The News Desk is a collection of news, notes and breaking items affecting the Fredericksburg community.

RSS feed of this blog

Fungi to help stem riverbank’s erosion

Mushrooms have been growing along the Rappahannock River for eons, providing colorful scenery for hikers and the occasional snack for wildlife and human foragers.

But now they have another role—stemming erosion—thanks to an innovative collaboration by Fredericksburg’s waterfront property manager, and a local coffee roaster and fungi entrepreneur.

“It’s a really good solution,” Lee Sillitoe, a city police officer who manages the more than 4,200 conservation easement acres along the Rappahannock and Rapidan rivers, said in a recent interview.

Unlike other erosion-control methods, “everything you put in place, you leave, and it’s an inexpensive way to do it,” he said.

Over time, “You won’t even notice it’s there.”

One recent morning, Sillitoe and a group of volunteers gathered at Tom Spouse’s horse farm in Fauquier County. The volunteers brought 30 large coffee sacks filled with straw, and hardwood pellets inoculated with oyster mushroom mycelia—the vegetative part of fungus—grown by Ryan Mooney.

Spouse, whose farm sits near Rock Run, a tributary of the Rappahannock, was building a horse trail on his property, Sillitoe said, when he mistakenly crossed over onto city-owned easement land.

A hunter spotted the intrusion and reported it to Sillitoe, who visited the site and met with the landowner.

Spouse “was very upfront about it,” Sillitoe said, and agreed to pay for the remediation project.


Sillitoe and Kyle Orton, a student intern from Randolph–Macon College, filled the bags with the growing medium and mycelium ahead of time at Friends for the Rappahannock headquarters on Fall Hill Avenue in Fredericksburg.

Sillitoe and two helpers—David Rowan, a Marine Corps buddy from Stafford, and Woodie Walker, membership and volunteer coordinator with Friends of the Rappahannock—hauled the bags to Spouse’s farm near Skinker’s Mill.

They used a four-wheeler with a trailer to haul them down a muddy trail through the woods to the dug-out spot on the creek.

“He [Spouse] tried to do a crossing here,” Sillitoe said, pointing to a rectangular hole along the creek bank.

Sillitoe lifted one bag to reveal a white sheen of tiny fungus filaments growing through it.

Within months they produced “a great, aggressive root structure to hold dirt and keep the bank in place,” Sillitoe said, providing a natural solution to an age-old problem.

The bags are biodegradable and eventually decompose, becoming part of the landscape.

The bags were stacked with straw between each layer to keep the growing mycelia moist. The mound was held in place with stakes of bamboo, an invasive species cut from another section of city-owned land along the river.

Water-loving willow oak and sycamore seedlings will be planted among the bags this spring to permanently hold the soil in place.


Sillitoe and Mooney met a couple years ago at a Blackstone Coffee store in Spotsylvania County, and soon found areas of mutual interest.

Sillitoe was looking for more environment-friendly ways to deal with erosion issue on the city land. Mooney had a longtime interest in mycology—the science of fungi—and was growing oyster and shiitake mushrooms for a local eatery.

“I was reading a book at the time, ‘Mycelium Running: How Mushrooms Can Save the World,’” Mooney said. The book, by West Coast mycologist Paul Stamets, includes a section on fungi’s potential as an erosion-mediation tool.

“Ryan was the one who brought me into this,” recommending he check out the book, Stamets’ website, and other sources online, Sillitoe said.

Soon, Sillitoe and Mooney were talking about real-world applications.

Their first attempt at fungi remediation was two years ago off Richards Ferry Road, above where the Rappahannock and Rapidan rivers join in Culpeper County.

They were attempting to repair an area where three men on a weekend camping trip got their truck stuck on city land, then got a bucket loader stuck while trying to get the truck out. The escapade tore up the river bank in the process, and was so egregious, the perpetrators wound up in court.


Mooney collected wild oyster mushrooms, cultured them in his home laboratory, mixing the mycelia with a sawdust-and-straw growing medium.

That was spread with dump trucks and loaders, and it worked, Sillitoe said.

But they needed a simpler method, “something with less impact on the environment” that could be done with a few volunteers, without heavy equipment, he said.

Sillitoe wondered whether coffee-shipping bags used by Mooney for roasting would work.

“Ryan went to a roasting convention and talked to guys with [Chesapeake Bay Roasting Co],” Sillitoe recalled. The company donated a load of bags after hearing about their plans.

With the coffee bags in hand, the duo decided to upgrade the growing medium, from sawdust to hardwood pellets and straw.

Mooney charges $15 for 5 pounds of the mushroom culture, enough for one bag.

Sillitoe hopes to use them on other spots along the river.

“You can stack these on the back of a truck or an [all-terrain vehicle], and one person can put them in place.”

Rusty Dennen: 540/374-5431