Prepping Southern Gardens for a Freeze: When to Use a Frost Cloth

cmichellewoo
3 days ago
3 min read

If you live in the south or in a mild climate, you know the benefits of year-round gardening... and also the panic that sets in when plummeting temps are forecasted. I’m an optimist to a fault and always testing the limits when it comes to growing cut flowers in my garden. When winters are mild, it’s the most wonderful time to garden (no heat stress, little watering, no pests), but when freezing temps threaten to descend - it’s no longer fun and games.

Even if you don’t personally grow hundreds of cool season flowers susceptible to freeze damage, if you’ve got pots or new plantings, you’ll need to take action to protect your garden from time to time.

Knowing when and what to protect can prevent unnecessary damage—without overworking your landscape. Read on to learn more.

What Is a Freeze and Why Does It Matter?

When air temperatures drop to 32°F or below the water inside and around plant cells begins to freeze. This process sets off a chain of events that can cause irreversible damage, depending on the plant’s cold tolerance and how long the freeze lasts.

The National Weather Service classifies freezes by severity and duration, which helps gardeners decide when protection is necessary.

Light Freeze (29–32°F)

A short-duration freeze that primarily affects tender annuals, tropical plants, and new growth. Most established landscape plants tolerate light freezes with little or no damage.

Moderate Freeze (25–28°F)

Can damage or kill tender plants and cause leaf burn or bud damage on cold-sensitive shrubs. Newly planted trees and shrubs are more vulnerable at this stage.

Hard or Severe Freeze (24°F and below)

Extended cold that can damage woody tissue, roots of container plants, and even some plants considered hardy in Zone 8b. Protective measures and plant placement become especially important during these events.

Key takeaway: The length of time temperatures stay below freezing often matters more than how cold it gets.

Which Landscape Plants Need Protection?

Not every plant needs to be covered. Frost protection should be targeted, and depends on plant type, age, and the temperatures you’re facing.

Most likely to benefit from frost cloth:

Tender annuals, Tropicals and veggies
Newly planted trees, shrubs, and perennials (first season in the ground)
Cold-sensitive evergreen shrubs or plants on the border of your zone's recommendation (e.g. jasmine, sago palms, and citrus)
All container-grown plants, since roots freeze faster in pots
Shallow planted bulbs (like Anemones and Ranunculus) - if the ground freezes to their depth of planting, they won’t recover.

Usually not necessary to cover:

Established, zone-appropriate trees and shrubs
Dormant deciduous plants
Hardy perennials that naturally die back in winter

Using Frost Cloth Correctly

Frost cloth (or row cover fabric) traps heat released from the soil overnight. When used properly, it can provide a few degrees of protection—often enough to prevent damage during light frost events.

Best practices:

Install before sunset, while the soil is at its warmest
Ideally, tent the material over a structure, not over the plant directly (garden stakes, cages or hoops)
Extend fabric all the way to the ground and secure edges with landscape fabric
Don’t use plastic or dark covers
Remove coverings as soon as temperatures rise above freezing - don’t leave frost cloths on for an extended time

Additional Tips for Protecting Southern Gardens for a Freeze

Water plants (the roots not the leaves) a day before a freeze - this helps soil retain heat
Mulch around the base of shrubs and perennials
Group containers near buildings or move them into protected areas
Pay attention to microclimates—low spots and windy areas freeze first

The Bottom Line

In southeastern NC, freeze protection is about strategic intervention, not constant covering. Focus on tender plants, new plantings, and containers, and let established, well-chosen landscape plants handle winter as intended.