| Event date | 2026-06-28 to 2026-07-13 (Arden Hills suspected June 28, DNR-confirmed July 7; White Bear Township suspected July 8, DNR-confirmed July 13 per the county release) |
|---|---|
| Source published | July 9, 2026 |
| Where it applies | Ramsey County, Minnesota (direct). The prevention advice applies wherever gardeners bring in bulk mulch, compost or shared plants. |
| What to do | Action needed if you took wood mulch or compost from a Ramsey County yard waste site this season: inspect it and your beds, and contact the Minnesota DNR if you find jumping worms. Everyone else: no urgent action, but use the buying and plant-checking steps below. |
If you collected wood mulch or compost from a Ramsey County, Minnesota, yard waste site this season, inspect it and the beds you spread it on for jumping worms. In July 2026 the Minnesota Department of Natural Resources (DNR) confirmed the invasive worms at the county's Arden Hills and White Bear Township yard waste sites, and the county removed wood mulch and compost from all of its yard waste sites until further notice (Ramsey County).
Key facts
- Arden Hills site: worms suspected on June 28, 2026, and confirmed by the DNR on July 7
- White Bear Township site: worms suspected on July 8 and, according to the county, confirmed by the DNR on July 13
- Where: Ramsey County, Minnesota yard waste sites
- Status: the county's jumping worms page says wood mulch and compost are unavailable at all county yard waste sites until further notice, and the sites no longer accept dirt or sod
What happened
Ramsey County paused mulch distribution at Arden Hills on June 28 and stopped compost service there on July 7, when the DNR confirmed the worms. The wood mulch from that site was hauled away to be ground and burned at high temperatures. After staff found suspected worms at White Bear Township on July 8, the county removed mulch and compost from every one of its yard waste sites. It asks residents who took either material home to check it and their yard or garden, and to contact the Minnesota DNR if they find jumping worms (Ramsey County).
How to recognize jumping worms
Penn State Extension describes three signs (Penn State Extension):
- Behavior: when you scratch the topsoil, they thrash with an erratic, snakelike movement. Ramsey County describes them as wiggling intensely and seeming to jump when disturbed. They can grow to about 6 inches.
- Band: the clitellum (the band near the head) is milky white to light gray, completely encircles the body and sits flush with it. On European nightcrawlers it is raised, reddish-brown and does not wrap all the way around.
- Soil: the surface turns uniform and granular, often compared to coffee grounds.
Jumping worms are an annual species: adults die at the first freeze. Their cocoons, about the size of a mustard seed, survive the winter and hatch in spring once temperatures have stayed around 50°F for a while. One worm can produce many cocoons without mating, and because the cocoons are so small they travel easily in compost, bark and leaf mulch, and in the soil around shared plants.
What to do
- If you took county mulch or compost: look through the pile and the beds it went on for thrashing worms or coffee-ground-textured soil. If you find jumping worms, contact the Minnesota DNR, as the county asks.
- Don't pass it on. Ramsey County advises against moving dirt, sod, mulch or compost, because that can spread the worms. The same goes for divided plants from a bed you suspect is infested. For disposal questions, the county's jumping worms page lists 651-633-EASY (3279).
- Buy bulk mulch or compost from a reputable producer that heat-treats it. Penn State Extension's benchmark is at least 130°F for at least three days. Bagged mulch is the alternative it suggests.
- Check plants before planting. If a pot shows the coffee-ground texture, discard the plant, or remove all the soil and rinse the roots thoroughly.
- For small infestations, Penn State suggests handpicking adults, bagging them and putting them in the trash. It also describes a mustard-and-water drench that brings adults to the surface so they are easier to collect. To kill cocoons, it suggests covering moist soil with clear plastic for two to three weeks, until the soil has stayed above 104°F for at least three days.
Removing adults alone won't clear an infestation, because the cocoons carry it into next year.
Why this matters for your garden
Compost and mulch improve soil, but bulk material can also carry jumping worm cocoons into a garden, as this case shows. Knowing where your organic matter comes from, and whether it was heat-treated, matters as much as how much you use. For handling compost at home, see how to store finished compost and the best ratio of compost to soil.