In fact, if you wish to grow the species plant because you enjoy crafts and can make use of the gumballs, the best location for the tree is far away from the house and any outdoor areas where people will be walking (people have been known to sprain their ankles from walking on the gumballs). For those with large properties, one option may be to plant their sweetgum tree on the south side of a woodland garden. Thus located, you will not have to bother with the landscape maintenance required to clean up the fallen gumballs.
Light
One thing American sweetgum is not tolerant of is shade, so be sure to select a spot in full sun for it.
Soil
Although American sweetgum tolerates clayey soil, give it a well-drained loam for optimal performance. It will also prosper the most in deep soil. It does not like alkaline soil.
Water
Keep the soil of American sweetgum evenly moist, at least until it has been established for a few years.
Temperature and Humidity
As a tree native to areas such as Florida, American sweetgum tolerates heat and humidity well. But it isn’t reliably cold-hardy north of zone 5.
Fertilizer
Because American sweetgum is not a heavy feeder, you only need to fertilize it once every few years. Fertilize with compost, manure tea, or an all-purpose fertilizer.
Types of Sweetgum Trees
The Liquidambar genus contains a few other species besides styraciflua, as well as cultivars other than ‘Rotundiloba,’ including:
Liquidambar formosana: more drought-tolerant than most sweetgums; 40 to 60 feet tall and wide; zones 6 to 9 Liquidambar acalycina ‘Burgundy Flush’: burgundy-purple-bronze leaves; 50 feet tall and 25 feet wide; zones 6 to 8 Liquidambar styraciflua ‘Slender Silhouette’: columnar shape; 50 feet tall and only about 4 feet wide; zones 5 to 8 Liquidambar styraciflua ‘Variegata’: variegated leaves streaked with yellow or off-white markings; 60 feet tall and 25 feet wide; zones 4 to 10 Liquidambar styraciflua ‘Gumball’: dwarf variety in shrub form; 5 feet by 5 feet; zones 5 to 8
Pruning
If you must prune, as is true when dead, diseased, or damaged branches are present, the best time to do it is right after the blooming period, which is April or May. But this specimen usually doesn’t require pruning otherwise.
Propagating
American sweetgum is difficult to propagate via cuttings, which is why propagation via seed is more common. However, if you wish to try to grow a new plant by taking a cutting from a green, non-woody stem, here is how the process works:
How to Grow Sweetgum Trees From Seed
While ‘Rotundiloba’ is a non-fruiting cultivar, the species plant does reliably produce gumballs, which mature by mid-to-late autumn. The tricky part of using them for propagation is in the timing. On the one hand, green gumballs aren’t ripe. On the other hand, if you wait too long after they’ve browned, the seed can be lost. This is because, when drying is complete, tiny holes will develop on the surface of the gumball. The seeds are ejected out of these holes. The ideal time to gather them is after they have turned brown (indicating maturation) but before the fruit has totally dried. So there’s just a small window of opportunity for you to work with. You want to bring the fruit indoors to complete the drying process. A cool, dry place is ideal. Place the fruit in a shallow pan. Drying will be complete typically in 5 to 7 days. At that point, the seeds will be ejected and you can gather them. Since sweetgum seeds have a chilling requirement, insert the seeds in an envelope, and refrigerate them for 30 to 60 days. Sow the seed outdoors after all danger of frost has passed.
Overwintering
American sweetgum is cold-hardy to zone 5. You don’t need to take any measures to overwinter it unless you live north of zone 5, in which case you can protect its roots from severe winter cold through mulching.
Common Plant Diseases
The species tolerates pests (such as rabbits) quite well. But it is susceptible to some plant diseases.
Leaf Spot
The spots of the leaf spot fungal disease come in a variety of colors, shapes, and sizes. But they’re usually dark (or light with a dark border), with a rounded or irregular shape. The spots appear on top of the leaf. Leaf spot is rarely fatal, but it inhibits photosynthesis, weakening the tree and rendering it more susceptible to other plant diseases. Leaf spot is best controlled by taking preventive steps:
Avoid late-evening watering: You’re not giving the sunlight a chance to dry the plant’s foliage before night falls. The result is that moisture lingers all night, creating optimal conditions for fungal diseases. For the same reason, avoid irrigating from above. Moistening the foliage invites fungal infestation. Irrigate at ground level.Practice sound garden hygiene. Properly dispose of diseased plants. Rake up leaves that have accumulated around plants. Promote airflow by spacing plants properly.
Chlorosis
If your American sweetgum is growing in soil that is too alkaline, it may develop a disease known as “chlorosis,” which is caused by a deficiency in the soil. Chlorosis is often signaled by leaves or leaf veins turning yellow. You will have to correct the soil deficiency to address the problem of chlorosis. Before doing so, send a sample of the soil in to your county extension office. They will specify the deficiency in your case and suggest a soil amendment as a remedy. For example, fertilizers geared to acid-loving plants are often used to lower the soil pH.
