Question
My name is Rich and I live in the Philadelphia suburbs. I have a 25-30 year old sweet gum that flowers thousands of those dreaded gum balls every spring, fall and every other day. They ruin my grass. The tree sits 40-50 feet tall. Can I top this tree or heavily prune the tree to at least cut down on the flowing.  Also, I can get on my roof and spray it with a hose with a product to stop the seeding. Before I purchase, however, the information states that the tree must be sprayed at the appropriate time of year. When is that for the sweet gum, how much product would I need, and will it actually work?.  Can I spray it in conjunction with a heavy prunning?  

Answer
These "balls' are the fruit of the sweetgum. Pruning will not help since the flowers are formed on new growth and pruning will stimulate new growth. Topping will not help and may even cause the tree to die and will make it look bad.

There are chemicals but as you said timing is the thing--usually the flowers will be formed as the new leaves are budding out and this would be the time to spray but all the foliage would need to be sprayed each year to stop fruit production.


There really isn't a practical solution for completely preventing fruit on large, well-established trees, but there are some hormone-based products that can help reduce fruit set. One such product is ethephon, sold as Florel Brand Fruit Eliminator? It must be applied at just the right dosage, at just the right stage of flowering (full bloom) and at just the right temperature range. There is risk of plant damage if dosage and/or temperature are too high. In fact, plant stress of any kind can increase the likelihood of plant damage. And, because the product must be sprayed on, the effectiveness will depend on being able to get complete coverage of the canopy, not an easy task on a large, mature tree.


There is another product called Snipper?that is designed to be injected into the tree while the flowers are still in bud stage. However, the application uses a micro-injection system that requires skilled precision. Like other hormone treatments, timing and dosage are critical. This product should only be applied by a professional.


You might want to contact a certified arborist for estimates on both of these methods. The price of fruit prevention might make sweet gum fruit cleanup a bit easier to accept!