All About Mums

Fall mums are great for perking up tired summer gardens and adding bright color to containers.  They also make fine cut flowers for indoor arrangements. The blooms will last for about a month, but in our climate fall planted mums should generally be regarded as annuals. You may, however, improve their chances of survival by following certain guidelines.

CHOOSING YOUR GARDEN MUM

Garden mums are usually available at different stages of flower opening, from tightly budded to fully open flowers.  Choose plants with more open flowers if you need instant color, or fewer open blooms if you want to enjoy them for a longer period of time. Regardless, choose healthy plants with dark green leaves and little flower or stem damage.  Well-grown mums have nicely rounded habits and are loaded with buds and blooms.  Try to avoid plants with an upright, narrow habit.

WHERE TO PLANT YOUR MUMS

Mums prefer a sunny location, therefore select an area that receives at least 5 to 6 hours of direct sunlight daily. The soil must also be well-drained, never soggy.  Do not plant in a site where soils are constantly moist or where standing water accumulates.  This can cause root rot and may be fatal.  If your soil is particularly heavy, amend it with course organic matter such as composted manure or leaf mulch.  You can provide better drainage by planting your mums on a gentle slope or in a raised bed.  Avoid planting at a site near a street light or other source of night lighting, which seems to delay the bloom time.  Plant mums at least 18 to 24 inches apart to provide good air circulation and to avoid mildew problems.

Maintenance

Garden mums generally require little maintenance.  Water your mums when nature does not provide enough rain.  Too much moisture is detrimental to the plants; not enough water will cause the leaves to dry out and the blossoms to have fewer petals.  Water your mums thoroughly right after planting.  In order to have that nice compact plant each fall season, you will need to pinch the plant back during the growing season.  As soon as new growth is 4 to 6 inches tall, use your thumbnail and index finger to “pinch” about half of the new growth at the top of every shoot.  Repeat this process through the summer when new shoots are 3 to 5 inches long, at least 3 or 4 times by mid-July (any later and you will either delay the bloom time or loose the flowers).  A diagram is included at the end of this handout.

Fertilizing

Do not apply fertilizer to your fall planted mums.  Fertilize in the following spring when you begin to see new growth.  Use an organic fertilizer such as compost, or a general purpose fertilizer such as 5-10-5.  Spread the fertilizer around the plant and work it into the soil.  Water thoroughly after fertilizing.  Repeat monthly until August.  Avoid using fresh manure.    

Insects and disease

Insects and disease are not a significant problem for garden mums.  In late spring, watch for aphids or leaf miners on the foliage.  If this occurs, apply a contact or systemic insecticide following the manufacturer’s recommendations.  The most common disease problems for mums are root rot, bacterial leaf spot, or wilt.  Look for discolored leaves, black lesions, or wilting foliage.  Some disease problems, if detected early, may be treated with a systemic fungicide.  Severe infections can be fatal to the plant so try to treat as soon as possible.  Good cultural practices such as providing good air circulation, proper spacing, and minimal overhead watering are the best prevention.

Winter Protection

Continue to water and keep the soil moist as winter approaches and throughout the winter when nighttime temperatures are above 30 degrees.  After blooms have faded in late fall, remove spent flowers but do not cut back the stems. Recent research has shown that mums have an improved chance of winter survival if they are not cut back. After a hard freeze mulch around the plants with a 4-6 inch layer of heavy, well-draining material such as coarse sand. This practice anchors the plants in the soil and minimizes the possibility of frost heaving.  After a mild winter, plants should reappear in spring.  At that time, trim back the old stems and gently move the mulch away from the plants.

PINCHING BACK MUMS

In order to have that nice compact plant each fall season, you need to pinch back the plant during the growing season. When new growth is about 6 inches tall, use your thumbnail and index finger to remove about half the new growth. Pinch back the main stem to two to three leaves.  Growth, called a “break”, appears above each leaf stem.  Pinch back each break to two good leaves.  Repeat this process through the summer when new shoots are 3 to 5 inches long, at least 3 or 4 times by early July (any later and you will either delay the bloom time or lose the flowers altogether).