When to Plant Mums: Spring vs Fall, and Why Fall Mums Die

Garden mums, Chrysanthemum × morifolium, are daisy-family perennials bred from several Chinese species (NC State). They are short-day plants: Virginia Tech says they set flower buds as the days shorten in late summer, which is why they bloom in September and October when little else does. The same timing explains the most common complaint about them. A mum bought in full bloom in fall is spending its energy on flowers, not roots, so it often fails to survive its first winter in the ground (Virginia Tech).

When to plant mums

Virginia Tech says mums can be transplanted any time from early spring until they bloom, but the best time is before flower buds set in late summer. Garden centers mostly sell mums in late summer and fall, so for perennial plants look for them in spring (our reading). Use our planting calendar to find your last spring frost.

Can you plant mums in the fall?

Yes, with lower odds. Virginia Tech's advice for fall planting:

• Plant early. Late August or early September gives roots time to grow before the ground freezes. Short fall days push mums to flower rather than root (Virginia Tech).
• Buy small and in bud. Virginia Tech suggests smaller plants, such as 1-quart pots, that are not yet flowering.
• Pick a sunny spot with six or more hours of direct sun (Virginia Tech).
• Keep watering until the first hard frost, then taper off (Virginia Tech). Missouri says mums have shallow roots, which makes them prone to frost heaving in winter.

If it is already late October, Virginia Tech offers an alternative: keep the mum in its pot and overwinter it in a cold frame, or in an unheated basement or insulated garage where it will not freeze. Arkansas notes that most people simply enjoy fall mums in containers for the 3 to 4 weeks they bloom. Our reading is that a mum bought in bloom this month is a good buy for porch color, and a bonus if it comes back.

How to plant mums

Pinching, feeding and watering

• Pinch for bushy plants. Virginia Tech pinches off about 1/2 inch of each tip when plants are 6 to 8 inches tall, then again when the side branches are 8 to 10 inches long. Clemson removes 1/2 to 1 inch of new growth about every four weeks from 6 inches tall.
• Know when to stop. Virginia Tech stops by mid-July, because later pinching can delay flowers past the first frost. Clemson pinches until early July in the upper Piedmont and mountains and early August at the coast; NC State makes its last cut around mid-August, and Arkansas stops in August.
• Feed lightly and often. Clemson calls mums heavy feeders and uses a weekly soluble fertilizer; Virginia Tech uses a weak 5-10-5 solution every 7 to 10 days until the flowers show color.
• Water deeply. Virginia Tech soaks the ground every week or two in dry spells and keeps the leaves dry at night to limit leaf disease. Clemson says mums need the most water when they bloom.
• Stake tall types. Virginia Tech stakes tall-growing types.

Getting mums through winter

• Mulch over the crown. Virginia Tech adds 3 to 4 inches of light, airy mulch such as pine needles, loose shredded bark, clean straw (not hay) or evergreen branches. Missouri says mums' shallow roots are prone to frost heaving, which a loose mulch helps prevent.
• Old stems: the sources differ. Virginia Tech leaves the stems and foliage on until after the first hard frost for insulation. Arkansas cuts the stems back once the first freeze comes, and Missouri cuts the tops back after the leaves turn brown, both followed by mulch.
• Protect even spring-planted mums. Missouri says to assume a new mum needs winter protection its first year, whether it was planted in spring or fall.
• Uncover in spring. Pull the mulch back in early to mid-April once severe cold has passed (Virginia Tech, Missouri).
• Drainage matters. Virginia Tech stresses a well-drained site for overwintering.

Pests and problems

Clemson lists aphids, thrips and spider mites, plus powdery mildew, botrytis blight, aster yellows, leaf spots, viruses and foliar nematodes; NC State adds lace bugs. NC State tags garden mums as deer and rabbit resistant. It also lists them as mildly poisonous and a problem for cats, dogs and horses, and says the foliage can cause mild skin rashes in sensitive people, so wear gloves when pinching if you react (our reading).

Mums around the vegetable garden

NC State notes that mums offer late-season nectar for pollinators. A few plants at the sunny end of a bed keep color going after summer crops finish. For other fall-blooming flowers, see when to plant asters; NC State suggests aromatic aster as a native substitute for fall mums. For cool-season color that goes in at the same time as fall mums, see when to plant pansies. Shasta daisies are a summer-blooming daisy for the same sunny, well-drained spot, and what to plant in fall covers the vegetables that go in now.

Frequently asked questions

When is the best time to plant mums?

In spring, after frost danger has passed, if you want them to come back; Virginia Tech plants in May or early June. For fall planting, Virginia Tech says late August or early September.

Can I plant mums in October?

You can, but expect lower survival. Virginia Tech says the later mums are planted, the lower the survival rate. Treat them as seasonal color, or keep them potted in an unheated garage or cold frame over winter.

Do mums come back every year?

Garden mums are perennials in Zones 5 to 9, but many fall-bought mums don't return. Arkansas says most are bred for color, not hardiness, and Virginia Tech says even survivors are usually best in their first year.

Should I cut back mums in the fall?

The sources differ. Virginia Tech leaves the stems until after the first hard frost for insulation; Arkansas and Missouri cut them back after frost. Either way, mulch the crown with 3 to 4 inches of loose mulch.

When should I stop pinching mums?

By mid-July, says Virginia Tech, or later pinching can delay flowers past frost. In warmer areas Clemson pinches until early August near the coast, and NC State makes its last cut around mid-August.

What is the difference between garden mums and florist mums?

Both are Chrysanthemum x morifolium, but florist mums are not bred for hardiness and won't survive freezing (Virginia Tech). Garden mums are the ones to plant outdoors (UF/IFAS).