Watering and seasonsBC-06

Bonsai Winter Care: Where to Keep 13 Species, Why Frost Comes First, Cold Frame Alternatives, Winter Watering and Checking for Dead Trees

Published 2026-10-22 · By Bonsai Calendar editors

Your guide: KouKnows everything. Sometimes writes things that are wrong. Sorry in advance.Bonsai Calendar editors · Checked against bonsai writers, nurseries and garden product makers: 2026-10-22

Kou

For bonsai winter care, let trees take 2 to 3 frosts, then move each species into a cold frame, under the bench or under the eaves. Protect cold-sensitive needle juniper and banyan fig early.

In this article (15 sections)

In short: where should you keep bonsai in winter?
Why let bonsai take frost before moving them in for winter?
How do a cold frame, under the bench, under the eaves and indoors differ for bonsai winter care?3
Which bonsai are weak to cold in winter?
How do you prevent dry wind and frozen pots in bonsai winter care?
How do you water bonsai in winter?
What do you do for bonsai in winter?1
1. Jump to this section
2. Can you prune or wire in winter?
What if you have no winter protection or cold frame?
How can you tell if a bonsai has died in winter?
When does bonsai winter care end?
How should you change bonsai winter care in cold or warm areas?
What terms come up when talking about bonsai winter care?
What else should you know alongside bonsai winter care?
What are common questions about bonsai winter care?5
Sources

In short: where should you keep bonsai in winter?

For bonsai winter care, let trees take 2 to 3 frosts, then move them into a cold frame, under the bench or under the eaves to suit the species. Protect needle juniper early, and bring the banyan fig indoors.

As a general rule, bonsai are outdoor trees, so they spend the winter outside too. If you bring them into a heated room because it is cold, they bud poorly the next year.

The hard part is deciding how much protection to give. Even among bonsai, some trees can stay on the bench while others are better off in a cold frame.

Autumn is the time to decide where each tree goes and start preparing. Once frost begins, move the pots one by one using the table below.

What this article covers:

Winter spots for 13 species
Why trees take frost before going in, and the signs to watch
How a cold frame, under the bench, under the eaves and indoors differ
Trees weak to cold, and winter watering
Winter jobs, and what to use if you have no cold frame
How to tell whether a tree has died

Bonsai care calendar by species
Species	Type	Winter spot
Japanese black pine	Conifer	Outdoors on the bench, out of drying wind; small or weak trees under eaves or in a cold frame
Japanese white pine	Conifer	Cold frame (mid-December to February)
Shimpaku juniper	Conifer	Under the bench or in a cold frame after 2-3 frosts
Needle juniper	Conifer	Cold frame, moved in early (weak to cold and dry air)
Japanese maple	Deciduous	Cold frame after 2-3 frosts
Trident maple	Deciduous	Under the bench or in a cold frame after 2-3 frosts (mid-December to March)
Japanese zelkova	Deciduous	Under the bench or in a cold frame after 2-3 frosts
Japanese apricot (ume)	Flowering	Cold frame
Flowering cherry (e.g. Asahiyama)	Flowering	Under the bench or in a cold frame after 2-3 frosts
Satsuki azalea	Flowering	Under the eaves (December to March)
Chojubai (dwarf flowering quince)	Flowering	Cold frame
Crabapple (hime-ringo)	Fruiting	Cold frame, out of frost and dry winter wind
Banyan fig (gajumaru)	Indoor	Indoors (5°C or above)

Source (13)

The table above shows winter spots for 13 species. Even among conifers, black pine stays on the bench while white pine and needle juniper go into a cold frame.

