What Does a Late Frost Do to New Plant Growth?

It never fails, a late frost in spring, gardeners get excited when shrubs and trees begin pushing out fresh green leaves. New growth makes it feel like winter is finally over. Then the forecast suddenly calls for a late frost.

This is a common problem here in Georgia. Warm temperatures can encourage plants to break dormancy early, only for a cold night to arrive after tender leaves and flower buds have already opened.

Quick Answer: What Does a Late Frost Do to New Plant Growth? A late frost can damage tender new leaves, shoots, flower buds, and blooms after plants have already started growing in spring. Blackened leaves and wilted growth can look severe, but established shrubs and trees often recover from healthy stems and roots. Wait several days before pruning, check stems for green tissue, and avoid fertilizing heavily until the plant begins actively growing again.

By the next morning, healthy-looking plants may have blackened leaves, wilted stems, or damaged flower buds. It can look serious, but most established shrubs and trees recover better than many homeowners expect.

According to the University of Georgia Extension’s guide to spring freezes and landscape plants, tender new leaves, flower buds, and blooms are especially vulnerable when temperatures suddenly fall below freezing.

Here is what late frosts do to new growth, which plants are most vulnerable, and what you should do before reaching for the pruning shears.

Why New Growth Is So Vulnerable

During winter, dormant plants are naturally prepared for cold temperatures. Their buds remain closed, and their living tissue is protected.

Once those buds open, the situation changes.

Tender new leaves and shoots contain a high amount of water. When temperatures fall below freezing, ice crystals can form inside the plant tissue and damage the cells.

That damage may become visible within hours.

New growth is especially vulnerable because it has not yet developed the tougher tissue found on mature leaves and stems.

Frost Damage Versus Freeze Damage

Although people often use the words frost and freeze interchangeably, they are not exactly the same.

A light frost usually forms when temperatures near the ground fall to around 32 degrees. It may damage exposed leaves and flower buds while leaving the stems unharmed.

A harder freeze can cause more serious injury, especially when temperatures remain below freezing for several hours.

A light frost may only damage the outermost leaves. A hard freeze may injure:

• Tender stems
• Flower buds
• Newly opened leaves
• Young annuals
• Newly planted shrubs
• Container plants

The length of time temperatures remain below freezing is often just as important as the lowest temperature reached.

Signs of Frost Damage

Frost damage can look different depending on the plant and the severity of the cold.

Common signs include:

• Black or brown leaf edges
• Wilted or limp new leaves
• Soft stems that collapse
• Brown or black flower buds
• Water-soaked-looking leaves
• Curled or shriveled new growth
• New shoots that stop growing

Some leaves may not show damage immediately. They may look normal in the morning and begin turning brown later in the day.

Hydrangeas Often Show Damage First

Bigleaf hydrangeas are especially vulnerable to late frosts because they often begin leafing out early.

A sudden freeze can blacken the new leaves almost overnight. It may also damage flower buds that formed on the previous year’s stems.

The plant itself may survive and grow normally, but it may produce fewer blooms that season.

This is especially important with old-wood hydrangeas, including many bigleaf and oakleaf varieties. Their flower buds may already be present before spring arrives.

Panicle hydrangeas and smooth hydrangeas usually recover more easily because they bloom on new growth produced during the current season.

Late frost can be particularly frustrating for hydrangea growers because the plant may still produce healthy leaves even when its flower buds have been damaged. Learn more in our guide, Why Is My Hydrangea Not Blooming? 7 Hidden Causes.

Our Experience With Late Frost Damage

At Bobby & Lynn’s Plant Farm, we have seen late frosts damage tender new leaves on hydrangeas and other shrubs many times.

The plants can look terrible the morning after a freeze. Leaves may turn black, hang limp, or look completely lifeless.

We have learned not to panic and not to prune too quickly.

In many cases, the stems remain healthy even though the first set of leaves is damaged. Once warmer temperatures return, new buds often begin growing farther down the stem.

Within a few weeks, many plants look much better than they did immediately after the frost.

The biggest lesson we have learned is that patience is often the best treatment.

Do Not Rush to Prune

One of the most common mistakes gardeners make is cutting off damaged growth immediately.

Wait several days before pruning.

The outer leaves may be dead while the stems underneath remain alive. If you prune too quickly, you may remove healthy buds that would have produced new growth.

Waiting also gives you time to see where the actual damage ends.

When you do prune, cut only the parts that remain clearly dead after warmer weather returns.

How to Check Whether a Stem Is Still Alive

A simple scratch test can help determine whether a branch survived.

Use your fingernail or the edge of a clean pruning tool to lightly scratch the outer bark.

If the tissue underneath is green, the stem is still alive.

If it is brown and dry, move slightly farther down the branch and test again.

Do not remove the entire branch unless you are sure it is dead.

Should You Remove Damaged Leaves?

You do not have to remove every damaged leaf immediately.

Brown or black leaves will not turn green again, but they do not always need to be pulled off right away.

Allow the plant time to begin producing new growth. Once healthy leaves appear and the risk of another frost has passed, you can gently remove damaged leaves if they do not fall naturally.

Avoid stripping too many leaves from a stressed plant at once.

