If you have a bonsai that you’ve worked so hard to perfect, you may be wondering if it can survive the winter outdoors.
And this question is quite important because you don’t want all your work to disappear.
Well, bonsais, just like other trees, can survive the winter with the proper care.
Proper overwintering techniques for your bonsai can range from bringing your tree indoors, keeping it in a greenhouse or cold frame, or even replanting the tree in a garden to keep its roots warm.
Overall, what you need to do for your plant in the winter depends on the species and your geographical location.
In this article, we’ll examine how to ensure your bonsai survives the winter.
Caring for Bonsais in Winter
Bonsais can survive winter conditions just like any other tree, but you will need to consider the weather in your geographic location when deciding how to care for your plant.
What you should do with your bonsai in the winter also depends on whether you have an indoor or outdoor tree.
Indoor Bonsai Trees in Winter
You should keep indoor bonsai trees, such as the tropical and subtropical species of ficus, jade, Fukien tea, and Hawaiian umbrella, in an area of your home during winter that receives a lot of sunlight.
South-facing windows tend to give off the most light, making them perfect places for your tree to spend the cold months.
Additionally, make sure you keep your thermostat set in such a way that your house stays reasonably warm, even while you’re away for work or vacation.
You can also consider investing in a fluorescent plant light to give your bonsai some extra light during shorter winter days.
And always maintain humidity for your bonsai by spritzing it often with water and keeping the soil damp but not soggy.
You can even run a humidifier if the winter air in your region is particularly dry.
Outdoor Bonsai Trees in Winter
Just as other trees go dormant in the winter and come back to life in spring, so, too, can outdoor bonsai trees.
But they’ll need a little help to do this.
Come fall, resist the temptation to move your bonsai indoors as the weather begins to chill.
The bonsai needs these cooler temperatures to begin the process of dormancy.
Then, after the first frost, you can determine the next steps for your bonsai tree’s dormancy period.
Regions With Winter Temperatures Lower Than 15 Degrees Fahrenheit (-9 C)
If temperatures dip below 15 degrees Fahrenheit (-9 C) in your area, plan to move your bonsai tree to a greenhouse or a cold frame to protect it from harsh wind and other severe weather.
The winter storage is less to keep your bonsai warm and more to protect it from dramatic temperature swings and physical damage.
Regions with Winter Temperatures Above 25 Degrees Fahrenheit (-4 C)
If temperatures remain above approximately 25 degrees Fahrenheit (-4 C) in your area, your bonsai can stay outside as long as you protect it from high winds.
So, you should keep it low to the ground or consider planting it temporarily in a garden bed to protect its physical form and keep its roots warm enough.
However, never let your bonsai get too warm during winter, or it will come out of dormancy and may start budding.
These buds are unlikely to survive, which will damage your entire bonsai tree.
When Is the Temperature Too Cold for an Outdoor Bonsai?
Cold-weather bonsai trees require a dormancy period to thrive, so even freezing weather isn’t necessarily bad for these plants.
But you should never let your bonsai get so cold that its roots freeze.
Frozen roots on a bonsai tree mean certain death.
So, if you’re expecting a winter with prolonged temperatures below freezing, take proper care of your bonsai while still keeping it in its dormant state by moving it to some form of winter storage.
This storage space will protect its roots from freezing and save its branches from harsh winter conditions.
But, just make sure that the storage area is not too warm.
Otherwise, you will disturb your tree’s dormancy period.
Can Bonsai Trees Stay Outside in Winter?
Bonsai trees can and should stay outside in winter if they are an outdoor bonsai species.
These bonsai trees can survive through the seasons by entering a natural dormancy cycle in late fall and winter.
If you bring your outdoor bonsai trees inside during winter, they can’t enter dormancy and may die.
On the other hand, you should keep tropical and subtropical bonsai trees indoors during winter, even if you put them outside during the summer months for sunlight purposes.
Thus, before temperatures drop beneath 45 degrees Fahrenheit (7 C), bring your tropical bonsai back inside as they do not tolerate cold conditions.
Best Bonsais for Cold Climates
Some species of bonsai trees can survive and even thrive in colder climates due to their subtropical origins.
So, people who want to keep bonsai trees in more northern locales should look for cold-hardy species of bonsai that thrive in four-season conditions, such as the options listed below.
Most birch bonsai trees do well in cold regions.
They’re also a preferred species for people who want a fast-growing plant.
Look specifically for eastern red cedar, eastern white cedar, or Lebanon cedar.
Cypress bonsai such as blue moss and Emerald Isle do particularly well in colder climates.
Look specifically for Siberian elm as opposed to Chinese elm.
The Hornbeam bonsai has some varieties that don’t do well in the cold.
So, choose the American Hornbeam, which can survive winters.
Larch bonsai is native to the northern hemisphere.
It will shed its needles during fall before it enters dormancy.
Maple bonsai do well in cold and outdoor environments, such as the Amur, field, and hedge maples.
Pine can easily survive brutal winter conditions, and the pine bonsai is no different.
Look for Japanese, mugo, and Swiss mountain varieties.
Sargent Crabapple Bonsai
This flowering bonsai varietal has no problem getting through cold winters.
Though most spruce bonsai can tolerate cold, not all can survive during the harshest of winters.
However, those that originate from chilly environments can easily handle the cold.
So, look for Alberta and Norway varieties if you live in a frigid climate.
Many species of bonsai trees can survive and thrive in harsh winter conditions, and some even require it for dormancy.
But, others need special care during the cold season.
So, be sure to understand the level at which your bonsai tree can tolerate cold by properly researching its species and understanding the winter conditions in your region.
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