Chrysanthemums, commonly known as mums, are popular flowering plants often purchased in autumn for their vibrant colors. While frequently treated as temporary seasonal decorations, many varieties are perennial and can thrive year after year with proper attention. Achieving long-term survival and encouraging reblooming requires understanding their specific environmental needs and adapting care routines throughout the changing seasons. This guide offers practical instruction for maintaining the health of chrysanthemums well beyond their initial flowering period.
Establishing the Right Environment
Long-term success begins with identifying the type of chrysanthemum purchased. “Florist mums” lack the cold hardiness needed to survive winter outdoors and are often treated as annuals. In contrast, “Hardy Garden Mums” are genetically resilient, capable of entering dormancy, and returning in the spring, making them the appropriate choice for year-round cultivation. When selecting a plant, choose one with tight buds just beginning to show color, as this indicates a longer potential flowering period.
Mums require a location that receives a minimum of six hours of direct sunlight daily for robust growth and abundant flowering. Insufficient light results in weak stems and fewer flower buds. Soil composition is equally important; mums thrive in well-draining conditions and suffer from root rot if waterlogged. Planting in the ground with amended soil is generally preferable, as it allows for a stronger root system than container planting.
If container planting is necessary, select a pot with ample drainage holes and use a quality potting mix that drains well. Planting mums in the spring or early summer allows the roots sufficient time to become established before the stress of the fall blooming season and winter dormancy.
Routine Care: Watering and Feeding
Consistent watering is paramount during the active growing season to prevent root stress. Focus the water directly onto the soil surface, avoiding wetting the foliage, which can encourage fungal diseases like powdery mildew. Mums prefer consistent moisture, so water deeply when the top inch of soil feels dry. Container plants require more frequent watering than those planted in the ground.
During the spring and early summer growth phase, mums benefit from regular feeding to develop strong structure. A balanced, all-purpose fertilizer, or one slightly higher in nitrogen, encourages lush green leaves and strong stems. Apply fertilizer every two to four weeks, following dilution instructions carefully to avoid burning the roots.
As mid-summer approaches, shift the feeding regimen as the plant prepares to initiate flower bud formation. Transition to a fertilizer lower in nitrogen and higher in potassium to support the energy demands of flowering. Cease all fertilization completely by late summer or early fall so the plant can slow its growth rate and harden off tissues for winter dormancy. Over-feeding late in the season can result in tender new growth easily damaged by cold temperatures.
Ensuring Survival Through Seasonal Changes
Managing the plant’s growth habit through selective tissue removal impacts both flower production and structure. “Pinching” is the removal of new growth tips, typically beginning in the spring when shoots are four to six inches tall. This action forces the plant to branch out, resulting in a denser, bushier plant with more flowers. Continue pinching every two to three weeks until approximately the Fourth of July.
Stopping the pinching process allows stems to mature and set flower buds in response to shortening day length. Once flowers have faded, “deadheading” (removing spent flower heads) can improve the plant’s appearance and may encourage a small secondary flush of blooms. Deadheading is primarily cosmetic and does not alter the plant’s preparation for dormancy.
Preparing the hardy mum for winter is essential, as the plant must enter dormancy to survive freezing temperatures. Unlike many perennials, leave the stems intact over the winter, cutting them back only after the first hard frost or when the foliage has completely died back. Cut the stems down to about four to six inches above the soil level to provide protection for the crown.
Once the ground has frozen, apply a thick layer of organic mulch, such as straw or shredded leaves, over the plant’s crown. This insulation prevents repeated cycles of freezing and thawing, which can heave the plant out of the ground and damage the roots. For container-grown hardy mums, move the pots into a sheltered, unheated location, such as a cool garage, where temperatures remain cool but above freezing. Ensuring good winter drainage prevents the crown from sitting in cold, waterlogged soil, a common cause of winter death.