Do plants hibernate in winter?

Plants do not hibernate the way animals do. They go dormant, which means they slow their metabolism, stop growing, and raise the solute concentration inside their cells to lower the freezing point of the water they hold. Dormancy is a survival state, not sleep, and it is triggered by shortening days and falling temperatures.

What happens to plants in the winter?

Deciduous trees and shrubs pull sugars and chlorophyll back from their leaves, drop the leaves, and halt new growth. Herbaceous perennials die back to their roots and wait underground. Evergreens keep their foliage but slow nearly everything down, which is why growth stalls until spring warmth returns.

Do plants die in the winter?

Dormant plants die when the night drops past the lowest temperature their cold hardiness can handle, because ice then forms inside their cells and ruptures the walls. A plant rated for your zone usually survives an average winter, but an unusually cold night, or a wet one that rots dormant roots, can still kill it. Whether your plant lives depends on the low your yard reached, which can run colder than the regional forecast.

How do plants survive the cold?

Hardy plants survive by concentrating sugars and other solutes in their cells, which acts like antifreeze and lowers the temperature at which the water inside them freezes. They also move water out of cells into gaps between them, so ice that forms does less damage. This cold hardiness builds as the plant enters dormancy and fades as it wakes in spring.

October 9, 2026

Do plants hibernate, or do they go dormant?

Plants do not hibernate the way a bear does. They go dormant, slowing their metabolism and halting growth to ride out winter. Whether dormancy saves a plant or kills it depends on how cold your yard gets, which can sit well below the number on the regional forecast.

What dormancy does inside the plant

As days shorten and temperatures fall, a plant reads the season and shifts gears. A deciduous tree pulls chlorophyll and sugars back out of its leaves, drops them, and stops pushing new growth. A herbaceous perennial dies back to its roots and waits underground. An evergreen keeps its foliage but slows nearly every process down.

Inside the cells, the plant concentrates sugars and other solutes. That raises the solute level the way salt lowers the freezing point of a road, so the water held in the cells freezes at a colder temperature than plain water would. Many hardy plants also move water out of their cells into the spaces between them, where ice can form without rupturing cell walls. This built-up tolerance is what gardeners call cold hardiness.

What a hardiness rating is telling you

A plant's hardiness zone describes the coldest average winter low it survives while dormant. Our garden sits in zone 7a. The coldest night we recorded this year dropped to 3°F, on the ninth of January. A plant rated for 7a is built to handle a low near 0°F to 5°F in full dormancy, so it rides out a night like that one. Push a 7a plant to a zone-6 night and its antifreeze runs out.

The rating works because dormancy and hardiness build together. A plant hit by a hard freeze in January, when it is fully dormant, handles far more cold than the same plant hit in October before it has hardened off. This is why an early fall frost or a late spring frost does more damage than a deep midwinter one. The plant is caught with tender tissue and no antifreeze loaded yet.

When dormancy fails and the plant dies

Dormancy fails when the night drops past the point the plant's cells can defend. Water inside the cells freezes, the ice expands, and it tears the cell walls. The plant thaws to mush in those tissues. Roots can also die a slower way, by sitting in cold, waterlogged soil that starves them of oxygen and invites rot while the plant cannot repair itself.

So two things decide survival. One is the plant's hardiness, which you read off the label. The other is the lowest temperature your ground reached, which no label knows. A hardiness rating tells you cold tolerance. It cannot tell you whether your specific bed hit that low on a given night.

Why your yard's real low is the number that counts

The forecast low comes from a regional model or a distant airport reading. Your beds can run colder, because cold air is denser and drains downhill to settle in low spots on still nights, and because open sky pulls heat off the ground faster where nothing shelters it. In our own garden the station learns a −7°F offset against the forecast. A night the forecast put at 10°F dropped to 3°F in our beds. For a plant rated to about 5°F, that gap is the difference between waking up in spring and not.

That same offset shifts the frost dates we plan around. Our published dates are a last frost of the 28th of April and a first frost of the 22nd of October. After the learned offset, our effective dates tighten to the 20th of May and the 30th of September. A plant chosen for the published season would be caught out at both ends here.

If you garden free, you set this offset by hand in Settings, under the garden's microclimate offset. A connected station on Pro learns it for you after about 14 days of overlapping outdoor readings, comparing your station's nightly low with the modelled low. Until then it uses the manual number you entered.

Before you trust any plant's zone rating, find out what your own ground does. Run your beds through the microclimate checker to see how far nearby stations' lows sit from the area model, then match plants to that colder number using plants that survive winter outside by your real low and winter-hardy plants for your yard's real low.

Common questions.

Do plants hibernate in winter?: Plants do not hibernate the way animals do. They go dormant, which means they slow their metabolism, stop growing, and raise the solute concentration inside their cells to lower the freezing point of the water they hold. Dormancy is a survival state, not sleep, and it is triggered by shortening days and falling temperatures.
What happens to plants in the winter?: Deciduous trees and shrubs pull sugars and chlorophyll back from their leaves, drop the leaves, and halt new growth. Herbaceous perennials die back to their roots and wait underground. Evergreens keep their foliage but slow nearly everything down, which is why growth stalls until spring warmth returns.
Do plants die in the winter?: Dormant plants die when the night drops past the lowest temperature their cold hardiness can handle, because ice then forms inside their cells and ruptures the walls. A plant rated for your zone usually survives an average winter, but an unusually cold night, or a wet one that rots dormant roots, can still kill it. Whether your plant lives depends on the low your yard reached, which can run colder than the regional forecast.
How do plants survive the cold?: Hardy plants survive by concentrating sugars and other solutes in their cells, which acts like antifreeze and lowers the temperature at which the water inside them freezes. They also move water out of cells into gaps between them, so ice that forms does less damage. This cold hardiness builds as the plant enters dormancy and fades as it wakes in spring.

Related guides

Free planting tools

When to plant shows the last date to sow each crop before your fall frost.
Microclimate checker shows how much colder or warmer gardens near you ran than the forecast low.
GDD estimator adds up a typical season's heat and shows which crops can ripen where you are.