As soon as the first few cool nights arrive in late August, thoughts of fall mums come to mind. Big pots of colorful mums for the front steps, more for the back porch, and of course, some to fill in the few bare spots in the garden.
Lucky for us, fall is a long, glorious season in upstate New York and mums are as much a part of the mix as are apples, corn stalks and pumpkins. The mums that we purchase are perennial varieties, but many gardeners complain that the ones they plant in the fall just do not come back reliably, and if they do, they rarely look the way they did the first year they were planted. So what’s a gardener to do? When you purchase fall mums try to buy from local growers, that way the only travel that your plants experience is the trip home in your car. Many people look only for size and color, but consider also the bud stage and buy plants that are mostly in bud, just beginning to show color. If you are buying several plants, ask the salesperson to help you choose varieties that are early, mid-season and late blooming to prolong the fall "show time".
Look for Belgian varieties (the tag in the pot will designate this) as they have been developed to have a naturally tight-mounded shape with no pinching or staking needed. They have many more blooms per plant than traditional varieties and they are more flexible so there is less breakage.
Many homeowners want to use fall mums decoratively to line porch steps or patios, or to change out planters of summer annuals. In these cases, it is best to consider these mums as annuals and discard them when they are done blooming.
The mums that are planted in the ground stand the best chance of becoming perennial by being planted as soon as possible after purchase. Mums are very intensively grown, so always check for swirling roots and gently tease them out before planting to encourage rooting out into the soil. This time to root out or get established in the garden is crucial to the mum becoming perennial as it is much less likely to heave out of the ground with the freezing and thawing of winter. Do not fertilize this first fall as the grower has done this for you. While traditional mums are not cut back until spring, the Belgian types are cut back in the fall and mulched well after the ground has begun to freeze. They often bloom in early spring and are then cut back once, fertilized well, and allowed to grow on to re-bloom in fall. Remember that they are genetically wired to grow in a mounded tight shape.
Traditional mums are fertilized and then cut back several times in spring until mid-July when they are allowed to grow on until they bloom. The maintenance chores with the non-Belgian types are greater and the end result more variable. Even after all the cutting back, many traditional mums are still tall and floppy by fall.
Perhaps this is the fall to try something new and plant some Belgian mums in your garden. Don’t be mum on this beauty – spread the word!
Susan Pezzolla is community educator for Horticulture at Cornell Cooperative Extension Albany County.