Cooperative Extension: Garden and Yard

The solution to artillery fungus (Sphaerobolus spp.) is to remove the source of the ongoing infection–typically, mulch, compost, old wood shingle siding, any kind of decaying organic material. I would prune out heavily affected plant material (removing the deposits usually do more damage to the plant than it’s worth) and then either replace existing mulch with a more resistant choice (if this is the likely culprit) or remove the other nearby organic matter that’s serving as the source. It may take a season or two to resolve any leftover spots already present, but the fungus should be heavily mitigated by changing the environmental conditions. There are no currently registered chemical treatments.

Happy gardening.