Another of the very best bonsai trees for beginners, the Sweetgum (Liquidambar styraciflua) is a member of the family Altingiaceae.
It’s a primary tree, growing to heights of 60-100’. Leaves are 3-6” in length and width on a petiole roughly the same length, and star-shaped.
Bark is gray and deeply furrowed, developing about 10 years after seedling stage.
Growth habit: Sweetgum grows very vigorously, producing shoots in a container that can grow up to two feet in length in a single season. Collected specimens backbud very well, which allows the artist to select the branches necessary for producing a tree-like structure on a small scale. Sweetgum also grows continuously throughout the season. It isn’t bothered significantly by any pests or diseases, aside from munching caterpillars in spring.
Leaf-size reduction: the leaves reduce to about half their normal length with proper pruning and pinching techniques. The petioles shorten as well.
Ramification: simple to produce as the species buds well in the internodes and will continue to do so throughout the life of the tree. A key training technique to ensure the branching remains compact is to remove the terminal buds in late winter. This prevents excessive production of auxin and inhibition of growth in the interior of the branches.
The specimen to your left is showing good development and ramification after only three years of training from a mostly bare trunk.
Root growth: once containerized, Sweetgum produces roots with extreme vigor. Root-pruning should be done every other year without fail, in May or June.
Sweetgum can be affected by hot summer temperatures on the bonsai container.
Roots tend to always seek the edges of containers, and in the high heat of summer pots can get well over 100°F. This scorches the tender roots at the edge of the container, and this is reflected as brown or black edges to the leaves, which are thinner than those of other species.
Providing shade in summer for the tree or just covering the pot can mitigate this problem.
Sources of Sweetgum
Both native Sweetgum and Oriental Sweetgum, Liquidambar Orientalis, are available commercially along with cultivars of both. Bonsai nurseries also offer them.
Seedlings are usually plentiful in areas with mature trees, and these may be collected in May or June along with larger specimens. Always defoliate when collecting Sweetgums regardless of size.
If you collect your own: Sweetgums should be collected in May or June. I always recommend use of a cordless reciprocating saw to make the work easier.
- Cut the trunk to roughly 12-24”, then sever the lateral roots to within 4-6” of the trunk.
- Thrust the blade up under the tree and sever the taproot.
- Most trees should be out of the ground in under five minutes using this tool.
Once it’s time to pot the tree initially, first wash off all the native soil. Then re-cut the roots closer to the trunk in anticipation of the eventual bonsai container.
New roots will sprout mostly from the cut ends of the larger roots, so dust near the ends with rooting powder.
Pot in prepared soil.
Be sure to bury the surface roots to ensure they don’t dry out as the tree recovers.
As a final step, seal every cut on the trunk that’s ¼” or greater in diameter with cut paste.
Watering: normal watering routine. Always use a well-draining soil.
Feeding: either organic or inorganic at full strength during the growing season. No special requirements.
So What Do You Think?
Sweetgum is a great tree for beginners or even seasoned bonsai artists. But I would really enjoy hearing your thoughts and your suggestions! I’m always happy to answer any questions you have. Just leave your comment(s) below and I’ll respond to you right away.