Sweet Gum Tree


Sweet Gum trees are large trees native to North America that are commonly used in landscaping or street trees. In this article I will tell you all the key facts about what a Sweet Gum Tree is, from basic growth characteristics to whether Sweet Gum is a good choice for landscaping your yard. But let’s start by looking at the typical size / growing requirements of this tree:

Sweet Gum Tree Reference Table, Growing Conditions & Facts

Common NameSweet Gum Tree, Red Gum, Alligator Wood
Scientific NameLiquidambar styraciflua
Garden ZonesUSDA Zone 5-9
Mature Height60-75′ (18-23 m)
Spread / Spacing40-50′ (12-15 m)
Sun RequirementsFull Sun
Soil TypeAcidic, Sandy to Clay
Growth Rate1-2′ per year (30-60 cm)
Tree ShapeOvular / Oval
Reference [1]

Facts about the Sweet Gum tree

  • The common name, Sweet Gum comes from the sap that oozes from just under the bark
  • Syrup can be made from the sap of Sweet Gum trees
  • A large tree with a symmetrical shape, Sweet Gum trees can make great shade trees
  • Birds love to pick the seeds out of the seed pods
  • Sweet Gum tree seeds contain an important ingredient for the medicine, Tamiflu
  • Native Range of the Sweet Gum tree is from Texas to NY, and all areas South East of that border.

General characteristics of the Sweet Gum Tree

Sweet Gum trees are large deciduous trees with beautiful ovular/oval shape. They are long lived, with ages reaching 100-150 years old. Once a tree reaches 20-30 years in age it will start producing seed pods. Numerous spike-ball shaped seed pods can be produced each year.

Sweet Gums are known as a colonizing trees, meaning that they will spread aggressively in disturbed areas with little vegetation. In well established sites, Sweet Gum trees will not spread. Note, that small saplings are easily removed.

Growing Conditions for Sweet Gum Tree

Sweet Gum trees should be grown in full sun and well draining soil. They prefer well draining loamy soil that is slightly acidic. But they are highly adaptable, and can grow in nearly any type of soil as long as it is not alkaline or too dry. Additionally, they can grow in partial shade, but you should try to avoid this (continued below).

An important note – Sweet Gum trees should be grown in full sun

Although it is possible for Sweet Gum trees to grow in partial shade, this should be avoided. Sweet Gum trees should be grown in full sun to ensure a strong trunk that won’t buckle. If shaded laterally, the tree will add height prematurely in an attempt to obtain more sunlight.

Studies have shown that Sweet Gum trees that are shaded laterally, or in the presence of competition will result in height/girth ratios that are too high.[2] This condition can result in the tree toppling over from sway, a condition where growth rings are uneven through the cross section of the tree.

Sweet Gum Tree for landscaping

Sweet Gum trees will grow large and can make excellent shade trees for a home. In optimum conditions Sweet Gum trees will grow up to 2′ per year, making them a potentially fast growing shade tree. Commonly planted as street trees, the primary drawback is the seed balls that they seemingly produce year round.

Fall color of Sweet Gum trees are red in appearance, and quite dramatic. This makes the Sweetgum an excellent addition to any fall display.

These beautiful star-shaped leaves turn a deep red color in Autumn

These seed balls are about the size of golf balls, round and covered with spines or spikes. Sweet Gum seed pods will cause pain when stepped on with bare feet. And, dogs don’t appreciate stepping on the seed pods either.

Sweet Gum Seed Pods

The small, spiny seed pods from the Sweet Gum tree can cause grief to some homeowners and their pets. The seed pods can litter sidewalks and driveways, causing a potential tripping hazard [5]. Additionally if one steps on a pod barefoot, it will hurt. The hazard from stepping on a seed pod also extends to pets, particularly getting the pods stuck in the paws of dogs.

So, if you are interested in landscaping with a Sweet Gum tree, perhaps consider growing it a good distance from a driveway, sidewalk or street. Or, consider buying a ‘bagger’ picker-upper for collecting the pods.

Sweet Gum seed pods: Not as dangerous as some media make them out to be…

A note from my own personal experience: There are several Sweet Gum trees that border the street in our neighborhood. And I’ve always admired their shape and fall color. I’ve found that the seed pods tend to crush under my foot and pose no tripping hazard.

