fall. While mums will stay in flower for weeks, many gardeners do not realize there are hardy perennial mums that can be planted in the garden and only improve with age.
The garden chrysanthemum is one of the most exciting flowers that can be grown in the home landscape for late summer and fall display. Garden mums require a minimum amount of care and do well even under some adverse conditions. There are cultivars (varieties) with color that range from white to yellow, pink, bronze, red and their hues. With hundreds of cultivars available, the choice of plants to grow is unlimited. To have a more interesting collection of mums, however, plant cultivars of various types such as singles, anemones, decoratives, pompons, spoons, spiders and standards.
The key to a truly hardy mum is selecting the right variety and giving it time to establish itself in the garden before cold weather sets in.
In cold climates leave the foliage on the plant until spring. Mulch heavily around the plants after the first heavy frost and the plants have died back.
Another option is to physically move the plants. Do this before the first hard freeze. For already established mums, don't fertilize them after July. This will reduce the amount of new growth that may be damaged by cold.
Nurseries are loaded with mums for sale in the fall. These plants have been specially grown to set buds for September blooms. This forces a lot of energy into blooming and not much into growing roots. Planting these fall mums out in the garden in late summer or early fall usually doesn’t guarantee enough time for plants to become established enough to survive the hardships commonly found in cold climates. This isn't a problem in warmer climates, where a bit of deadheading will satisfy most mums after bloom. For colder climates, freezing and thawing of the soil will heave the plant out of the ground and most likely kill the plant. That's why it's important to heavily mulch your mums to prevent this heaving. Mulching will help regulate soil temperatures.
If you don't want to bother with trying to save your mums from year to year, they can be grown as annuals. They do provide wonderful fall color and work great at filling in empty spots where summer bloomers have faded. Look for plants with lots of unopened buds, to have blooms well into the fall season.
Today's chrysanthemums are highly evolved flowering plants. A member of the Asteracea (Compositae) family, the chrysanthemum (dendranthema) is related to dahlias, sunflowers, marigolds, zinnias and cosmos. The bloom which appears as a single flower is actually hundreds of flowers called florets. Two kinds of florets are present in a single bloom, disk florets and ray florets. On a daisy type chrysanthemum the outer parts are ray florets and the center or eye is composed of disk florets. For ease of identification the National Chrysanthemum Society divides bloom forms into 13 classes:
|Irregular Incurve||These are the giant blooms of the chrysanthemum genus. The florets (petals)loosely incurve and make fully closed centers. The lower florets present an irregular appearance and may give a skirted effect.|
|Reflex||The florets in this class curve downward and overlap, similar to bird plumage. The tops of these blooms are full, but somewhat flattened.|
|Regular Incurve||A true globular bloom equal in breadth and depth. The florets smoothly incurve and form a ball.|
|Decorative||A flattened bloom with short petals. As in classes 1-3 the center disk should not be visible. The upper florets tend to incurve, but the lower petals generally reflex.|
|Intermediate Incurve||This bloom class is smaller than the irregular incurve, with shorter florets, only partially incurving with full centers, but giving a more open appearance. Many of the popular commercial incurving types are in this intermediate class.|
|Pompon||A small globular bloom, somewhat flat when young but fully round when mature. Size ranges from small button types to large disbudded blooms almost 4 inches in diameter. The florets incurve or reflex in a regular manner and fully conceal the center.|
|Single and Semi-Double||A daisy-like flower with a center disk and one or more rows of ray florets.|
|Anemone||These blooms are similar to the semi-doubles, but have a raised cushion-like center.|
|Spoon||Essentially the same as the semi-double, except the ray florets are like spoons at the tips. The center disk is round and visible.|
|Quill||The florets in this Class are straight and tubular with open tips. The bloom is fully double with no open center.|
|Spider||Spiders have long tubular ray florets which may coil or hook at the ends. The florets may be very fine to course.|
|Brush/ Thistle||Fine tubular florets which grow parallel to the stem and resemble an artist's paint brushes or in the thistle form the florets are flattened, twisted and dropping.|
|Unclassified||Those blooms which fit in none of the other classes. They are often exotic, with twisted florets. They may also exhibit characteristics of more than one bloom class.|
Mums need at least a half day of sun for good bloom, but full sun is best. Mums set buds in response to day length, so avoid confusing them by planting where they may be exposed to bright night time light.
Best if planted in the spring and allowed to become established. They refer a rich, well-drained soil, slightly on the alkaline side. Feeding every 3-4 weeks until buds set will improve flowering.
An important cultural practice with garden chrysanthemums is applying adequate amounts of water. During some summers, rainfall may be plentiful enough to eliminate most additional watering. However, the plants should be watered when the soil starts to dry. Apply enough water to soak the soil to a depth of 4" — 6". This is best done by using sprinklers rather than hand watering. It is best to apply the water during the day so the foliage will dry off before nightfall. Otherwise, leaf and flower diseases can become a problem.
To promote a sturdy, bushier plant with lots of blooms, pinch off the top 1" — 2" of growth once taller varieties are at least 6" high; shorter varieties 4" — 5" high. Continue pinching the tips every 3 - 4 weeks until early July in cooler climates, the end of July in warmer Zones.
Deadheading is only necessary in warmer climates where the plants remain green. In areas with freezing winters allow the foliage to remain until spring. This improves the plant’s chances for survival. During cold, snowless winters, mulching will be necessary. Even then, there’s no guarantee all your mums will make it, especially those planted in the fall.
If mums have not been hardy in your area, you could try potting them and moving them to a more protected area of the garden for the winter and return them to their intended spot in the spring.
Established mums can be divided every 2 - 3 years in the spring as necessary.