Walt, Loved your response. LOL!! I have a gum tree I planted in my front lawn 15 years ago. Until the year before last, it behaved itself and didn't produce those dastardly gumballs. I'll let it grow this summer yet...then the chain saw gets the sucker while it's still manageable for me to drop. They're pretty trees, and the fall foliage is spectacular, but enough is enough of those damn spiked balls! To the original poster: When you get to the point of having literally bushels of these damn things to litter your lawn, garden, or street (or all three), you'll wish you had never heard of this tree. On a mature one, the root system is vast, surface disrupting too, and extremely expensive to remove if thoroughly done. Hal

It was a good year for sweet gum balls. We even tried treating our tree with Indole 3-butyric acid in hopes that it would reduce their number but it didn't. I don't think they're toxic to water lilies or fish. Have you thought about adding mosquito fish to your water garden?

There is no problem composting the leaves or wood chips from the Sweetgum, "Liquidambar styraciflua", tree. Handling the leaves and wood can, often, give that turpentine odor but it will dissipate over time.

If you can crush or shred them (gas wood chipper?) they would make a great mulch. That would also accelerate any decomposition in the compost pile.