Learn how to grow chrysanthemums — from planting and pinching for maximum blooms to overwintering, dividing, and solving the most common mum problems every beginner faces.
Chrysanthemums — mums — are the undisputed stars of the fall garden. When nearly everything else is winding down for the season, mums explode with color: rich burgundies, sunny yellows, warm oranges, clean whites, and deep purples that carry the garden all the way to the first hard freeze. No other perennial delivers such spectacular late-season color with such reliability.
But here’s what many gardeners don’t know: the mums sold at garden centers and grocery stores every fall are often treated as disposable annuals — bought in bloom, displayed for a few weeks, and discarded. Grown correctly from early spring through a full growing season, those same plants become large, bushy, long-lived perennials that return with increasing beauty every year.
The secret is in the timing — specifically, the spring and early summer pinching that transforms a single-stemmed plant into a compact, densely-branched specimen covered in hundreds of blooms. At Outz News Garden, Maria Walker walks you through the complete chrysanthemum growing guide — from variety selection and planting to the pinching schedule, overwintering, and dividing that builds a spectacular fall display year after year. For the broader perennial garden context, see our guide to low-maintenance perennial flowers.
Understanding Chrysanthemum Types
According to Penn State Extension, chrysanthemums are one of the easiest perennials to grow — and hundreds of varieties provide a multitude of options for height, color, flower size, and time of bloom. Understanding the main categories helps you choose the right plants for your garden goals.
Garden Mums (Hardy Chrysanthemums)
Garden mums are bred specifically for outdoor perennial performance — cold hardiness, vigorous growth, and the ability to be pinched and shaped through the season. They are reliably perennial in Zones 4 to 9 when planted in spring with adequate time to establish roots before winter. These are the mums Maria recommends for permanent garden planting.
Garden mums are classified by flower form:
- Decorative (cushion) mums: fully double, globe-shaped flowers; the most widely grown garden type; compact and bushy habit — ideal for borders and containers
- Daisy mums (single flowers): open, daisy-like blooms with a yellow center surrounded by a single row of petals; excellent for pollinators; more informal appearance
- Pompon mums: small, perfectly round double flowers on compact plants; prolific and long-blooming
- Spider and spoon mums: long, tubular petals that curl at the tips; more exotic appearance; generally less cold-hardy than cushion types
By Bloom Time
- Early-flowering varieties (August to September) — ideal for short-season gardens and regions with early fall frosts; blooms before frost threatens
- Mid-season varieties (September to October) — the most widely grown; classic fall mum timing
- Late-flowering varieties (October to November) — maximum fall color but may be caught by early frosts in Zones 5 and colder
Hardy vs. Florist Mums
Florist mums — the large, perfect blooms sold year-round by florists and as gifts — are greenhouse-grown varieties bred for flower perfection, not cold hardiness. They rarely survive outdoors through winter. Garden mums are bred for cold hardiness and outdoor performance. Always choose varieties labeled “hardy” or “garden mum” for permanent landscape planting.
Site Selection and Soil Requirements
Full Sun — Essential for Best Blooming
Penn State Extension is clear: chrysanthemums need full sun — at least 6 hours of direct sunlight daily. In partial shade, mums become tall and leggy, produce fewer flowers, and are significantly more susceptible to the fungal diseases (particularly powdery mildew) that thrive in shaded, poorly ventilated conditions. Choose the sunniest available location for all chrysanthemum plantings.
Well-Draining Soil
Chrysanthemums are extremely intolerant of waterlogged conditions — their roots rot rapidly in consistently wet soil. Good drainage is their most critical soil requirement, particularly over winter when saturated, frozen soil is the primary cause of mum mortality in cold climates. If your soil holds water, amend with compost and perlite, or plant in raised beds.
Soil pH and Fertility
- Soil pH 5.5 to 6.5 — slightly acidic
- Moderately fertile soil enriched with compost — avoid overly rich soil that produces excessive leafy growth at the expense of flowers
- Work 2 to 3 inches of compost into the planting area before installing new mums
Air Circulation
Penn State Extension emphasizes that mums need air circulation and adequate drainage. Space plants 18 to 30 inches apart — chrysanthemums are susceptible to aphids and mildew, and keeping plants dry with good airflow is essential for disease prevention. Do not crowd mums against walls, fences, or other plants where air movement is restricted.
