AgEBB-MU CAFNR Extension

Forrest Rose
Information Specialist

March 15, 2004

Yearly expense, effort sours
Homeowners on sweetgum trees

COLUMBIA, Mo. – 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,” a University of Missouri horticulturist said.

“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?’” said Chris Starbuck, MU extension woody ornamentals specialist. When the callers were told there was no guaranteed gum-ball prevention technique, he said, “chain saws could sometimes be heard starting in the background.”

Several chemical controls for sweetgum have been introduced recently, Starbuck said. Florel Fruit Eliminator, which uses a traditional growth regulator employed in greenhouses, can be sprayed on flowers to prevent fruiting. 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.

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, and it also has a narrow time window for effectiveness.

“It may be challenging to spray to the top of a large tree,” Starbuck said. “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.”

The effort and expense involved might not be worth it to some sweetgum owners, he said. “Many people become discouraged when they find that they might have an annual cost of about $200 to use either of the treatments available for a large tree.”

Those who do opt for treatment might have other concerns, Starbuck said. “Neither of these products have characteristics that I consider very dangerous compared to oven cleaners, ant sprays and many other things we use around the house. I do, however, wonder about the effects of the spray drift from spraying a large sweetgum with Florel.

“My concern is primarily that there may be unintended effects on unintentionally sprayed plants,” he said. “The material itself will probably be converted by sunlight and microbes to carbon dioxide and water within a day or two after it has done its job.”

There is a fruitless sweetgum tree cultivar, Liquidambar styraciflua rotundiloba, that has “a little bit different leaf shape,” Starbuck said. The cultivar from North Carolina generally has thrived in more southerly locales, but “several of these have been planted at Missouri Botanical Garden, and there’s a good chance that it’s hardy enough for this zone. They have the same growth habit and same nice 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, he said. “They don’t make the most attractive mulch, but they do make sort of a barrier for rabbits and other critters. It pricks their feet, and they don’t like it.”

Sweetgum balls are also said to be good fire starters that burn with a blue flame, Starbuck said. “Why spend all that money on fancy stuff to start your fire? Just use some of those sweetgum balls.” He added a word of caution for those who go out to gather the prickly spheres: “Be sure to wear your work boots.”

Source: Chris Starbuck (573) 882-9630

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