Chrysanthemums

The garden mum 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. 

Garden chrysanthemums can be planted in spring or fall.  Oftentimes, garden mums grown for spring sales have been forced into bloom.  After the spring flowers fade, prune the plants back to one-third to one-half of their flowering height and they will bloom again in the fall.

If you purchase garden chrysanthemums late in the summer for a fall display, plant them at least six weeks before a    killing frost so that the plants can become established.  When selecting a planting site, choose an area that receives full sun and is several feet away from street lights or other night lights.  Exposing the plants to light during the night may   inhibit flower formation. 

Chrysanthemums grow best in moist, well-drained soils.  Avoid poorly drained, wet spots.  Before planting, work the soil to a depth of 8 to 12 inches and incorporate 2 to 4 inches of organic matter, such as peat moss, well-rotted manure, or compost.  Plant them 18 to 24 inches apart to give them room to develop into full, mound-shaped plants.  Plant to the same depth they were growing in their containers and no deeper.  The plants should be thoroughly watered after planting.  Keep chrysanthemums well watered throughout the season.  No fertilization is necessary for fall-planted mums.

Several things can be done to increase the chances that your mums will survive the winter.  First, avoid planting mums in areas subject to cold, dry north winds.  If you are taking care of mums that have gone through a fall planting and spring season, stop fertilizing the plants by the end of July to discourage late season growth.  Don’t prune plants back in fall.  Research has found that garden mums survive the winter better if the old foliage is left standing through the winter.  Mulching is the best insurance for     over-wintering mums.  It helps keep the soil uniformly cold after it has become frozen, thus eliminating the alternate freezing-thawing cycle and the resulting soil heaving.  Apply 4 to 6 inches of straw, pine needles, or other mulching material in late November or early December.  Leaves are less suitable as a mulch because they tend to pack solid when wet.

The Art of Pinching

Want more flowers?  Gardeners who complain that their chrysanthemums are tall and leggy with few blooms haven’t learned the art of pinching—periodically removing the growing tips and first set of leaves.  Start in the spring when the new growth is 4 to 6 inches long.  Pinch all shoots every 2 or 3 weeks until late June; continuing longer will prevent flower formation.  New shoots should have the tops removed by pinching them off between the thumb and forefinger.  This   practice should be followed, leaving two or three leaves on the shoot, whenever it becomes three to four inches long.

Renovating the mum clump every 3 or 4 years also promotes healthy growth and continued flowering.  When new shoots appear in the spring, dig the entire clump.  Use a sharp spade to slice the clump into wedge-shaped sections, like a pie.  Remove and discard the point of the wedge (this is the oldest part of the clump).  Plant the remaining portion.

No Space in Your Garden?

With limited yard or no yard at all, chrysanthemums can be grown successfully in containers.  With containers, the soil can be formulated for good drainage and the containers can be moved to provide maximum sunlight and protection from the elements.  Plant with some winter pansies and ornamental cabbage or kale, for a spectacular fall color display.