Over the years I’ve tested this several times as I take my children for walks. I’ve also held and squeezed them in my hand, with no adverse issue. So, I think a lot of the recent criticism of this tree is overblown, or perhaps unwarranted.

Potential Problems for Sweet Gum Trees

Diseases

Like many trees, Sweet Gum is not without potential diseases. The primary disease problem Sweet Gum trees can face is a blight caused by drought, Botryosphaeria ribis [3]. As a Fungus, this disease will strengthen with more shade [4].

Additionally Sweet Gum trees can be attacked by common pests such as Spider Mites, Aphids, caterpillars, etc.

Fauna

Small mammals will damage young Sweet Gum trees. Damage to young Sweet Gum saplings has been documented to be a major concern in Sweet Gum plantations, primarily from rabbits and mice [3].

The seeds contained within the pods of Sweet Gum trees are a favorite of Goldfinches, Nuthatches, and other songbirds.

Mushrooms

Sweet Gum Trees support the growth of several varieties of mushrooms [1]. Namely Reishi, Oyster Mushroom, and Tiger Sawgill.

Sweet Gum Tree Botanical Information

Reaching heights of 70′ (21 m) when mature, Sweet Gum trees will have significant branching in symmetrical form. Over all, mature trees will have a oval or rounded shape, while younger trees will be more pyramidal in shape. Depending on conditions, Sweet Gum trees can grow up to 2′ per year. The lovely fall color make this deciduous tree a great choice for landscaping.

Bark

The bark of the Sweet Gum tree consists of rounded/rough vertical ridges. Another common name for Sweet Gum tree is ‘alligator skin’, as the bark can resemble the skin of the alligator.

Leaves

Sweet Gum tree Leaves are a 5 point/lobed star. They are easily identifiable and nearly unmistakable for any other tree leaf.

Flower / Seed Pod

Small, green flowers are produced from March to late May depending on conditions and geography. The fruiting heads/balls will fade to yellow as Autumn approaches, normally around September.

Each seed ball will contain from 7-57 seeds depending on conditions. Prolonged drought will result in fewer seeds produced per ball.

Roots

Sweet Gum produces a taproot and numerous shallow lateral roots that can be suckering. Lateral roots are shallow and can lead to trees tipping over or lifting sidewalks/driveways. Observations have shown that the soil conditions will dictate the rooting system.

  • Sweet Gum Trees will develop tap and lateral roots on well drained sites
  • On overly moist, or poor draining sites, Sweet Gum Trees will no develop much of a taproot.
The horizontal roots are suckering

Additionally, Sweet Gum trees will sucker if cut down. Suckering is a process where new trees sprout from horizontal, or lateral roots.So, removal of a tree from a yard or area will generally result in sprouting of numerous new trees.

After logging operations, 1/2 of the regenerative seedlings of Sweet Gum are thought to be from suckering. While the other saplings are from seed.

Want to learn more on finding and identifying Sweet Gum Trees?

The why not read our Sweet Gum Identification Guide? Click below!

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References:

[1] – Silvics of North America: Conifers. By Russell M. Burns

[2] – INFLUENCE OF NEIGHBORS ON TREE FORM: EFFECTS OF LATERAL SHADE AND PREVENTION OF SWAY ON THE ALLOMETRY OF LIQUIDAMBAR STYRACIFLUA (SWEET GUM)

[3] – Diseases of Forest and Shade Trees of the United States. p386. By George Henry Hepting

[4] – Fertilization and Irrigation Effect on Botryosphaeriaceae Canker Development in Intensively Managed Sweetgum (Liquidambar styraciflua). Michelle M. Cram, David R. Coyle, Pauline Spaine, Sharon V. Lumpkin, and Mark D. Coleman

[5] – Negative Aspects and Hazardous Effects of Forest Environment on Human Health. Marek TomalakEmail authorElio RossiFrancesco FerriniPaola A. Moro

Joe Foster

Hi - I grew up outdoors in nature - hiking, fishing, hunting. In high school I got my first job at a garden center where I learned to garden and landscape. I've been growing plants from seed and designing native plant gardens for over six years. I hope to share some of my knowledge with you! Additionally I am a wood worker / DIY enthusiast. I enjoy designing/building projects (with hand tools when I can!). I hope to give you some tips and useful information!

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