Plant of the Month October: Liquidambar styraciflua — Sweetgum

This month we’d like to introduce you to a tree that’s made it all the way from North America to the gardens and parks of Europe: Liquidambar styraciflua, also known simply as the sweetgum.

 

Its exceptional autumnal colouring is winning it ever more fans

In the northern states of the USA and Canada the first night frosts coupled with warm days give rise to the phenomenon known as Indian summer, when the deciduous and mixed forests of the region are glorious with vivid autumnal colouring. Anyone looking to enjoy the same spectacle in their own garden can be assured of covering the whole spectrum of autumn colours with the sweetgum. Its leaf colouring ranges from a lush light green in summer, turning through orange-red to a dark violet-brown during the autumn months.

 

Special features: colour, shape and fruit

At first glance, the leaves of the sweetgum are easily confused with those of the maple. The sweetgum’s leaves are also 5-7 lobed and taper to a point. However, those from the sweetgum grow on the branch in an alternating pattern, whereas the leaves of the maple grow in pairs on opposite sides of the branch. The fruit also has noticeable differences. The sweetgum doesn’t tend to bloom until it’s a good twenty years old. It’s also monoecious, which means that it grows both male and female blooms. These grow into spiky, round green fruit which hang in bunches from the tree. During the autumn months they slowly dry out and turn brown, until they split apart and the seeds are released.

The sweetgum can reach to a stately height of 12m. Since it has an oval shape and is not a tree that spreads outwards too much, it’s also suitable for smaller locations. In order to thrive, the sweetgum needs a sunny and wind-protected place. It prefers humus-rich, loamy soil and a lightly alkaline pH value. However if the earth is too acidic and chalky, the leaves tend to turn yellow in the spring and summer. The Liquidambar doesn’t like waterlogging—to ensure lightly moist and porous soil conditions, use bark mulch or chips of pinewood, which should be laid as the uppermost layer when planting the tree.

The sweetgum doesn’t mind cold temperatures—at least not the larger trees. Younger trees however should be protected adequately against the winter cold.