Clint Nichols, conservator of forest and shoreline resources for the Jackson Soil and Water Conservation District, reported poison hemlock along the Bear Creek Greenway in Ashland on Monday. [Jamie Lusch / Mail Tribune]
The poisonous hemlock, seen along the Bear Creek Greenway in Ashland, has found favorable conditions for its growth this year. [Jamie Lusch / Mail Tribune]
According to Clint Nichols of the Jackson Soil and Water Conservation District, purple spots on the stem of poison hemlock can help identify it apart from similar-looking plants in the area. [Jamie Lusch / Mail Tribune]
Spring rain falling on the Almeda fire scar spurred a bumper crop of harmless-looking but highly poisonous hemlock blossoms.
“With the Almeda fire, we just had a pretty significant ecological reset,” said Greg Stabach, program manager for natural resources staff at the Rogue Valley Council of Governments.
Stabach said he’s worked in Rogue Valley for 20 years and always cared for hemlock, but this year’s conditions have created a unique expansion of the invasive species. In disturbed areas, such as construction areas, recreation areas or the fire scar, invasive species take hold quickly, Stabach said, referring to hemlock as “an early colonizer.”
The plant that poisoned Socrates is native to the Mediterranean and thrives in the climate of southern Oregon. Hemlock is particularly well established in the riparian corridor—the ecological belt connected to Bear Creek.
“Near any unmanaged creek in southern Oregon there will likely be hemlock,” said Clint Nichols, conservator of forest and riparian resources for the Jackson Soil and Water Conservation District.
A small amount can be fatal to humans and animals. KEZI 9 news reported that a family cat in Veneta was paralyzed and had to be euthanized after taking a nap in a patch of hemlock that had grown in the family’s yard without their knowledge. The family identified him after one brushed against him and developed a rash.
A member of the carrot family, hemlock sports frilly leaves and flowers that resemble Queen Anne’s lace, but hemlock is taller. Mature plants are 6 to 8 feet tall with hollow, bamboo-like stems.
“The telltale signs of any poison hemlock will be purplish-red spots — almost like bruises — up and down the stem,” Nichols said.
There are two varieties of hemlock, Nichols explained, water hemlock and poison hemlock.
“The irony is that water hemlock is deadly; poison hemlock is poisonous,” Nichols said. “That’s the joy of common names.”
Water hemlock is relatively rare in southern Oregon, Nichols said, and he advises people to simply avoid anything resembling hemlock.
Stabach said various organizations came together to try and ward off invasive weeds such as hemlock for a long time, but until the Almeda fire there wasn’t enough funding or human labor to do so. more than attacking small separate areas. Funding and a sense of urgency after the fire prompted a concerted effort, but work was still too slow to keep invasive species out.
Agencies first had to respond to safety issues such as dead trees and possible ground contaminants. Next, crews examined the damage and began replacing native plants. By then, invasive species had already colonized the area.
Carl Strauss, who runs a small weed control and habitat restoration business, said he works on hemlock in the winter when the plants have started sprouting and are small. To avoid touching them, he uses small amounts of carefully chosen herbicide.
“Even in areas where I’ve worked a lot, new hemlocks have come up,” Strauss said of this year.
Each plant produces hundreds of seeds, Strauss said. Bear Creek carries them downstream, and the seeds can stay in the ground for more than five years before germinating. Usually, work of this type is only done on public land, but hemlock does not distinguish between public and private land as it grows.
Strauss advises landowners to use a shovel and remove the roots, if the plants are few and someone is uncomfortable with herbicides. For those who use herbicides, Strauss said less is a lot and anyone near waterways needs EPA-approved aquatic products.
Nichols said never to burn or compost the plant. Anyone who attempts to remove it with a lawnmower or cut it must use a mask because cutting the hemlock aerosolizes the toxin.
“It’s going to take many years of concerted effort,” Strauss said of eliminating noxious weeds from Rogue Valley.
Contact Morgan Rothborne, Mail Tribune reporter, at [email protected] or 541-776-4487. Follow her on Twitter @MRothborne.