Planting Chrysanthemums for Perennial Success
When to Plant — Spring Is Critical
This is the most important chrysanthemum timing rule: plant in spring, not fall, for perennial success. Fall-planted mums purchased already in bloom invest all their energy in flowering rather than root development. They enter winter with shallow root systems that are easily killed by cold. Spring-planted mums establish extensive root systems over a full growing season and are dramatically more likely to overwinter successfully.
Plant in spring once frost danger has passed — typically from April through May depending on your region. Early spring planting gives the longest season for pinching and root establishment before fall bloom.
Planting Steps
- Prepare the planting area with compost and ensure drainage is adequate
- Dig a hole twice as wide as the root ball and the same depth
- Plant at the same depth as in the container — never bury the crown
- Space 18 to 30 inches apart — generous spacing is essential for air circulation and plant health
- Water thoroughly at planting and maintain consistent moisture for 3 to 4 weeks during establishment
- Apply 2 inches of mulch around plants, keeping mulch away from stems
The Pinching Schedule: The Key to Spectacular Blooms
Pinching is the single most important cultural practice for growing beautiful garden mums. According to Penn State Extension, when plants are six inches tall, pinch about ¾ of an inch from each branch to promote more blooms and bushier plants. When they reach a foot tall, pinch them again. The last pinching should be 100 days before desired bloom time.
Without pinching, a chrysanthemum produces a single central stem with a few large flowers at the top. With regular pinching through spring and early summer, the same plant becomes a compact, densely-branched mound covered in hundreds of smaller blooms. The difference in garden impact is extraordinary.
The Pinching Timeline
- When plants reach 6 inches tall (typically mid-May to early June): pinch the growing tip of every stem to just above the topmost set of leaves. Use your thumb and forefinger — no tools needed. Each pinched stem produces 2 to 3 new branches.
- When new growth reaches 6 inches again (typically late June): pinch every stem tip again. This second pinching dramatically multiplies the number of flowering branches.
- Final pinching (by July 4th in most of the US): this is the deadline — stop all pinching by early July. Pinching after this point removes flower buds that are already forming and delays or eliminates fall bloom. Penn State Extension’s guideline: last pinching should be 100 days before desired bloom time.
What Happens If You Skip Pinching
Unpinched mums grow tall and leggy, produce a small number of blooms on long, floppy stems, and often require staking to prevent them from collapsing under their own weight. The compact, mounding habit that makes garden mums so visually effective is entirely the result of timely pinching — it doesn’t happen naturally without intervention.
Watering and Fertilizing Chrysanthemums
Watering
- Keep soil consistently moist during the growing season — approximately 1 inch of water per week
- Always water at the base of plants — wet foliage is the primary driver of powdery mildew and botrytis, two of the most common mum diseases
- Water in the morning to allow any accidentally wetted foliage to dry completely during the day
- Reduce watering as plants approach their bloom date — some mild stress in late summer can actually intensify flower color
- Mulch around plants to conserve moisture and prevent soil splash onto lower leaves
Fertilizing
According to Penn State Extension Master Gardener, fertilize mums in spring with a balanced fertilizer and again in fall with a highly phosphorus fertilizer (such as 5-10-10) to promote strong root growth before winter.
- Early spring: balanced slow-release fertilizer (10-10-10) as new growth emerges — supports vigorous vegetative growth and stem development
- Through summer (monthly): balanced water-soluble fertilizer every 3 to 4 weeks during active growth
- At first bud formation: switch to low-nitrogen, bloom-boosting fertilizer (5-10-10) to support flower development
- Stop fertilizing after buds form: late-season nitrogen stimulates leafy growth that interferes with flower development and hardening before winter
Common Chrysanthemum Diseases and Problems
According to Penn State Extension’s chrysanthemum disease guide, chrysanthemums are susceptible to a range of fungal and bacterial diseases — the most significant being Botrytis (gray mold), powdery mildew, foliar nematodes, and Pythium root rot. Most of these are preventable through good cultural practices.
Powdery Mildew
White powdery coating on leaves and stems — the most common chrysanthemum disease. Thrives in warm days with cool nights and poor air circulation. Prevention: full sun siting, generous spacing (18 to 30 inches), base-only watering, and choosing resistant varieties. For more on managing this disease organically, see our plant disease guide.
Botrytis (Gray Mold)
Gray fuzzy mold on buds and petals — most common in cool, wet fall conditions when blooms are opening. Remove and dispose of affected flowers immediately. Improve air circulation; avoid overhead watering; water in the morning only.
