Shotgun Fungus: Stubborn Sticky Dots on the Exterior of your Home

Shotgun fungus, also known as artillery fungus, grows on organic materials, such as mulch or wood chips, and can cause small black or brown spore masses to be ejected onto nearby surfaces. The spore masses resemble tiny, sticky dots and can adhere to various surfaces, including siding, windows, cars, and other nearby objects.

The name "shotgun fungus" comes from the way the spore masses are expelled. When conditions are right, the fungus forcefully shoots its spores into the air, resembling the spray pattern of a shotgun.

The spore masses of shotgun fungus are sticky and can be extremely difficult to remove. Once they adhere to surfaces, they can be challenging to clean and may leave behind stains or discoloration. The spores are also known to be especially difficult to remove from vinyl siding.

Shotgun fungus thrives in moist environments, particularly in mulch or wood chip beds that are kept constantly moist or have poor drainage. It typically prefers decaying organic matter as its food source.

Preventing shotgun fungus can be challenging, but there are some measures you can take to minimize its occurrence:

  • Avoid using mulch or wood chips that are heavily infested with shotgun fungus. Inspect the mulch before applying it to your garden or landscape.

  • Maintain proper drainage in mulch beds to prevent excessive moisture buildup.

  • Increase the distance between the mulch or wood chips and nearby surfaces, such as siding or windows.

  • Regularly rake or turn the mulch to disrupt the growth of the fungus and expose it to sunlight, which can help inhibit its development.

If you notice shotgun fungus on your siding or other surfaces, it is recommended to clean it as soon as possible. Be cautious when cleaning to avoid spreading the spores further.

As a professional pressure washer, I can certainly help to identify and (hopefully) clean away the fungus, if it is fresh and hasn’t set in it. However, due to its stubborn nature and its tendency to stain, it is unlikely that the affected surface can be fully cleaned with a basic house wash.

It's important to note that preventing and managing shotgun fungus can be challenging, and complete eradication may be difficult. If you are dealing with persistent or severe infestations, it may be beneficial to consult with a professional landscaper or fungus specialist for further guidance and treatment options.