Coles County Yard and Garden

Coles County Yard and Garden

Sweet Gum Balls Are Not So Sweet

This column was written by Kathy Hummel, Coles County Master Gardener.

The first section of this column is based on information courtesy of Chris Starbuck, MU extension woody ornamentals specialist.

Their name – sweetgum balls – sounds like a tasty dessert treat, but they present an unappetizing prospect for homeowners. The spiky balls that fall from sweetgum trees can be a source of extreme annoyance, pain or bodily injury.

In the spring, extension centers get a lot of people calling to ask, "Isn't there something I can spray to keep those stupid balls from forming on my sweetgum tree?" When the callers are told there was no guaranteed gumball prevention technique, chain saws could sometimes be heard starting in the background.

Several chemical controls for sweetgum have been introduced recently. Florel Fruit Eliminator, which uses a traditional growth regulator employed in greenhouses, can be sprayed on flowers to prevent fruiting. However, there is a time window for treatment of only about one week, and Florel should not be sprayed on trees that are under stress from drought, disease or other problems. Overspray can also damage surrounding plants and auto paint.

It may be challenging to spray to the top of a large tree. For large trees or when multiple trees must be treated, it is best to retain the services of a firm with the proper equipment to do the job. Read the Florel Label

Another de-flowering agent for sweetgum trees is called Snipper, which contains a synthetic analog of a growth-regulating chemical found naturally in plants. This product must be applied via trunk injections by a professional arborist; it also has a narrow time window.

Earlier this week I spoke with the inventor of this product. He said the sweet gum tree is an unusual breed in that the buds develop in 2-3 waves, so that an application will inhibit only those flowers in the proper stage. And multiple injections would be injurious to the health of the tree. Homeowners might expect an annual cost of about $75-100 per tree to use either of the treatments. By the way, these treatments are effective on oak, walnut and gingko trees. Read the Snipper Label

There is a fruitless sweetgum tree cultivar, Liquidambar styraciflua rotundiloba. The cultivar from North Carolina generally has thrived in more southerly locales, but several of these have been planted at Missouri Botanical Garden in St. Louis, and there's a chance that it might be hardy enough for this zone. They have the crimson fall color – which is one of the nicest things about the sweetgum tree.

Those who decide simply to live with the sweetgum balls might be able to employ them for other purposes. They don't make the most attractive mulch, but they do make sort of a barrier for rabbits, slugs and other critters. It pricks their feet and tummies, and they don't like it.

Sweetgum balls are also said to be good fire starters that burn with a blue flame. Why spend all that money on fancy stuff to start your fire? Just use some of those sweetgum balls.

Other ideas: Spray sweetgum balls with silver and gold paint and hang them on the Christmas tree. Place them in a jar and sell them on eBay as PORCUPINE EGGS....


Sweetgum tree could help lessen shortage of the bird flu drug. The sweetgum tree grows widely throughout the United States, [including Illinois,] and is known for its mace-like green fruit. Now, this spiny fruit may become an important source of a chemical needed to make a lifesaving drug against bird flu - a drug that is currently in short supply worldwide, researchers say.

Chemists have found that the seeds of the sweetgum fruit contain significant amounts of shikimic acid, the starting material used to produce the main antiviral agent which blocks the replication of the flu virus.

At present, the shikimic acid is obtained almost exclusively from the Chinese star anise, a fruit that is found mainly in China and whose supply has dwindled due to high demand for the flu drug. Although shikimic acid is found in small amounts in many plants, star anise has been considered the most abundant plant source, until now.

"Our work gives the hearty sweetgum tree another purpose, one that may help to alleviate the worldwide shortage of shikimic acid," says study leader Thomas Poon, Ph.D., a professor of chemistry from the W.M. Keck Science Center at The Claremont Colleges in Claremont, Calif. "They have lots of potential for fighting bird flu."

In the mature tree, the fruit emerges as a green seedpod that later dries into a brown, spiny husk, which releases an abundance of tiny, grain-like seeds. Each tree can hold hundreds, if not thousands, of seedpods.

As enthusiastic as he is about the sweetgum tree's potential contribution to world health, Poon has a word of caution." It's the seeds that are rich in shikimic acid," he says. "And to get the seeds before they disperse, you have to get the husks while they're green. You have to harvest them when they're still hanging on the tree." There go your visions of a gumball gold mine.

Be sure to check out the U of I Extension website at for valuable information on energy conservation, gardening, nutrition and many more topics.

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