Garden mums are a beloved feature of the autumn landscape, providing a burst of saturated color when most other plants are fading. These compact, dome-shaped plants are widely available in fall, making them a fixture of seasonal decorating on porches and in garden beds. They are commonly known simply as mums, offering a dense display of vibrant blooms in shades of yellow, red, orange, and purple.
Defining the Garden Mum
The garden mum belongs to the genus Chrysanthemum, which is part of the large daisy family, Asteraceae. The varieties most frequently sold today are complex hybrids, often categorized under the species Chrysanthemum x morifolium. It is important to distinguish the “garden mum,” sometimes called the “hardy mum,” from the “florist mum.” Garden mums are specifically bred for their ability to survive cold winters and return the following year as perennials. Florist mums, while technically the same species, are typically grown for a single season, lacking the necessary root structure and cold tolerance for reliable perennial growth. The hardiness of a garden mum depends significantly on its ability to establish a robust root system before the ground freezes.
Essential Care and Placement
For optimal growth and abundant autumn blooms, garden mums require a site that receives a minimum of six hours of direct sunlight each day. Full sun promotes strong, non-leggy stems and maximizes flower production.
The soil must be well-drained, as these plants are highly susceptible to root rot if they remain in perpetually soggy conditions. Consistent moisture is necessary, especially when plants are newly established or temperatures are high. Water thoroughly when the top inch of soil feels dry, checking daily for container-grown specimens.
Watering directly at the base of the plant avoids wetting the foliage, which helps prevent fungal diseases. Removing spent flower heads, a practice known as deadheading, encourages the plant to develop new buds.
Overwintering for Perennial Survival
The best chance for perennial survival occurs when garden mums are planted in the ground during the spring, allowing their roots to become well-established throughout the growing season. Mums purchased and planted late in the fall have a lower survival rate because the plant dedicates its energy to flowering rather than root development before winter. To prepare the plant for dormancy, wait until after the first hard frost, which signals the end of the blooming period.
Resist the urge to cut the stems back immediately, as the remaining foliage helps insulate the plant’s crown through the winter.
After the ground has frozen solid, apply a thick layer of loose, airy mulch, such as straw or pine needles, about three to four inches deep over the plant’s crown. This mulch is not meant to keep the plant warm, but rather to maintain a consistently cold temperature in the soil, preventing the damaging cycle of freezing and thawing that can push the plant out of the ground. In the spring, once new growth appears, remove the protective mulch layer and cut the old, dead stems back to a few inches above the ground.
Understanding Flower Types and Varieties
The visual diversity of garden mums is categorized by the shape and arrangement of their ray and disc florets within the flower head. Common forms include the decorative type, which has flat-headed blooms with long, overlapping ray florets. Cushion mums are characterized by a low, mounding, and dome-shaped growth habit that covers the plant almost completely with flowers. Pompom varieties feature small, spherical, and tightly rounded flower heads that resemble a button, with the central disc florets completely hidden. Other classifications include the reflexed type, where the ray florets curve downward and outward, and the incurved type, where the florets curve inward to form a globe shape.