I recently was given a small Tsuma Gaki Japanese Maple. It is currently in a 15 inch pot, which it has obviously been in for a long time. It is currently 39″ high and 45″ wide. I would like to place it in a spot of my garden that is sunny. I have a watering system, so it will be watered regularly. I’ve read about this tree and it is slow growing but can reach 10 feet in height. I’ve also read that it can be kept smaller, which I would like to do, by keeping it in a pot. So my question is, how would I best keep it to a small size, say 5 feet in height max? Could I do this by transplanting it into a bigger pot (if so, how big) and burying it in the ground? Or could I do so by pruning it heavily? Any advice would be greatly appreciated, as it is a lovely little tree and I’d really like to take care of it well but at the same time have it fit well into my garden.
Many thanks!
Thank you for contacting the Toronto Master Gardeners. You have a beautiful small tree! Both of the methods you have researched are possible approaches to limiting the size of this tree. You can keep the tree in a pot. If you upsize the pot it has been advised that the pot should not exceed twice the diameter of the rootball and an additional half the depth of the root ball container planting. If you repot the tree, wash off some of the soil, take the opportunity to look at the roots, untangle them a bit and prune away any unhealthy looking roots. Use a container potting soil mix. Challenges to consider with container planting include having the tree become pot-bound with roots circling the pot and decreasing the efficiency of taking up nutrients. If you choose to bury the pot, ensure it has lots of drainage holes. You don’t want the buried pot to become soggy, as this can lead to root rot, also impacting the health of the tree. Another option of keeping the tree in a pot is placing it out in the garden in the growing season but overwintering in an unheated garage or shed or cold cellar. This answer to a previous question about Japanese Maples on our website has information about how to do this overwintering.
Planting the tree directly into the ground is your other option. In this case, you would prune the tree to maintain its shape and size. It is best to prune a maple while it’s dormant in late winter or in the mid to late summer. When pruning, follow a larger / longer branch back to a side branch and cut with sharp shears just distal to this junction. Trim away any branches that are criss-crossing the canopy – sometimes called “buggy whip” branches as they are often thin and flexible. This helps to maintain the graceful tiered shape of the tree. This reference may be helpful in terms of pruning your Tsuma Gaki Japanese maple Pruning. An article in this issue of the Toronto Botanical Garden Trellis magazine also has helpful information Trellis – Japanese Maples.
Two Toronto Master Garden Guides are recommended for your information related to both planting and growing Japanese Maples – Planting a Tree for Life Planting a Tree and Growing Japanese Maples Growing Japanese Maples.
Best of luck with your Tsuma Gaki Japanese Maple!
June 5, 2022