Chrysanthemums, commonly known as mums, are a popular choice for adding saturated color to the garden as summer blooms fade. They provide a beautiful transition into autumn, offering hues of yellow, bronze, red, and purple. Successfully establishing these plants requires careful consideration of the planting schedule, especially if the goal is for them to return year after year.
Optimal Timing for Planting Mums
The best window for planting mums depends on whether the goal is perennial establishment or immediate seasonal color. For the highest likelihood of the plant surviving winter and returning the following spring, planting should occur in late spring or early summer. This timing, ideally after the last threat of a killing frost has passed, provides the root system with several months to expand and anchor itself firmly in the soil before the ground freezes. A well-developed root mass allows the plant to withstand the freezing and thawing cycles of winter weather.
Gardeners seeking immediate visual impact often purchase mums in full bloom during late summer or early fall. If planting these flowers in the ground, it should be done at least six to eight weeks before the average date of the first hard frost in the region. This short period allows for some minimal root settling, but the plants are primarily focused on flowering rather than root development, which reduces their chances of overwintering success, especially in colder climates.
Site Selection and Soil Preparation
Light Requirements
Mums require full sun to thrive. A location that receives a minimum of six hours of direct sunlight daily promotes stocky growth and abundant blooms. Insufficient light results in weak, elongated stems and fewer flowers.
Soil Requirements
The composition of the soil is equally important because mums are susceptible to root rot if left in saturated conditions. They perform best in well-drained soil that remains consistently moist but never waterlogged. Before planting, work the soil to a depth of 6 to 12 inches to improve its structure. Integrating organic matter, such as compost or peat moss, helps achieve the ideal texture for drainage and moisture retention.
Step-by-Step Planting Guide
The planting process begins with digging a hole two to three times wider than the mum’s root ball. Widening the hole, rather than deepening it, ensures the roots can easily spread horizontally into soft, prepared soil. The top of the root ball must sit level with the surrounding garden soil.
Before placing the plant, gently loosen any tightly bound roots on the exterior of the root ball. This encourages the roots to grow outward into the new soil. Placing the plant too deep can lead to water pooling around the stem, increasing the risk of stem rot.
Once positioned, backfill the hole with the amended soil, lightly firming it around the roots to eliminate air pockets. Proper spacing is necessary for good air circulation, which helps prevent disease. Mums should be spaced approximately 18 to 36 inches apart, depending on the variety’s mature size. Immediately after planting, water thoroughly to settle the soil and hydrate the roots.
Ensuring Mums Thrive Beyond the First Season
Pinching and Feeding
Long-term maintenance starts with pinching, a technique that encourages branching and a compact, bushy habit. Begin in the spring when new growth is about six inches tall by removing the tender tip of each new shoot. Repeat this process every few weeks throughout late spring and early summer. Cease all pinching by early to mid-July, as later pruning removes the developing flower buds needed for fall color.
Throughout the growing season, mums require consistent moisture, especially during dry spells, and benefit from regular feeding. Apply a balanced fertilizer, such as a 10-10-10 formulation, monthly until the flower buds are visible, then stop fertilization.
Winterizing
Preparing hardy mums for winter involves leaving the dead foliage intact after the first hard frost instead of cutting it back. The dead stems and leaves provide insulation that protects the plant’s crown from extreme cold. Once the ground has solidly frozen, apply a four- to six-inch layer of mulch, such as straw or shredded leaves, to further insulate the shallow root system, improving the chances of spring return.