GROWING GUIDE
Do Mums Tolerate Frost?
Most garden mums tolerate a light frost. A night near 32°F can brown open flowers and still leave a hardy mum's crown alive. A hard freeze, 28°F or lower, ends the flower show. A pot freezes faster than a mum in the ground. Cover or move a pot you want to keep. Do not dig a hardy crown tonight.
The National Weather Service separates frost, a freeze, and a hard freeze. Frost can form on a clear, calm night while the air is still in the mid-30s. A freeze means air at or below 32°F. A hard freeze means about 28°F or lower, long enough that most seasonal growth is killed. University of Minnesota Extension separates florist pot mums from hardy garden mums selected for zones 3 to 9. Those hardy plants have frost tolerance that can keep a display into October. A light frost often browns the open flowers and leaves the crown. Virginia Cooperative Extension's overwintering note covers a protected pot or a cold frame, which is a later job than tonight's cover. Roots in a small pot sit above the ground, so the same 32°F night a border mum shrugs off can freeze that root ball. Move or cover the pot if you want the plant. Once a hard freeze has blackened the flowers, give up the display.
Published · Updated
Cover, move, leave, or give up the flowers?
Frost action: on a light frost, cover or move a pot you want to keep, and leave a hardy mum in the ground. On a hard freeze, give up the flower show, move a pot you want to save, and do not dig a hardy crown. Cutting spent stems, and storing a pot for the winter, are the other guides.
| Tonight | Pot | In the ground | Action |
|---|---|---|---|
| Light frost, air in the mid-30s down to about 32°F, flowers still wanted | Cover the pot, or move it into a shelter. Roots are above the soil. | Leave a hardy garden mum. Cover it only if you want to save open flowers. | Cover or move the pot. Leave the border plant. |
| Hard freeze, about 28°F or lower | Move it in if you want the plant. The flowers are finished. | Do not dig the crown. The display is over. | Give up the flowers. Save a pot. Leave a hardy crown. |
| Flowers already black | Stop trying to save the display. | Cut or leave the stems on the cutback page, not here. | Give up the flowers. Decide the stems later. |
| Florist pot mum from a shop | A cover will not make it a hardy perennial. | Do not plant it tonight and expect it to return. | Give up the outdoor return. Enjoy what is left. |
Look up the night on frost dates for your ZIP. That tool is the median 32°F date, not a promise about tonight’s low. The winter list around this choice is the winter garden. Mulch goes on after the soil has cooled, which is when to mulch, not a frost cloth. What to cut once the tops collapse is perennials after frost.
Keeping a potted mum through the winter, in a protected spot rather than on the porch, is keep potted mums over winter. Use that page for storage. Do not treat this table as the storage method.
Common questions
Do garden mums survive a light frost?+
Often yes. A night near 32°F can brown open flowers and leave a hardy garden mum’s crown alive. Florist pot mums are porch color and are not the same plant.
What is a hard freeze for mums?+
The National Weather Service uses about 28°F or lower. That ends the flower show. It is not a reason to dig a hardy crown the same night.
Should I bring a potted mum inside tonight?+
Move or cover a pot if you want the plant, because the root ball sits above the ground. A mum planted in the ground can usually stay for a light frost.
Where is the overwinter how-to?+
Protected storage, a cold frame, and the spring check are on the keep-potted-mums page. What to cut after the flowers blacken is the perennials-after-frost page. This page does not repeat those steps.
Sources & editorial notes
- National Weather Service: frost and freeze definitions
- National Weather Service: freeze and hard freeze
- University of Minnesota Extension: hardy mums
- Virginia Cooperative Extension: overwintering mums
Tonight’s choice is cover, move, leave, or give up the flowers. Overwinter storage is a different page. Sources checked November 7, 2026. Editorial responsibility.