The chrysanthemum, or “mum,” is a garden favorite, celebrated for its burst of color in the autumn landscape. Many gardeners wonder if their plants will return the following spring. A mum’s survival and timing of re-emergence depend on the specific variety planted, the local climate, and the care provided during the preceding fall and winter. Understanding these factors increases the likelihood of seeing new growth each year.
Perennial vs. Seasonal Mums: Identifying the Returners
The primary distinction determining a mum’s return is the difference between “florist mums” and “hardy garden mums.” Most plants purchased in full bloom in the fall are florist mums, which are treated as annuals because they lack the cold hardiness to reliably survive winter outdoors. These varieties have shallow roots and are bred for bloom size and color, not perennial resilience.
Hardy garden mums, often Chrysanthemum x morifolium, are bred to withstand winter temperatures in USDA Hardiness Zones 4 through 9. These perennial types establish a deeper root system and reliably re-emerge when planted directly in the ground. Gardeners should seek out cultivars specifically labeled as “hardy” or “garden mums” at the time of purchase to increase success.
Timing of Spring Emergence and New Growth
A hardy mum’s spring emergence is determined by the soil temperature, making the timing variable across regions and years. New growth is triggered when the soil warms sufficiently, generally reaching 40°F to 50°F. This usually occurs two to four weeks after the last significant frost has passed.
In warmer climates (Zone 7 and above), new growth can appear as early as late March. In colder regions (Zones 4 and 5), new shoots are often delayed until late April or mid-May. Successful overwintering is indicated by small, green shoots emerging directly from the base of the plant, known as the crown. Look for this fresh growth at the soil line, not on the old, woody stems.
These new shoots signal that the root system has survived and is beginning the new growth cycle. The old stems above the ground are dead and will not produce new foliage or flowers. A sheltered location or thick winter mulch can slightly influence the exact moment of emergence by affecting how quickly the soil warms.
Essential Spring Care for Successful Overwintering
Once new green shoots are visible around the crown, spring care begins with cleanup and pruning. Cut the old, dead stems from the previous year back to approximately three to four inches above the ground. This removal clears space for new growth, improves air circulation, and helps prevent fungal diseases.
Pinching for Bushier Growth
The most important step for a full fall display is “pinching” or “stopping.” Pinching involves removing the top half-inch of new growth when the plant reaches six to eight inches tall. This disrupts the plant’s natural tendency to grow tall and straight, stimulating the development of lateral branches instead.
This repeated removal forces the plant to become bushier and more compact, preventing it from becoming tall and leggy. The initial pinch should be followed by subsequent pinching every two to four weeks as side shoots reach six to eight inches. The final pinching must be performed by early to mid-July, as pinching later will delay bud formation and risk losing flowers to early frost.
Watering and Fertilizing
During active spring growth, the plant requires consistent moisture to support rapid development. Mums need regular watering in the spring to establish a strong, healthy root system. A light application of a balanced, slow-release fertilizer in early spring, or a liquid feed monthly, provides necessary nutrients. These care steps ensure the plant develops the structure needed for a spectacular display when autumn triggers blooming.