By Nora Saks
Last summer, Maine state horticulturist Gary Fish found himself fielding calls from distraught gardeners. “I’d pick up the phone, and they’d be crying, worried their gardens were going to be devastated,” Fish says. Behind the tears, invariably, were infestations of invertebrates that closely resemble common earthworms — except that, instead of squirming slowly away when disturbed, they hurl themselves into the air and thrash about wildly. Fish knew these worms weren’t an isolated issue and realized the season was going to be particularly bad. “The jumping worms were out of control,” he says, “and the people were out of control.”
Jumping worms — also known as crazy worms, snake worms, and Alabama jumpers, among other sobriquets — are native to East Asia. Like many other invasive species in North America, they probably traveled across the ocean in shipments of plants and other horticultural supplies in the 19th century. They’re hardly new to Maine, first spotted in a Waterville greenhouse in 1952. Suddenly, though, they seem to be thriving. In 2014, several established populations were discovered for the first time, at Augusta’s Viles Arboretum and in two Portland gardens. Soon, officials at the Maine Department of Agriculture, Conservation & Forestry began sounding the alarm.
“The problem is that jumping worms are nutrient hogs,” Fish says. Fast growers and voracious eaters, they devour any and all organic matter — compost, mulch, leaf litter — and leave behind depleted, granular dirt the texture of yesterday’s coffee grounds. That disruption to the soil makes it harder for plants to thrive in gardens and farm fields. The threat to forests, especially hardwoods, is worse. Over the years, Fish has watched as the roots of green ash trees at the Viles Arboretum, across from his office, have become steadily exposed and typical forest understory has been replaced by grasses. As the earthworms gobble up the top few inches of the forest floor, nutrients and moisture are stripped away, native biodiversity decreases, and erosion increases, causing a cascade of harm to woods and to waterways.
At a glance, a jumping worm looks a lot like the common earthworm (which itself is a nonnative species, brought over from Europe hundreds of years ago — long after the last glaciation eliminated any native worms). But upon closer inspection, aside from the jumping worms’ herky-jerky conniptions, there are a few other subtle differences between mature worms (juveniles are much harder to distinguish). On jumping worms, the cl*tellum — the milky-white reproductive gland — is smooth and close to the head, and it completely encircles the body. On common earthworms, it sits like a saddle more toward the middle of the body. Plus, when threatened, jumping worms often drop segments of their tail to escape.
They’ve now been detected in 13 out of 16 counties (and a majority of U.S. states), “and we know that pretty much all of southern Maine is infested with them,” Fish says. In 2023, the number of confirmed reports in the state leapt tenfold. In part, more farmers and gardeners know to look for them now, but Fish suspects the wet summer might have especially helped their populations flourish last year. Milder winters could be a factor too. Though a hard frost usually kills off adults, their tiny egg-filled cocoons can survive in the soil before hatching out in late spring.
Now that the subterranean dwellers have wormed their way into an ecosystem, they’re almost certainly here to stay. “Unfortunately, there are still no well-researched and efficacious methods to control them,” Fish says. State officials are primarily concerned with trying to prevent, or at least slow, their spread, especially into Maine’s vast forests. The Department of Agriculture, Conservation & Forestry recommends growers buy or swap only bare-root plants, thoroughly clean tools and boots, and refrain from moving soil or compost on or off their property. Beyond that, Fish has adopted a sort of zen attitude toward the worms, which he tries to impress on gardeners who call him up in a tizzy. “My feeling,” he says, “is that you shouldn’t worry a whole lot about something you can’t do much about.”
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