Knowing the different signs of freeze damage on plants is crucial to helping them survive a freeze. Wilting leaves, discoloration, and even leaves dropping are just some of the tell-tale signs you should be looking out for.
Winter may seem a good time to relax and hang our gardening hats and gloves until next spring. But if you want your lawn and plants to jump back into full vibrancy after the cold spell, you should be on alert for sudden drops in temperature.
Freeze damage symptoms in plants
During extreme freezing conditions, the water inside the plant cells can freeze. As the water turns into ice, it expands and ruptures the cell walls — causing damage to the plant cells, tissues, leaves, stems, and even the entire plant. Depending on how cold it is and the type of plant, freeze damage can be destructive:
- Between 29 and 32 degrees: Light freeze can kill delicate plants.
- Between 25 and 28 degrees: Moderate freeze can be damaging to many plants.
- Colder than 25 degrees: Severe or hard freeze can be heavily destructive to most plants.
Note: Typically, you’ll notice freeze damage on your plants around seven to 10 days after a freeze. But it would depend on the plant type and the severity of the freeze. Sometimes it can be evident almost immediately after a freeze or it could take a few months.
While freeze damage happens at the microscopic level, you’ll be able to see the effect on your plant leaves and tree barks. The most common signs of freeze damage on plants are:
1. Water-soaked or wilting leaves
As the leaves of freeze-damaged plants start to lose their rigidness, they begin to droop or wilt. Oftentimes, the water-soaked leaves cause the plant tissues to turn black within a few hours or days.
My tip: To avoid freeze damage on plants, you can bring your plants inside, if possible.
2. Discolored or blackened leaves
If you can’t bring your plants indoors, another threat looms underneath. The ground can freeze and significantly prevent your plants from absorbing water. With limited or no water, the leaves will discolor and turn brown. Keep in mind that even your hardy evergreens are vulnerable to this type of damage.
According to Nancy Dourbrava, former horticulture information specialist at the Home and Garden Information Center at Clemson University, low-temperature damage can lead to the tips of narrow-leaved evergreens like junipers to turn uniformly brown.
Even if the ground doesn’t freeze, low temperatures can still cause necrotic or black spots to appear on leaves, petals, and flowers because of cell walls breaking down.
My tip: You can use a breathable cover like fleece, blanket, sheet, towel, or tarp to keep your plants warm during a freeze. But don’t let them get soaked or overheated.
3. Split bark on trees
If you have woody plants in your yard, look out for frost cracks. Affecting both young and old trees, these are deep, narrow, and long cracks running down the trunk. They’re mostly caused by contraction due to temperature changes.
The tree trunk naturally expands as the sun warms it up. But during winter, the temperature drastically drops after the sun sets, causing the trunk to contract. With the outer trunk contracting faster than the inner tissues, it starts to crack.
My tip: Wrap your tree trunks with burlap to prevent cracking during winter. Then, you can remove the wrap once the temperature warms up after the last frost date.
4. Distorted leaves and soft tissues
Another sign of freeze damage is when leaves get distorted out of their natural shape. As the water in the leaves freezes and the cells rupture, it disrupts the structure of these leaves — causing them to curl or twist, especially at the edges.
Depending on how severe the exposure is, these leaves can even turn black and their tissues can turn mushy and soft.
5. Leaves dropping
Severe freeze damage on plants, particularly the broken-down cell structure on the leaves, can lead to leaves falling off the plant. This symptom is often preceded by discoloration and distorted leaves.
When the leaves of your plants fall off, it’s a clear indicator that your plant has already spent too much time in the freezing weather. While there’s still a chance to save your plant, the effort will be far greater.
My tip: Don’t neglect your turfgrass. Even if you live in a warm region, there’s still a chance that freeze can damage your lawn. So, it wouldn’t hurt to follow a winter lawn care routine.
FAQ about freeze damage on plants
Should I cut off frost-damaged leaves?
No. While it’s tempting to cut off frost-damaged leaves immediately, you should leave this dead material untouched until spring. Removing it during winter exposes the remaining part to frost, so it’s best to just leave it as insulation. Additionally, this can help you assess the damage better and prevent you from cutting off what is actually a living tissue.
Can plants recover from freeze damage?
You can still save plants after a freeze, but it would depend on the plant type and the severity of the damage. Plants that survive but are severely damaged will need an expert’s help to jump back on their roots. To ensure they survive through a freeze, you must set up preventive measures before the freeze.
How can I tell if my frost-damaged potted plant is beyond saving?
Inspect the roots of the plant by gently wiggling it out of its pot. If the roots are mushy, it’s a clear sign the plant is dead. However, even if the roots have already turned black, they can still be saved as long as they have not turned rotten.
Protect your plants from freeze damage
The symptoms listed here can help you determine which plants in your garden will need extra help when spring comes. However, the recovery process can take a long time. So, don’t wait for your plants to get damaged before taking action. It would be better to have a local lawn care pro help you protect your plants from a freeze.
Sources:
- https://www.nrcs.usda.gov/wps/portal/wcc/home/climateSupport/wetlandsClimateTables/growingSeasonDatesLength/
- https://www.tn.gov/protecttnforests/forest-health/other-threats/frost-and-freezing.html
- https://hgic.clemson.edu/factsheet/cold-damage/
- https://www.canr.msu.edu/news/frost_cracks_in_trees
- https://hyg.ipm.illinois.edu/article.php?id=885
Main Photo Credit: Juhku | Adobe Stock Free | License
