How to Grow Chrysanthemums
Chrysanthemum × morifolium
The quintessential fall flower — pinch through summer for clouds of color in autumn.
By the Plants by Zone Editorial Team · Reviewed June 1, 2026
About chrysanthemums
Chrysanthemums, or garden mums, are the defining flower of the fall season in American gardens, blooming in every color except blue as days shorten in late summer and autumn. Hardy varieties return reliably as perennials in zones 5–9 when planted early enough in spring to fully establish roots before winter. The classic technique of pinching — removing shoot tips repeatedly through summer — transforms a single lanky plant into a dense, mounded crown loaded with buds.
When to plant and harvest chrysanthemums
Timing is relative to your frost dates. Find your USDA zone for exact dates, or browse the month-by-month calendars.
Start seeds indoors
Start seeds 10–12 weeks before last frost, or take stem cuttings in early spring from overwintered plants
Transplant outdoors
After last frost in spring — the earlier, the better for perennial establishment and bushy growth
Direct sow
Not recommended; most garden mums are grown from named-variety transplants or cuttings
Harvest
Late summer to fall; deadhead spent clusters to extend the display
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How to grow chrysanthemums step by step
- 1
Plant named-variety garden mums in spring, as soon as they appear at garden centers, in rich, well-drained soil in full sun.
- 2
Begin pinching when stems reach 6 in: remove the top inch of each shoot with your fingers or shears. Repeat every 2–3 weeks until mid-July.
- 3
Water consistently at the base and feed with a balanced fertilizer monthly through summer.
- 4
Stop pinching by late July to allow bud formation — plants bloom on short days as summer ends.
- 5
After frost blackens the blooms, cut plants back to 4–6 in and mulch heavily once the ground freezes in cold zones.
- 6
Divide crowded clumps every 2–3 years in early spring, using only the vigorous outer shoots and discarding the woody center.
Common problems growing chrysanthemums
⚠ Plants bloom in summer instead of fall
Artificial lighting at night disrupts the short-day trigger — site mums away from streetlights, porch lights, and lit windows.
⚠ Powdery mildew (white coating on leaves)
Space plants for airflow, water at the base, and remove heavily affected leaves; choose mildew-resistant varieties for humid gardens.
⚠ Aphid clusters on stem tips and buds
Blast off with a strong jet of water, or apply insecticidal soap; avoid excess nitrogen, which promotes the soft new growth aphids prefer.
⚠ Perennial crowns don’t return in spring
Plant in early spring so roots establish before winter; mulch after the ground freezes (not before) to avoid trapping moisture around the crown.
✓ Good companions for chrysanthemums
✗ Keep away from
🧺 Harvesting chrysanthemums
Cut stems in the cool of the morning once one-third of the flowers on a spray are fully open, leaving the rest to continue blooming on the plant. For in-garden displays, deadhead spent clusters at their base to extend the season by two to three weeks. After the display ends, let foliage stand through fall and cut back only when it is fully dormant.
Chrysanthemums: frequently asked questions
When should you plant chrysanthemums?＋
In most regions you start seeds 10–12 weeks before last frost, or take stem cuttings in early spring from overwintered plants, then transplant after last frost in spring — the earlier, the better for perennial establishment and bushy growth. Timing is relative to your last frost, so find your USDA hardiness zone for the exact planting dates where you live.
Will my mums come back next year?＋
Hardy garden mums do return in zones 5–9, but only when planted in spring so the roots fully establish before hard frost. Mums sold in bloom at grocery stores in September rarely have enough root development to overwinter — for reliable perennial performance, plant them in early spring instead of fall.
Why are my chrysanthemums not blooming?＋
Most likely a lighting issue. Mums are short-day plants that need uninterrupted dark nights to trigger bloom. A nearby streetlight, porch light, or lit window can delay or prevent flowering entirely. Move plants or shade them from artificial light each evening.
Sources & review
Written and maintained by the Plants by Zone Editorial Team. Planting times are based on USDA hardiness zones and NOAA frost-date normals, with care guidance drawn from Cooperative Extension sources. Last reviewed June 1, 2026.
USDA Plant Hardiness Zone MapNOAA U.S. climate normalsCooperative Extension
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