Spot	What it is	Example species in the table	Watch out for
On the bench	On top of an outdoor bench	Black pine	Keep out of strong, dry wind
Under the bench	The space under the bench, enclosed with sheeting	Shimpaku, trident maple, zelkova, cherry	Open it up for air during sunny days
Cold frame	A box or enclosure that protects the trees	White pine, needle juniper, maple, ume, chojubai, crabapple	Check how dry the pots are every day
Under the eaves	Under the eaves of the house	Satsuki	No rain reaches it, so pots dry out easily
Indoors	A room at 5°C or above	Banyan fig	Keep out of the heater's airflow

The key point: in bonsai winter care, what you are guarding against is less the cold itself than dry wind and frozen pots.

Why let bonsai take frost before moving them in for winter?

Frost tells the tree that winter has come. A tree that has felt the cold gets ready for harder cold.

A bonsai writer's material says that exposing trees for a while to cold enough for frost raises their cold hardiness. Moving them into a warm room because it feels cold to you affects their budding the next year.

Sign	What to look for
The days have shortened	Start preparing for winter
Lows of 5°C or below keep coming	A guide for moving trees into the cold frame
You have seen morning frost 2 to 3 times	The end of the frost exposure period
Trees weak to cold	Protect them early, without waiting for frost

Decide the day to move trees into the cold frame by the frost and temperature signs rather than the calendar month. The signs come early in cold areas and late in warm areas.

Only trees weak to cold can go in before frost. Trees weak to cold do not need frost exposure.

How do a cold frame, under the bench, under the eaves and indoors differ for bonsai winter care?

The difference is how much they keep off wind, frost and chill. A cold frame gives the strongest protection, and indoors is only for trees weak to cold.

What is a cold frame?

A cold frame is a box or enclosure that protects bonsai from cold and dry wind. A full-scale one is a plastic greenhouse or a half-buried pit, but a polystyrene foam box also does the job.

If you keep a cold frame shut, it warms up on sunny days and gets stuffy. On sunny days, open the lid or sheet during the day to let air in.

Ume spends the winter in a cold frame, as the table shows. You can enjoy its flowers that open during winter while it gets ready for budding in spring.

How do you use the space under the bench or under the eaves?

The space under the bench is used by enclosing it with sheeting. Under the eaves suits trees such as satsuki that you want to keep out of frost and cold rain.

Under the bench, enclose the space with two layers of plastic sheeting. Weigh it down so the wind does not lift it. This is the method in a bonsai writer's material, and you can also enclose it with corrugated metal sheets.

Under the eaves keeps off frost and cold rain. On the other hand, no rain reaches the pots, so check often that they have not dried out.

Can you bring bonsai indoors?

Only indoor trees that are weak to cold, such as the banyan fig, should come indoors. Avoid bringing pines or deciduous trees into a heated room.

Material from Hyponex says the banyan fig drops its leaves at 5°C or below. In winter, keep it indoors where the heater's airflow does not reach it.

Indoors, water the banyan fig less often in winter too. Water only after the soil dries well, and empty any water left in the saucer.

The banyan fig is damaged from the cut if it is pruned in winter. Even if long shoots bother you, wait until it is warm to prune.

Indoor banyan fig	Winter care
Spot	A bright room that does not drop below 5°C. Keep out of the heater's airflow
Watering	Less often, only after the soil dries well
Pruning	Not in winter. Wait until it is warm
Leaves have dropped	A sign of cold. Check the temperature where it stands

Pines and deciduous trees can spend the winter outdoors if you keep off frost and dry wind.

Which bonsai are weak to cold in winter?

Of the 13 species in the table, the needle juniper and the banyan fig are weak to cold. Move the needle juniper into a cold frame early, and bring the banyan fig indoors.

Bonsai care calendar by species
Species	Type	Winter spot
Needle juniper	Conifer	Cold frame, moved in early (weak to cold and dry air)
Banyan fig (gajumaru)	Indoor	Indoors (5°C or above)

Source: Kimi's Mini Bonsai Days (needle juniper), e-Bonsai (repotting) / Hyponex Plantia: How to grow gajumaru

Needle juniper is a conifer, but it is weak to cold and dry air. A bonsai writer's material lists needle juniper among the warm-climate species that do not need frost exposure.

