Mums provide glorious color for the seasonal garden throughout autumn. Garden mums, originally from the Orient, are now grown all over the world for their wonderful display of colorful blooms. They are available in a wide range of colors with many variations of each hue. If the colors aren’t enough to choose from, these flowers come in many different shapes and sizes. By planting mums with early, mid and late-season bloom times, you can have an outstanding array of colors and textures from the end of August into November.
Are Mums Hardy? Annual or Perennial? Will they come back next year?
Mums are considered tender perennials. Whether they come back the next year depends on when and where they are planted:
Spring or summer – If planted in spring or summer, mums will have ample time to establish a good root system. If the soil is not too wet during the winter, they will overwinter just as other perennials. Mums will do best in raised beds or sandy soil.
September – If they are planted in September and the weather in September and October is warm, they can possibly overwinter as other perennials.
October – Mums planted this late in the fall season may not have time for their root systems to become established enough to survive the winter. If this is the case, enjoy your mums as annuals.
When planting mums, choose a sunny location with adequate drainage. Remove the plant from its pot and gently score the root balls to free the roots. Place them carefully in the ground, making sure not to plant them any deeper than they were in their original pot. Mums have surface roots and will suffocate if planted too deeply. Water with a transplant fertilizer such as Miracle Gro Quick Start or Bonide Root and Grow to stimulate root growth.
An area like New England will have sufficient rainfall most of the time to keep garden mums growing well. During dry spells, water them as needed to keep the plants from wilting; on average about one inch per week. Always thoroughly water in any freshly-planted garden mums.
Keep your garden mums’ soil moist as winter approaches. As the blooms fade, deadhead them to avoid having any stray seedlings come up. It’s best, however, to leave all the foliage in place until spring. Mulch the plants after several hard frosts with salt marsh hay or evergreen branches. In the spring, remove any old stems and gradually remove the mulch as your plants come to life again.
Don’t try to move them at this point, even if you don’t want them to stay where they are through the next growing season. Repeated freezing and thawing of the soil can heave plants out of the ground, exposing roots to the elements. Newly transplanted mums are especially vulnerable to heaving.
When growth resumes in the spring, carefully clear away the mulch and remove any dead foliage. This is the time to move them to a summer home if necessary. Replant the clumps in good quality soil which drains well; this is essential for healthy mums. Fertilize again with a transplant fertilizer.
Mums, being surface feeders, appreciate fertilizer applied as a top dressing. Around the end of May, scratch a granular fertilizer for flowering plants (such as GardenTone) into the soil around each plant. Apply granular plant food every four or five weeks until August or supplement with water-soluble fertilizer throughout late spring and early summer to encourage branching and bud formation.
To encourage branching and development of compact bushy plants, it is very important to pinch back young garden mums in the spring as soon as the new growth is 4-6 inches tall. Try to avoid damaging the little side shoots developing where the leaves meet the stem. On young, tender plants you would typically pinch with your fingernails. Narrow-bladed scissors or pruning shears can be used also.
Mums are stimulated to bloom by the declining day length of summer and early fall and to some extent a late-summer pattern of warm days and cooler nights. Pinching out the growing tips (even if they already have tiny buds) until about mid-July will make the plants bushier and keep them from trying to set blooms too early.