Hi there! I was given a Juniper bonsai tree as a gift last week and I was hoping to get some overwintering advice, as it is my first bonsai tree. From my research I know that normally a Juniper bonsai should be kept outside in the winter but due to the fluctuating warm temperatures (I live in Toronto), I’m not sure if the tree will go into dormancy. The tree is currently in my garage. I am wondering if I should keep the tree in my garage, move it into my fridge, bury it outside, or an alternative option. Please let me know what you would recommend.
Thanks for your question. If possible, you should determine whether your particular bonsai is a warm climate or cold climate juniper, as the care needs will be different. If it’s a warm climate juniper, it may not require winter dormancy and in fact may suffer from exposure to cold conditions. If it’s a cold climate juniper, then it’s important to consider how it has been growing for most of this winter. Before you received the bonsai as a gift, chances are it was probably growing in a garden centre or other indoor retail environment. Since winter dormancy for cold climate junipers should last about three months, it is unlikely that you will achieve this without resorting to artificial measures to extend the dormancy period.
Instead of keeping your bonsai in the garage, I would suggest bringing it back indoors. Assume that it will not undergo a dormancy period this season, and care for it as you would during warmer months (see links below). Then, next fall, when the timing is appropriate (and assuming it is a cold climate juniper), provide the necessary conditions to allow it to undergo a proper winter dormancy for the necessary duration.
The following links will help you care for your new bonsai:
The Art of Bonsai: A Toronto Master Gardener’s Guide
Toronto Bonsai Society