The same material also lists these trees as weak to cold.

Citrus, gardenia, camellia
Pomegranate, crape myrtle
Serissa, Yeddo hawthorn
Taiwan boxwood, rockspray cotoneaster, mountain hydrangea

Some trees are hardy to cold but weak to winter dryness. The same material names northern Japanese hemlock and Yezo spruce.

Trees in small pots are also on the protect-early side. Even black pine goes under the eaves or into a cold frame if it is a mini bonsai or a weak tree.

Kou

If you are not sure whether a tree is hardy, move it under the eaves without waiting for frost. In spring you can look up its name and decide its spot for next winter.

How do you prevent dry wind and frozen pots in bonsai winter care?

Keep dry wind off by putting trees under the bench or in a cold frame. Prevent frozen pots by not leaving water in them from evening on.

Even for hardy trees, most winter damage comes from dry wind and freezing. The table sums up the kinds of damage described in a bonsai writer's material.

Winter damage	Cause	Prevention
Twig tips and winter buds die	Dry winter wind	Put trees under the bench or in a cold frame. Move them out of the wind's path
New shoots turn brown	Late frost in early spring	Do not rush them out of the cold frame. Put them back on nights with a frost forecast
Roots are damaged or pots crack	The soil freezes at night	Water in the morning and leave no water overnight
Foliage loses color (pine, shimpaku)	Not enough sun	Give them sun during sunny days
Mold or stuffiness	A shut cold frame	Open it up for air during sunny days

Black pine is tough against both heat and cold. Even so, a bonsai writer's material says to keep it out of strong dry wind in the coldest season.

Maples and cherries are also hardy to cold. The same material says dry outside air and late frost can damage their twigs and new shoots.

For bonsai in winter, decide how to protect them by whether wind hits them and whether the soil freezes, rather than by the temperature reading. On windy days, move the trees on the bench down to the space underneath.

Kou

If the pot surface is frozen white on a winter morning, that spot is too cold. Move the tree to a sunny spot out of the wind, and water once the soil has thawed.

How do you water bonsai in winter?

Water bonsai less often in winter, but do not let them dry out too much. The basic rule is to water in the warmer morning and leave no water at night.

In winter the tree stops growing and takes up less water. Even so, the dry winter air dries the soil faster than you might think.

A bonsai writer's material says to check how dry the trees are once a day, even in a cold frame. Soil that freezes at night harms pots and roots, so water in the morning.

The Omiya Bonsai Art Museum gives winter watering as about once a day. This is a general rule for the museum's bonsai, and pots dry more slowly in a cold frame.

Spot	How it dries	Winter watering
On the bench	Dries fast in dry wind	When the surface is dry, water well in the morning
Under the bench or in a cold frame	Out of the wind, dries slowly	Check every day and water when dry
Under the eaves	No rain reaches it	Check it is not dry even after rainy days
Indoors (banyan fig)	Heating dries it, but the roots take up little water	Less often, only after the soil dries well

You can see winter watering guides for each species by picking a winter month in the "This month" tool below. Do not feed during winter.

Running out of water in winter harms the spring buds. Material on cherries also says winter dryness affects the next year's buds. Watering as a whole is covered in bonsai watering.

What do you do for bonsai in winter?

Try switching the month in the "This month" tool above to December, January or February. It shows that month's jobs for the species you chose, plus a preview of the next month.

The job months are a guide for lowland Kanto (the Tokyo area). Shift them later in colder areas and earlier in warmer areas.

In the coldest part of midwinter, none of the 13 species has any job marked. The marks for pruning and wiring cluster at the start and the end of winter.

Winter work is mostly about resting and protecting the tree, rather than moving branches or buds.

