Preparing Your Bonsai for Winter – Your Checklist

The cold season can be a tough challenge for bonsai enthusiasts. Preparing bonsai for winter is a task you need to add to your list, if you wish to keep your trees healthy all year around. 

In this article we take a look at the tasks you need to do in preparation for the winter season. We also give you a handy bonsai tree winter checklist, so you don’t miss out on anything important. 

How to Prepare Your Bonsai Trees for Winter? 

So, what does preparing a bonsai for winter involve? Here are the tasks you need to do before winter to ensure your tree remains healthy. 

Fertilise your tree during summer and early autumn

Preparing a bonsai for winter actually starts as early as summer. During the growing season trees produce sugars and carbohydrates, which they use in winter to protect themselves from freezing. It’s important to fertilise your trees during the summer and autumn months to ensure it has enough carbohydrates to survive winter. 

Remove dead leaves

Removing dead leaves and clearing the pot of any debris is another task to add to your checklist. While dormant, your bonsai does not need foliage to survive, so removing dead leaves will help your tree stay healthy during winter. Insects can often overwinter between the leaves which put your tree at risk of an infestation. The foliage also retains moisture around the trunk, predisposing the growth of fungi or moss. 

This doesn’t mean you need to pick off every single leaf. Your tree will naturally start losing leaves in autumn. All you need to do is remove the dead leaves once they drop.

Make sure your tree is protected from rain

Oftentimes moisture can do more damage than the cold. In a place with particularly wet winters, like here in the United Kingdom, rain can be particularly dangerous for your tree. Water sitting the pot of your bonsai for long periods of time will eventually lead to root rot. 

Before winter make sure the soil your tree is planted in is draining properly and if needed, repot it. We recommend staying away from compost-rich soil as this tends to retain water. It’s also a good idea to keep your bonsai tree out of the rain so you have better control over the amount of water it gets. 

Move your tree into a sheltered location

What makes cold weather so dangerous is the risk of dehydration. If the roots of your trees freeze, they can’t perform their basic function meaning your tree will dehydrate and wither. Strong winds and the winter sun can only make this worse. 

Once temperatures start to drop, move your tree into a sheltered location away from wind or sun. 

Monitor root health 

While your tree won’t require frequent fertilising or watering during the winter months, it’s still important to monitor its root health. The cold weather can cause tree roots to become more brittle which can lead to damage. When the weather starts to get milder towards spring ensure your tree is thoroughly watered and inspect the roots. If there’s any roots that are dried or damaged, we would recommend cutting them off to allow your tree to flourish. 

Don’t rush into bringing your tree indoors

It might be tempting to bring your tree indoors as winter approaches. However, this is not a good idea and let us explain why. Bringing your bonsai in your home where it’s significantly warmer than outdoors, can result in your tree not entering dormancy. In fact, it can encourage your tree to continue growing throughout winter. 

This means your tree’s natural cycle is distorted. Tropical bonsai trees don’t need a dormancy period due to their natural environment. For trees from temperate climates on the other hand, the dormancy period is essential for healthy growth.   

Our bonsai winter checklist can help you remember all the important maintenance tasks at hand:

How to Protect Your Bonsai From Winter Frost? 

If the temperatures get too cold, the roots of your bonsai could completely freeze, damaging or even worse killing your tree. Shallow pots which are popular for bonsai, can be dangerous for the roots of your tree during winter. Since there is less soil in the pot, there is less insulation around the roots, leaving them exposed to the freezing temperatures. 

The best way to protect the roots of your tree during winter is to keep your bonsai in a greenhouse or cold frame, where they can be sheltered from the elements. In addition, they will continue to get enough sunlight to maintain growth come spring. 

Another option for winter bonsai protection is to use a special frost protection fleece. These ‘jackets’ promote heat retention while still allowing air and moisture to reach your bonsai, effectively shielding it from the elements. 

If you live in a place with mild winters, you can also plant your bonsai directly in the ground for the frosty months. This way your tree’s roots are insulated from frost and can draw moisture directly from the ground.  

Where to Store Your Bonsai Trees in Winter? 

Choosing the right place to store your bonsai over winter is essential to keeping your tree healthy. Depending on your local climate as well as the species of your bonsai, you have the options of storing it indoors or in a sheltered outdoor location. 

Indoor Storage Options:

• Conservatory or sunroom – If your home has a conservatory or sunroom, you should consider yourself lucky. Their ample amount of natural light makes them a prime winter location for your bonsai trees. Tropical trees in particular will thrive in a sunroom. 
• Greenhouse – A greenhouse is another perfect location for winter bonsai storage. The controlled environment in a greenhouse will help keep your tree safe not only from frost, but also from pests or other threats. 
• Basement – Not many houses in the UK have a basement but if yours does, it can be a great place to keep your tree protected from the fluctuating temperatures outside. 

Outdoor Storage Options:

• Cold frames – The less intricate version of greenhouses, cold frames provide excellent protection against winter frost. And the best part is you can easily DIY one. You can use PVC pipes and transparent plastic or even old window frames to create a secure structure where your trees can stay during the winter months. 
• Shed or Garage – If you have a shed or garage, this can be the ideal location for overwintering your trees. Make sure you check on your bonsai throughout winter to ensure they don’t freeze over if the temperature drops too much. 

More Bonsai Care Tips with Bonsai 2 U 

If you’re looking for more tips on how to take care of your bonsai tree collection, why not visit our Bonsai Care Hub? There you will find useful guides on how to prune, repot or shape your tree. As experts in all things bonsai, here at Bonsai 2 U, we aim to provide enthusiasts of all levels with the knowledge to keep your bonsai trees healthy and thriving. 

In addition, we supply all of the tools and accessories needed for regular bonsai maintenance along with a stunning collection of outdoor and indoor bonsai trees. Shop our products online or visit us in person in our Lutterworth bonsai nursery.