Should I Cover My Mums From Frost?

When It Makes Sense

• Good fit: You expect a brief, light frost — usually around 28–32°F for only a few hours — and your mums still have unopened buds or fresh flowers you want to keep. A breathable cover such as an old sheet, frost cloth, or burlap can trap enough ground warmth to prevent blossom damage and keep the display going a little longer.
• Good fit: The plants are garden (perennial) mums you hope to overwinter, and the frost is arriving before the ground has frozen. Covering for a night or two can reduce stress on foliage and stems, especially if they are in an exposed bed or slightly outside their recommended hardiness zone. It is most helpful when combined with a 2–3 inch layer of mulch at the base to insulate roots.

When You Should Avoid It

• Warning sign: A hard freeze is forecast — temperatures in the mid-20s°F or lower for several hours, or a prolonged cold snap. A temporary cover cannot hold back that much cold, and leaving it in place for days can trap moisture, block light, and encourage rot or fungal problems. In that case, it is usually better to focus on root survival and accept that the flowers are done for the season.
• Warning sign: You are using plastic sheeting that will touch the foliage, or you plan to drape a heavy wet blanket directly over the plant. Plastic conducts cold to leaves where it contacts them and can cause more damage than no cover at all. Wet fabric can also weigh down stems and break them. Any cover should be supported by stakes or a frame so it does not rest on the plant, and it should be removed during the day.

Pros and Cons

Pros

• Protects blooms and extends color. Mums are often purchased for their fall display, and a light frost can turn open flowers brown or wilt buds. A cover can buy a few extra days or weeks of color, which is worthwhile if you are using them for a seasonal event, sale, or curb appeal.
• Reduces cold stress on stems and buds. Even if the flowers eventually fade, protecting the upper growth from repeated light frosts can leave the plant in better condition to store energy and, for perennial varieties, survive the winter.

Cons

• Labor and timing. Frost protection is not a set-it-and-forget-it task. You must put covers on in late afternoon or evening, secure them against wind, and remove them the next morning once temperatures rise. For multiple plants or large beds, this can become a nightly chore during a frost period.
• Risk of physical damage and disease. Covers can crush delicate stems, especially when wet. They also reduce air circulation and trap dew, creating conditions for gray mold, mildew, and other fungal issues if left on too long. A poorly anchored cover can blow off and leave plants exposed at the coldest hour.

Decision Checklist

• What does the forecast actually say? Check the predicted low temperature, how long it will stay at or below freezing, wind speed, and whether precipitation is expected. A short dip to 32°F is very different from a six-hour hard freeze at 24°F.
• What stage are the mums in? If they are still loaded with buds or fresh flowers, covering is more rewarding. If most blooms are spent and you mainly want the plant to survive winter, mulch and root protection matter more than covering the tops.
• Do you have the right materials and time? A breathable fabric, stakes or a frame to keep it off the foliage, and a schedule to remove it each morning are essential. If you cannot check the cover daily, the risks may outweigh the benefits.

Alternatives to Consider

If covering seems impractical, you have other options depending on your goal. For potted mums, simply move them to an unheated garage, shed, or covered porch on frosty nights; this is often the easiest way to protect both flowers and roots. For in-ground plants, apply 2–3 inches of loose mulch around the base after the first hard freeze to insulate roots without smothering the crown. Planting garden mums in a sheltered spot near a wall, fence, or large shrub can raise nighttime temperatures by a few degrees through microclimate effects. Choosing varieties rated for your USDA hardiness zone also reduces the need for intervention. Finally, many people treat florist or decorative mums as annuals, enjoying the display until frost and replacing them next year rather than trying to overwinter them.

Final Recommendation

Cover your mums from frost when the forecast calls for a brief light freeze and the plants still have buds or blooms worth saving. Use a breathable fabric supported above the foliage, remove it promptly in the morning, and pair it with mulch for garden mums you want to keep. Skip the cover when a hard, prolonged freeze is expected, when you cannot remove it daily, or when only plastic or heavy wet materials are available. For region-specific advice on mum hardiness, overwintering, and local frost dates, consult your nearest university extension office or a qualified horticulturist.