Winter job	What it involves	Aim
Cleaning	Brush the trunk and root spread with a toothbrush to remove moss and dirt	Fewer places for pests to spend the winter
Spraying	Use lime sulfur or similar, following the instructions	Fewer diseases and pests that overwinter
Sun	Give pines and shimpaku sun during sunny days	Keep sun-loving trees from weakening
Airing	Open the cold frame or sheeting during sunny days	Prevent stuffiness
Removing fruit	Take crabapple fruit off by around the turn of the year	Keep the tree from weakening
Feeding	Do not feed	It goes unused in winter and fouls the soil

A bonsai writer's material gives two sprayings as a guide: before trees go into the cold frame, and in the depth of winter. Cleaning and spraying are easier if you finish them before trees go into the cold frame.

Can you prune or wire in winter?

Species marked in the table can be done at the start of winter or before bud break. In the coldest part of midwinter, avoid heavy work on every tree.

Also see the times not to cut in when to prune bonsai. Do not cut maple branches in winter, and do not wire satsuki in winter.

What if you have no winter protection or cold frame?

Even without a cold frame, you can protect trees with a polystyrene foam box, or with a simple cold frame made by enclosing the space under the bench with sheeting. Open it up for air during sunny days.

Alternative	Suited to	Watch out for
Polystyrene foam box	Small bonsai and mini bonsai	Open the lid during sunny days
Enclose the space under the bench with sheeting	Many pots	Use two layers of sheeting and weigh it down
Enclose with corrugated metal sheets	Windy spots	Do not leave it closed and stuffy
Move under the eaves	Trees you want out of frost and cold rain	Watch for drying

Winter protection means enclosing a tree to protect it from cold and wind. A bonsai writer's material also says a polystyrene foam box or a simple cold frame under the bench is enough.

When you enclose trees, closing up is not the end. Count opening up on sunny days as part of the same job.

Kou

A cold frame warms up quickly at midday on sunny days. Remember it as a set: open it in the morning, close it in the evening.

How can you tell if a bonsai has died in winter?

If a deciduous tree has winter buds on its branch tips after dropping its leaves, it is likely to leaf out in spring. If unsure, scrape a little bark off a branch and see whether it is green underneath.

Deciduous trees naturally have no leaves in winter. Do not decide a tree is dead just because its leaves have fallen.

Where to look	Likely alive	Serious damage
Branch tips of deciduous trees	Winter buds are present	No winter buds, and the branches are dry and snap
Under the bark	Green	Brown to black
Foliage of pine or shimpaku	Some green remains	It has turned brown all over
Soil in the pot	Dries as usual	Stays wet all the time

Material from the University of Florida says that if you lightly scrape the bark and it is green underneath, the tree is alive. Cold damage looks worst right after it happens, so wait 3 to 7 days.

Scrape only a little, at the tip of a thin branch that is out of sight. There is still time to decide a tree is dead after you see whether its buds move in spring.

The same material says that if you are unsure, do not cut branches until new shoots appear. Once the buds move in spring, you can see which parts are alive and which are dead.

When does bonsai winter care end?

Take trees out of the cold frame once there is no more risk of late frost. The basic saying is "into the cold frame late, out of it early."

Trees repotted in early spring get used to the outside air little by little, while the cold frame keeps them from drying out. Satsuki repotted in autumn should also come out a little later.

If you take trees outside suddenly, late frost and dry wind damage the new shoots. Start by putting them outside only during the day on sunny days, and get them used to it gradually.

Repotting is covered in when to repot bonsai.

How should you change bonsai winter care in cold or warm areas?

Protect trees earlier in cold areas and later in warm areas. If you go by the frost and temperature signs, you can adjust to your area without memorizing months.

Area	When the signs come	Watch out for
Cold areas	Earlier than lowland Kanto	Frozen pots and soil. Get the cold frame ready early
Lowland Kanto (the Tokyo area)	The baseline for this article	Move trees in after seeing frost 2 to 3 times
Warm areas	Later than lowland Kanto	In years with little frost, decide by whether lows of 5°C or below keep coming

In every area, the foundation of bonsai winter care is not letting the pot soil freeze at night.

