When is the best time to plant a Japanese maple in a container. The container will be on a balcony, six stories up. It will receive late afternoon (3:30 on) sun and will experience windy conditions. The container is self-watering from under the roots, up.
Thank you for contacting Toronto Master Gardeners with your question.
Japanese maples are very popular, especially in urban areas and in balcony gardens. Your question has been asked in the past, and the answer that most closely pertains to you is posted on our website. I have copied it below my comments.
You have a few things to consider that are a bit different from this post. First, you need to check for a hardy variety of Japanese maple, preferably one that is hardy in zone 5. Toronto is zone 6a.
Also wind is a serious consideration, as the tree will dry quickly; Japanese maples like lots of water, so your care must be constant and consistent. Add a mulch that will not blow away, as the self-watering from the bottom may never reach the surface soil in the container.
You mention afternoon/west sun, which can affect the foliage by bleaching it to a paler colour. Again, protection may be needed.
Here is the best answer from our website: select Japanese maples in containers inthe Search area.
“Yes you can grow a Japanese maple in a container but there are several things to consider. The first is that because it is a tree you are growing it should be a very large container (at least as wide as the ultimate width of the mature tree). You should also be aware of the weight of this container may not be safe on your balcony. You don’t say what floor you are on, but this is an important consideration in your choice of plants. You should try to select a variety that is hardy to at least two zones colder than the one you are in. (e.g. choose a plant hardy to zone 4 or lower if you live in a zone 6 area). In the Toronto area (zone 6) this might be a problem because most Japanese maples are only hardy up to zone 6. This is because the higher up off the ground you are the colder the winter winds are and because of the freeze/thaw cycles that containers inevitable undergo. An east exposure is however one of the best because in Ontario we often get northwest winter winds which can severely damage plants. You might consider wrapping your tree with burlap in the winter months or if you have access to a garden digging a hole and sinking the pot up to the rim in soil for the winter. You will find that the Acer palmatum varieties are the ones that have the lowest hardiness rating. Avoid those plants that have deeply dissected leaves as they naturally have a more delicate leaf structure which may not take the wind.
Japanese maples will grow in varying amounts of light from full sun to shade but do best if protected from mid-day sun. ”
You can use a bagged triple mix soil. To find more growing information click on this link
References
:https://forums.botanicalgarden.ubc.ca/threads/japanese-maples-for-containers.91704/
https://landscapeontario.com/japanese-maples