Liquidambar/Sweetgum, Liquidambar styraciflua

Adult height: 18m although in the wild can be almost twice this height

Description: Deciduous tree, glossy green leaves through spring and summer, turning to burnt reds and brilliant yellows in autumn.

Photo: Forest & Kim Starr

The Liquidambar is a beautiful choice of tree. With its oval shape and brilliant leaf display, it’s hardy nature and rapid growth rate it is the ideal feature tree for a garden or out on the farm.
This large shade tree usually forms a wide base, in some cases more than 10m wide. It loves full sun right through to partial sun but does best in soil that is moist, deep and rich.

In its native US home it's known as the Sweetgum because of the sweetly fragrant sap found under its bark. It’s Latin name Liquidambar styraciflua translates as “flowing with styrax” or sweet gum, hence the name. This sap has been used for thousands of years for flavouring and as a medicine.

Photo: Forest & Kim Starr

After about 15 years the tree develops prominent green fruits that are suspended on long spines that slowly turn brown in autumn - these have been likened to the “Death Stars” that featured in the Star Wars movies. Little ‘beaks’ open in late autumn releasing the seeds. While these are lovely they do create a problem for lawn mowers and can clog up drains and gutters. They are also painful to walk on so it pays to keep a Liquidambar away from foot paths, and it's why you never see its glorious colours on golf fairways.

While the tree is glamorous, as it gets old it is very common for them to lose the main leader due to storm damage or winter frosts killing buds. Older trees tend to from umbrella-like canopies instead of the more common pyramid shape of youth.

The Liquidambar does tend to like an acidy soil and will suffer from marked foliage if planted in alkaline soils. It also needs lots of room because it has a spreading root base.

While the wood is termed weak (making it more prone to breaking off) it is used commercially for furniture and plywood.

Photo: Forest & Kim Starr

There are some reports of Liquidambar wood being toxic to animals so be cautious if animals are grazing around it or if you are planning to throw cuttings over the fence for stock. Burning it is also not encouraged as the smoke it produces can also be toxic.

Don’t put a sweet gum too close to the house, since the mature trees can drop big limbs in winter storms. Sweet gums, when mature, will kill the grass with their dense shade and shallow roots, so they are best standing guard over the shade garden, cooling the driveway and sidewalk, or at the pond’s or wood’s edge.

The only other consideration in site choice is that the trees need neutral to slightly acid soil and, like the red maple, will develop iron chlorosis of the foliage (leaf goes yellow between the veins) if the soil is too alkaline.

Nadene Hall
NZ Lifestyle Block magazine