Overwintering Emerald Cedar Tree in a Pot*

(Question)

I live in Northern Ontario. Can Emerald Cedar tree survive in it’s pot over the winter and how should I winterize the tree. If the tree will not survive, what should I do to until I can plant it in the spring.

(Answer)

Ideally, the emerald cedar (Thuja occidentalis ‘Smaragd’) should be planted in the ground as opposed to being left in the pot over the winter. But it’s now mid-November and in Northern Ontario, the ground is likely already too cold for planting the tree – the tree needs some time to settle in before the ground freezes.

I suggest that you keep the tree in the container and move it to a sheltered, cool spot (e.g., the garage) over the winter. If the roots thaw out over the winter, water the tree every couple of weeks to ensure the roots stay hydrated. Plant it outdoors next May or June, or in the autumn. Alternatively, if the ground is not yet frozen you could dig a hole and temporarily sink the pot into your garden over the winter. You will need a protected area in your garden without too much winter sun and you will need to make sure it is well watered before the soil freezes.

Here are some helpful resources for your tree:

As well, there is a lot of good general information on emerald cedars posted to the Toronto Master Gardeners – take a look at our Ask a Master Gardener website (torontomastergardeners.ca) and search on the term “emerald cedar”.