liquidambar

( li - kwid - AM - bar )

At-A-Glance Information

This genus, commonly known as Sweet Gum, Star Gum, Red Gum, Satin-Walnut or American Storax, is made up of deciduous trees that need full sun and moderate to regular water to perform well. Sweet Gum will attract birds to your garden. The foliage is beautiful, turning brilliant colors in fall, and casts good shade in summertime. Younger trees have an upright habit, while mature ones have spreading canopies. Flowers are inconspicuous. Spiky ball-shaped fruits fall from trees throughout the year. They are good street trees if given enough distance from sidewalks and roads; their root systems will raise paved surfaces. Use these trees in the landscape as shade trees, accents, background plantings, or simply to add fall color to the garden. Although these plants are not considered toxic, their spiky seed balls can be a physical hazard to grazing animals and barefoot humans.

liquidambar Species and Varietals

Liquidambar is a member of the plant family Altingiaceae, and includes 15 extant species. The best growing zones for Sweet Gum trees vary depending on the species. The common name for Liquidambar trees, Sweet Gum, refers to the sweet-smelling resin that the trees exude when damaged. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Liquidambar acalycina (Chang's Sweet Gum)
Native to southern China, these trees reach between 30-50 feet tall and have a crown that spread to 20-30 feet wide. Leaves turn red in autumn before falling. Bark is brown to black in color. Flowers are insignifcant and yellow-green. Hardy down to 5 degrees Fahrenheit, these trees prefer full sun to partial shade. Variety 'Burgundy Flush' has purple new leaves that mature to green, turning burgundy-red in fall.

Liquidambar cambodiana (Sdey)
Endemic to southwestern areas of Cambodia, this species of Sweet Gum reaches between 26 and 33 feet tall when mature. Upper sides of leaves are glossy. These trees have not been seen growing naturally in their native range for a few decades, so the species may be extinct.

Liquidambar excelsa (Noronha)
These trees are native to Tibet, Yunnan Province in China, the eastern Himalayas, Assam, Bangladesh, and Southeastern Asia. They can reach upwards of 200 feet tall at maturity, and are typically found growing naturally in wet tropical forested areas. Leaves are simple.

Liquidambar formosana (Formosan Gum, Chinese Sweet Gum, Formosa Sweet Gum)
Best in zones 4-9, 14-24, and native to East Asia, this tree reaches 40-60 feet tall and 25 feet wide. Forms vary depending on individual trees. Leaves are violet when new, mature to deep green, and turn red to yellow in fall. Leaves drop in early wintertime and have three lobes.​

Liquidambar orientalis (Oriental Sweetgum, Turkish Sweetgum)
Native to floodplains in the eastern Mediterranean region, these deciduous trees reach between 98 and 115 feet tall at maturity. These attractive landscape ornamentals are valued for their colorful fall leaves and grow well in areas with mean annual temperatures around 65 degrees Fahrenheit. Bark is greyish-brown and fissured on mature trees.
Liquidambar styraciflua (American Sweet Gum, American Storax, Hazel Pie, Bilsted, Redgum, Satin-Walnut, Star-Leaved Gum, Alligatorwood, Gumball Tree)
This species of Sweet Gum is native to the eastern United States and grows well in zones 3-9 and 14-24. It reaches around 60 feet tall in gardens, but can get much taller in larger spaces, and spreads to 20-25 feet wide. Bark is furrowed and branches have a pleasing pattern to them. Leaves are deep green in spring and summertime, and turn purple, yellow, or red in fall.
'Burgundy'
Deep purple-red fall color, and foliage hangs on for a long time, sometimes even through winter.
'Cherokee'
Produces few seedpods; fall color is burgundy-red (yellow if in shade).
'Emerald Sentinel'
30 feet tall and 12 feet wide, with a pyramid to column shape, and yellow-orange to orange fall color.
'Festival'
Narrow, columnar tree with light green leaves and fall color that is a combination of pink, yellow, peach, and burgundy.
'Gold Dust'
45 feet tall and 30 feet wide, with green leaves flecked with yellow. Fall color is pink, yellow, and burgundy.
'Golden Treasure'
Deep green leaves are edged in gold, In fall, edges turn pale yellow, then white, and the green center turns burgundy.
'Moraine'
Very cold-tolerant species of Liquidambar, to 40 feet tall and 25 feet wide, with dark green foliage and burgundy fall color.
'Palo Alto'
Orange-red to bright red fall color.
'Rotundiloba'
Rounded rather than sharply pointed leaves with fall color in yellow, red, burgundy and purple. Does not set seed.
'Slender Silhouette'
60 feet tall and just 8 feet wide, with orange-burgundy fall color.
'Variegata'
Green leaves with yellow streaks and splotches. Variegation turns pink in fall, and leaves turn red.
'Worplesdon'
Orange-red fall color.

