Tricia Smyth, from Essence of the Tree, was at the nursery recently to give a workshop on creating container gardens with Japanese maples. She brought specimens with her to show, step-by-step, how to plant a new container garden and how to root prune an older tree to keep it looking fresh.
She began by explaining the importance of good drainage for trees in containers. The soil mix she has created for hers contains pumice, which facilitates good drainage. She likes pots with lots of holes in the bottom, and does not agree with the practice of plugging holes with rock because it slows the movement of water through the soil.
Once you've selected the pot and a soil mix, the next consideration is the aesthetic quality of the tree. She looks for trees with a form that flows - she describes them as trees with "movement." The positioning of the tree in the container and careful pruning will enhance this quality over time.
When the tree is planted, Tricia adds small, shallow-rooted perennials to create a miniature garden. These plants should not be aggressive either in their appearance or in their growth habit - the Japanese maple should be the star of the show. The companion plants are there to add some seasonal interest and color contrast.
Tricia recommends using a fertilizer with a low nitrogen to phosporus ratio. This promotes slow steady growth and a strong root system.
After 3 to 5 years, it is time to root prune and re-pot the Japanese maple. Tricia demonstrated this with an older tree she brought to the workshop. The process is straighforward - simply take the tree out of the container and remove the depleted soil from around the root ball. Look for any large roots that may be circling, or girdling, the tree and remove them. After that, give the root mass a haircut, removing no more than one-third of the volume.
Add fresh soil to the container and replant your Japanese maple. With regular care, your container garden will give you enjoyment for many years to come.
Inspired to create your own container garden? Keep in mind that West Seattle Nursery carries over 200 varieties of Japanese maples. Click here to view a searchable list of the trees we have for 2016.