Chrysanthemum Care: Planting, Pinching and Fall Blooms

To keep garden mums coming back, plant them in spring, give them full sun and well-drained soil, and pinch them through summer. NC State describes hardy garden mums as herbaceous perennials in the daisy family that flower in autumn, and Penn State says they bloom well after other garden plants have stopped for the season. Illinois Extension says that if you plant them in fall, as most people do, they may struggle to survive winter.

Sun

Full sun, 5–6+ hours

Lifecycle

Perennial

Origin

Asia

Container friendly

Yes

Soil

Fertile, loamy or sandy, well drained

Spacing

18–30 in apart

Size

1–3 ft tall, 1–2 ft wide

Bloom time

Autumn, as days shorten

Pets

Toxic to dogs, cats, horses (ASPCA)

When to plant

Penn State says early spring is ideal, ideally after all danger of freezing has passed, and that mums can be planted almost any time if the roots can establish at least six weeks before frost. Illinois Extension is more cautious: most planting guides recommend spring planting if you want the plants to remain in your garden as perennials, and fall-planted mums may struggle to survive winter. Potted mums bought in fall are best treated as seasonal color.

Sun, soil and spacing

Penn State says mums need full sun, at least five to six hours daily, with full early-morning sun, and Illinois Extension says more than 6 hours. For soil, Penn State and Illinois both say well-prepared, fertile, well-drained loamy or sandy soil. Illinois says not to plant them in areas with poor drainage or occasional standing water. Space plants 18 to 30 inches apart (Penn State). They form erect mounds 1 to 3 feet tall and 1 to 2 feet wide (NC State).

Water and feeding

Penn State says mums want plenty of moisture while growing, with good air circulation and drainage. Aphids and mildew are the usual troubles, so keeping the foliage dry is a priority. For feeding, Penn State says to give light, frequent feedings of a balanced fertilizer during growth and to stop once flower buds form.

Pinching and deadheading

Pinching is what makes a mum bushy. Penn State says to pinch about 3/4 inch from each branch when plants are 6 inches tall, and again at a foot tall. The last pinch should be 100 days before the bloom you want (Penn State), although NC State says the last cut is around mid-August. Remove faded blooms regularly to prolong flowering (Penn State).

Why mums bloom in fall

Illinois Extension says mums are short-day plants that flower when days are under about 12 hours, so the shortening days of fall are their cue. Illinois also says early- and late-season types are sold, and Penn State says hundreds of varieties differ in height, color, flower size and bloom time. For the rest of the fall garden, see our bloom calendar.

Winter care

Sources differ here. Illinois Extension research favors leaving old growth standing with 4 inches of mulch. Penn State says in one article to cut back after a hard frost and mulch lightly, and in another to not cut back marginally hardy perennials like garden mums. Illinois and Penn State both say hardiness varies, and in colder winters plants may be killed.

Chrysanthemums in containers

NC State says mums work well in containers near a patio or in window boxes.

Common chrysanthemum problems

Pets

The ASPCA lists chrysanthemum as toxic to dogs, cats and horses, and gives vomiting, diarrhea, hypersalivation, incoordination and dermatitis as clinical signs.

Grow these next

Mums are the fall counterpart to tulips, which are planted in fall for spring bloom. See also calla lily for summer color, and our fall bulb planting guide for the other fall jobs.