Aphids
Clusters of small soft-bodied insects on new growth and buds. Penn State Extension confirms chrysanthemums are susceptible to aphids — address with strong water sprays or insecticidal soap. See our complete aphid treatment guide for full management details.
Overwintering Chrysanthemums Successfully
Getting garden mums through winter is where many gardeners struggle — and where spring planting makes the greatest difference. Spring-planted mums with well-developed root systems survive winter at dramatically higher rates than fall-planted ones.
Fall Preparation for Winter
- Do not cut back after frost: leave the dead foliage and stems standing through winter — they trap insulating snow and protect the crown from temperature extremes. Cut back in spring when new growth emerges, not in fall.
- Mulch after the ground begins to freeze: apply 3 to 4 inches of straw or shredded leaves over the crown after the soil starts to freeze. This prevents the freeze-thaw cycles that heave roots out of the ground.
- Do not mulch too early: mulching before the ground freezes creates a warm habitat for mice that will eat the crowns. Wait until after hard freezes begin.
- In Zones 4 and 5: in the coldest climates, additional protection may be needed — place a ring of chicken wire around the plant and fill with straw for extra insulation
Spring Emergence
Remove winter mulch gradually in spring as temperatures moderate. New growth emerges as small red shoots from the base of the plant — often different in appearance from the previous year’s stems. Once new growth is 2 to 3 inches tall, cut back the previous year’s dead stems and begin the pinching cycle again.
Dividing Chrysanthemums for Continued Performance
Penn State Extension recommends dividing chrysanthemums in spring when new growth appears every three to five years to avoid overcrowding and promote maximum flowering. Division simultaneously rejuvenates declining clumps and multiplies your plant stock for free.
How to Divide
- Divide in early spring when new shoots are 1 to 3 inches tall — Penn State Extension specifies this timing for best results
- Dig the entire clump with a garden fork
- Separate outer sections of young, vigorous shoots — these are the divisions to replant
- Discard the old, woody central portion
- Replant divisions at the same depth; water thoroughly; begin the pinching cycle
- Division produces the youngest, most vigorous plants — older central crowns flower less prolifically than outer divisions
Propagating from Stem Cuttings
Penn State Extension also describes propagating mums from cuttings: remove the lower leaves from a 4 to 6 inch healthy stem, dip the cut end into rooting hormone, and insert into moist sterile sand, vermiculite, or sphagnum moss. Cuttings root within 3 to 4 weeks and can be transplanted to the garden after establishment — an excellent way to multiply a prized variety.
Quick-Reference Chrysanthemum Growing Guide
- Plant in spring, not fall — spring planting is the single most important factor in perennial success
- Full sun — 6 hours minimum — shade produces leggy plants and disease problems
- Space 18 to 30 inches apart — air circulation prevents powdery mildew
- Pinch at 6 inches and again at 12 inches — stop by July 4th for fall bloom
- Water at the base only — wet foliage causes mildew and botrytis
- Don’t cut back in fall — leave stems standing for winter crown protection; cut in spring
- Divide every 3 to 5 years — maintains vigor and multiplies plants for free
- Do not rotate more than 3 years in same spot — Penn State Extension recommends rotation to prevent disease and pest buildup
Learning to grow chrysanthemums as true perennials — planted in spring, pinched faithfully through summer, and protected correctly through winter — transforms the most popular fall flower from a temporary decoration into a long-lived garden asset that delivers increasingly spectacular color every autumn. The difference between a handful of grocery-store mums clustered on the porch and a mature, spring-planted mum colony in full fall bloom is one of the most dramatic demonstrations of what good garden management can achieve.
Plant your first garden mums this spring. Follow the pinching schedule religiously through early July. Protect through winter with good mulching. And in two to three seasons, you’ll have the fall garden display you’ve always imagined.
Share your mum photos and pinching questions in the comments — we especially love fall garden before-and-after photos! And for the complete fall garden picture, see our fall garden cleanup guide.
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Maria Walker is a certified horticulturist and gardening specialist with over 15 years of hands-on experience in plant care, garden design, and sustainable growing practices.
She holds a Bachelor’s degree in Horticulture Science and a Master’s degree in Sustainable Agriculture — and has spent her career helping people of all skill levels create beautiful, thriving gardens.
Maria launched Outz News Garden with one simple mission: to make gardening accessible and inspiring for everyone, from first-time planters to seasoned green thumbs.