Caring for and pruning liquidambar Trees

Liquidambar trees do best when planted in full sun to partial shade. They like to grow in moist but well-draining soil that is slightly acidic (with a pH of between 5.0 and 7.4). Trees can tolerate clay soils as well as they are well-draining and not compacted. Make sure that the installation space has enough room to accommodate the tree's full size, which can be as much as 50-75 feet tall and 40-50 feet wide. Apply a 2-4 inch layer of mulch around the base of trees to increase soil moisture retention, suppress weed growth, and regulate soil temperatures. After planting, make sure young trees receive regular waterings to help them establish a strong, healthy root system. Mature trees should be deep watered to encourage a root system that stretches farther down into the soil. Avoid overwatering these plants, as they do not like to have wet feet, and will develop root rot issues. Prune these trees in late winter or early springtime, and remove damaged, dead, diseased or crossing branches at this time to maintain a healthy shape. These trees do not need to be fertilized. A simple application of organic compost around the base of trees each year in springtime is sufficient to supply the necessary nutrients for the active growing season. If trees seem to be struggling, for example if growth is slow or leaves don't have their full color, trees may benefit from a feeding with a balanced, slow-release fertilizer in spring.

Propagation

Liquidambar can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Sweet Gum tree, follow the instructions below:

Propagating Liquidambar by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
  2. In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
  4. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Liquidambar by Seed
  1. Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
  2. Harvest your seeds. The seeds are contained inside of spiky balls which develop holes and release seeds into the environment. This process happens in fall. The balls will begin to fall from the tree and litter the ground. Collect them and place them in a paper bag. Place the paper bag in a cool, dry, dark area while the rest of the seeds are released (shaking the bag can help this process move a little faster). Once seeds are out of the balls, they can be worked with.
  3. Seeds need to undergo a period of cold stratification to germinate. To complete this process, place harvested seeds in a damp mixture of sand and potting mix in a sealable container or plastic bag, and place the container in the refrigerator for at least three months' time. Remove the seeds from their bed after the cold stratification period, and soak them in lukewarm water for between 12 and 24 hours. Viable seeds will sink, and any that float can be discarded, as they will not germinate.
  4. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  5. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Liquidambar dried seed pods. Seeds are released through the small holes.
Seeds of liquidambar trees are small and winged.

Problems and Pests

These trees can cause a litter nuisance in the garden, especially if they are planted as street trees or overhanging patios, where consistent cleanup is required. Other than the issues they themselves create in the landscape, Liquidambar trees are susceptible to developing problems with the following pests and diseases:
  • Bleeding Necrosis
  • Fall Webworm
  • Leaf Miner
  • Scale Insects
  • Tent Caterpillars
  • Glassywing Sharpshooter
  • Fungal Leaf Spot
  • Bacterial Scorch
Find out more information about these pests and diseases by consulting the following links:
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Gallery

The fall color of Sweet Gum trees is spectacular.
These are commonly cultivated street trees.
These trees stand out in the landscape, and have the potential to get quite large.
These are great shade trees for lawns and parks.
Trees produce green leaves that remain on the tree until fall, when they turn brilliant colors.
Seed pods stay on the tree for a long while, and are typically how many people identify Liquidambar trees.

Videos

Learn all you need to know about these popular landscape trees.
All about Sweetgum.
Learn about American Sweetgum trees.
These trees have the potential to get very large.

Resources

Liquidambar - Growing Guide
How to Grow a Sweetgum Tree
Propagating Your Sweetgum: Step-By-Step Guide
How to Grow and Care for Sweetgum Trees
Care Guide for the Liquidambar Bonsai Tree (Gum Tree)
Wikipedia: Liquidambar
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 416 - 417, Liquidambar (Sweet Gum)
If you have any questions, comments, concerns, or photos you’d like to add to the gallery, please let me know by sending me a message using the button below!
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