Should You Fertilize After Frost Damage?

Usually, no.

Applying heavy fertilizer immediately after frost damage can encourage another flush of tender growth. If another cold night arrives, that new growth may be damaged again.

Instead:

• Water only when the soil begins to dry.
• Avoid over watering.
• Allow the plant time to recover naturally.
• Resume normal fertilizing once temperatures remain consistently warm.

Fertilizer cannot repair damaged leaves or flower buds.

Can Plants Recover From a Late Frost?

Most established shrubs and trees can recover from a single late frost.

Their roots and older stems contain stored energy that allows them to produce another set of leaves.

Recovery may take several days or several weeks depending on:

• The type of plant
• The severity of the freeze
• How long temperatures remained low
• Whether the plant was newly planted
• Whether the roots were already stressed
• Whether additional freezes occur

Young plants and newly planted shrubs may recover more slowly because they have smaller root systems.

Will the Plant Still Bloom?

That depends on how the plant produces its flower buds.

Plants that bloom on new wood often recover and flower normally later in the season.

Plants that bloom on old wood may lose some or all of their flowers if the frost damages the buds.

For example, a bigleaf hydrangea may grow plenty of healthy leaves after a freeze but produce very few flowers that year.

This does not mean the plant is dying. It simply means the flower buds were damaged.

How to Protect Plants Before a Late Frost

If a frost or freeze is forecast, you may be able to reduce damage by covering vulnerable plants.

Use:

• Frost cloth
• Old bed sheets
• Lightweight blankets
• Large cardboard boxes for small plants
• Upside-down containers for young plants

Make sure the cover reaches the ground so it can trap some of the warmth rising from the soil.

Remove the covering the next morning once temperatures rise.

Avoid allowing plastic to rest directly against the leaves. Plastic can transfer cold to the plant tissue and may cause damage where it touches.

Should You Water Before a Frost?

If the soil is dry, watering before a frost can help.

Moist soil holds heat better than completely dry soil. Water the ground earlier in the day so the moisture has time to soak in before temperatures fall.

Do not soak already-wet soil, especially in heavy Georgia clay.

over watering can create additional root stress and drainage problems.

Do Container Plants Need Extra Protection?

Yes.

Container plants are more vulnerable because their roots are exposed to colder air on all sides.

Move smaller containers into:

• A garage
• A covered porch
• A shed
• An enclosed patio
• A sheltered area beside the house

Large containers that cannot be moved can be wrapped or grouped together in a protected location.

Remember to return plants to proper light conditions after the cold weather passes.

When Is Frost Damage Permanent?

Frost-damaged leaves will not repair themselves.

However, leaf damage alone is usually temporary because the plant can produce new leaves.

Damage becomes more serious when:

• The main stems are killed
• Flower buds are destroyed
• A newly planted shrub has severe root stress
• The plant experiences repeated freezes
• The plant was already unhealthy
• Temperatures remain extremely low for a long period

Even when flowers are lost for one season, the plant may still recover fully and bloom again the following year.

Plants Most Vulnerable to Late Frost

Plants that leaf out or flower early are often the first to show damage.

These may include:

• Bigleaf hydrangeas
• Japanese maples
• Azaleas
• Gardenias
• Crape myrtles with early growth
• Fruit trees
• Roses
• Newly planted shrubs
• Tender annuals
• Container plants

Plants in low areas of the yard may also experience more damage because cold air settles in lower spots.

When Is It Safe to Prune?

Wait until the risk of additional frost has passed and the plant has had time to show new growth.

In Georgia, the timing can vary from year to year. A warm stretch in late winter does not always mean freezing weather is finished.

Once you see healthy new buds opening, remove only the stems that remain brown, dry, and lifeless.

Pruning too early may make the damage worse.

Frequently Asked Questions

Will frost-damaged leaves turn green again?

No. Once plant tissue has been damaged by freezing temperatures, it will not return to normal. However, the plant may produce healthy replacement leaves.

Should I cut off black leaves immediately?

Usually not. Wait several days so you can see which stems and buds remain alive.

Can a late frost kill a hydrangea?

A single late frost rarely kills an established hydrangea. It may damage leaves and flower buds, but the root system and stems often survive.

Why does my hydrangea have leaves but no flowers after a frost?

The plant may have survived while the flower buds were damaged. This commonly happens with hydrangeas that bloom on old wood.

Should I fertilize a frost-damaged plant?

Wait until the plant begins actively recovering and the danger of additional frost has passed.

Does watering after a frost help?

Watering may help if the soil is dry, but avoid keeping the roots overly wet.

The Bottom Line

Late frosts can make healthy plants look much worse than they really are.

Black leaves, wilted shoots, and damaged flower buds do not automatically mean a plant is dead.

Give the plant time to recover before pruning, fertilizing, or replacing it. Check the stems for green tissue and watch for new buds farther down the branch.

At Bobby & Lynn’s Plant Farm in Dallas, Georgia, we have seen many shrubs recover from unexpected spring freezes. In most cases, a little patience and normal care are all the plant needs.

The leaves may be damaged, and the blooms may be reduced for the season, but established plants are often much tougher than they look.