What terms come up when talking about bonsai winter care?

Term	Meaning
Overwintering	Getting a tree through the winter without damage until spring
Cold frame	A box or enclosure that protects bonsai from cold and dry wind
Moving in and out	Putting trees into the cold frame, and taking them out of it
On the bench, under the bench	On top of the bonsai bench, and the enclosed space below it
Under the eaves	Under the overhang of the house roof. It keeps off frost and rain
Winter protection	Enclosing a tree to protect it from cold and wind
Warm-climate species	Trees that come from warm regions and are weak to cold
Cold hardiness	A tree's ability to stand the cold
Late frost	Frost that falls after spring has warmed up
Winter buds	Buds that last through the winter and open in spring
Lime sulfur	The general name for a winter spray against diseases and pests

What else should you know alongside bonsai winter care?

Bonsai winter care links to winter watering and to repotting and pruning in spring. You can check the flow of the year in the year calendar.

Year calendarHow to Care for Bonsai: A Yearly Calendar for 13 Species, Seasonal Care, and 3 Basics for BeginnersHow to care for bonsai with a yearly calendar for 13 species, from black pine to maple and satsuki. Repotting, pruning and feeding by group, and fixes.

Watering and seasonsHow Often to Water Bonsai: Seasonal Guide for 13 Species, plus Summer Evenings, Winter, Trips and Drying OutHow often to water bonsai, by season for 13 species. Pot size and spot, how much and when, summer evenings, winter, trips, and drying out vs root rot.

When to do itWhen to Prune Bonsai: Months for 13 Species, Pinching vs Candle Cutting vs Defoliation, When Not to Cut, and WiringWhen to prune bonsai, by month for 13 species from black pine to satsuki. Pinching, candle cutting and defoliation, when not to cut, wiring and fixing mistakes.

When to do itWhen to Repot Bonsai: Months for 13 Species, How Often, Rootbound Signs and AftercareWhen to repot bonsai, by month for 13 species. Spring before bud break is the rule. Exceptions, how often, rootbound signs, steps and aftercare, with sources.

What are common questions about bonsai winter care?

Should you bring bonsai indoors in winter?

Most bonsai spend the winter outdoors. Only trees weak to cold, such as the banyan fig, come indoors.

In a heated room the tree cannot rest over winter, and it buds poorly the next year. Pines and deciduous trees can winter outdoors if you keep off frost and dry wind.

When do you move bonsai into a cold frame?

When the days have shortened and lows of 5°C or below keep coming. Move them in after you have seen morning frost 2 to 3 times.

Trees weak to cold, such as needle juniper, go in without waiting for frost. Deciding by frost and temperature signs instead of months lets you adjust to your area.

How many days apart should you water bonsai in winter?

It depends on the species and the spot. Pick a winter month in the "This month" tool to see a guide for each species.

Do not go by the number of days; check for dryness every day and water in the morning when dry. If the soil is still wet at night, it freezes and harms the roots.

How do you overwinter mini bonsai?

Small pots freeze and dry out easily, so protect them early. Even black pine, which is hardy to cold, goes under the eaves or into a cold frame when the tree is small.

Lining them up in a polystyrene foam box protects them all together. Open the lid during sunny days so they do not get stuffy.

Do you feed bonsai in winter?

No, not during winter. The tree does not use fertilizer in winter, so it only fouls the soil.

A bonsai writer's material says that even winter fertilizer should be removed unless there is a reason for it. Feeding starts again once the buds move in spring. The timing is covered in when to fertilize bonsai.

Bonsai Winter Care: Where to Keep 13 Species, Why Frost Comes First, Cold Frame Alternatives, Winter Watering and Checking for Dead Trees

In short: where should you keep bonsai in winter?

Why let bonsai take frost before moving them in for winter?