Artillery fungus, also known as shotgun fungus (Sphaerobolus spp.), is a nuisance for homeowners and landscapers alike. This small, wood-decay fungus is notorious for its ability to shoot tiny, sticky spore masses up to 20 feet away, leaving stubborn black spots on siding, cars, windows, and anything nearby. These spots are difficult to remove and can cause permanent staining, making artillery fungus a frustrating issue in residential and commercial landscapes.
Artillery fungus thrives in moist, organic materials, particularly hardwood mulch, where it breaks down decomposing wood. It tends to be most active in cool, damp conditions, often in the spring and fall. Unfortunately, once the fungus is present and its spores attach to surfaces, they can be incredibly hard to remove without damaging the underlying material.
So what can you do if you encounter artillery fungus? First, prevention is key. Consider using non-organic mulches like stone, gravel, or rubber mulch in problem areas. If you prefer organic mulch, pine bark, pine straw, and cedar mulch are less likely to host the fungus compared to hardwood varieties. Keeping mulch layers thin — around two to three inches — and ensuring proper drainage can also reduce moisture levels that encourage fungal growth.
If you already have artillery fungus, replacing the affected mulch with fresh, fungus-free material can help curb the spread. Power washing or using a mild cleaning solution may remove some of the spores from surfaces, but be careful to avoid damage. In extreme cases, repainting or replacing stained surfaces may be the only way to fully eliminate the black spots.
By choosing the right mulch and maintaining good landscape practices, you can reduce the risk of artillery fungus and keep your outdoor spaces looking their best. With a little attention to detail, you’ll minimize the chances of this pesky fungus taking hold.