Chrysanthemums, commonly known as mums, are classified as indoor or outdoor plants depending on the specific variety and the gardener’s intent. The majority of mums are categorized into two main types: hardy garden mums and florist mums. While garden mums are technically herbaceous perennials capable of surviving winter, both types are most frequently purchased as temporary, vibrant seasonal decor. Mums are primarily hardy outdoor plants often used as short-term indoor accent pieces.
Seasonal Outdoor Display
The classic fall chrysanthemum display uses the plant in outdoor containers and garden beds to provide color as other plants begin to fade. Successful growth requires a location that receives full sun, meaning at least six hours of direct sunlight each day. Proper water management is necessary, as mums are thirsty plants that require consistently moist soil without becoming waterlogged. The soil must be well-draining because standing water quickly leads to root rot.
The two main categories, hardy garden mums and florist mums, have different outdoor performance expectations. Hardy mums are specifically bred to survive the winter in USDA zones 5 through 9, developing a robust root system when planted early in the season. Florist mums, often sold in grocery stores, are bred for maximum bloom density, which comes at the expense of a strong root structure. These florist varieties are most often treated as annuals and are not expected to survive the winter, even when planted outdoors.
Care for Indoor Potted Mums
Bringing a potted mum indoors is best viewed as a temporary measure to enjoy their vibrant blooms as a short-term houseplant. Unlike many foliage plants, chrysanthemums prefer cooler temperatures, ideally between 60 and 70 degrees Fahrenheit, which helps extend their blooming period. Placing the plant near a bright window that receives indirect light is best, as direct, intense midday sun can cause the flowers to fade quickly. Insufficient light will cause the plant to decline rapidly.
Indoor mums should be watered frequently, generally when the top inch of the soil feels dry, ensuring the pot has drainage holes to prevent saturation. Water the soil at the base of the plant, avoiding the foliage, which helps prevent fungal diseases. Because these plants are coaxed to bloom heavily, they are poor candidates for long-term indoor survival and rarely re-bloom successfully. Many gardeners compost the plant once the blooming cycle is complete.
Ensuring Outdoor Survival Through Winter
To successfully transition a hardy garden mum into a returning perennial, the timing of planting is a significant factor. Mums should be planted in the spring to allow their roots a full growing season to establish before the ground freezes. Fall-purchased mums often lack the necessary root development to survive their first winter outdoors, even if they are a hardy variety. Planting them in a site with excellent drainage is paramount, as cold and soggy soil is lethal.
Once the foliage has been killed by hard frosts, the stems should be cut back to about three to four inches above the soil line. Leaving the dead growth in place until early spring provides natural insulation and protection for the crown of the plant. After the ground has frozen solid, apply a thick, insulating layer of mulch, such as straw or shredded leaves, over the planting area. This heavy mulching prevents damaging freeze-thaw cycles that can heave the plant out of the soil and damage its root system.