Unexplained dirt mounds in residential lawns can often cause concern among homeowners. These piles of soil, which may appear suddenly and in clusters, are usually the result of underground activity by various animals or insects.
Several types of creatures are known to create such mounds. Moles, for instance, dig tunnels as they search for earthworms and grubs. They push dirt to the surface in round, volcano-shaped piles that typically lack an open hole on top. Homeowners may also notice raised surface trails across their lawns associated with mole activity.
Voles, also referred to as field mice, leave behind small round holes in turf along with shallow runways on the grass surface. Their mounds are less prominent than those made by moles, but the entry holes serve as a clear indicator of their presence.
In wet or low-lying areas, crawdads (crayfish) can sometimes build muddy “chimneys” with vertical holes at the center. These structures differ from other types of mounds due to their moist composition and upright shape.
Cicada killer wasps, large solitary insects active during late summer, excavate burrows that result in small loose piles of dirt next to round entry holes. While these wasps can appear intimidating due to their size, they are generally not harmful to humans.
Pocket gophers create larger fan-shaped mounds with plugged tunnels off to one side rather than an open hole on top. Their mounds often occur in clusters and can spread quickly throughout a lawn depending on geographic location.
Occasionally, rabbits or other small animals will dig shallow nests that produce loose dirt piles resembling minor mounds. However, if numerous mounds appear each week, rabbits are unlikely to be responsible.
Identifying the specific animal or insect responsible involves observing details such as mound shape, presence or absence of visible holes, signs like raised trails or mud chimneys, and the timing of appearance—cicada killers tend to be active only in late summer while others may be present year-round.
Effective responses depend on identifying the source:
- Traps are commonly used for moles and voles.
- Improving drainage is recommended when crawdads are present.
- Cicada killer wasps typically require no action unless they become a nuisance.
- Gopher control may involve trapping or baiting according to local regulations.
- Rabbit nests should be relocated carefully if found.
If attempts at home remedies do not resolve recurring issues with dirt mounds or if identification remains uncertain, consulting a professional lawn care provider is advised. As stated: “Not sure what’s causing the mess in your lawn? GreenPal can connect you with a local lawn pro who’s seen it all and knows how to get your yard back to normal.”