On a mild spring day in 1980, a handful of men gathered on the sprawling lawn of England’s Windsor Castle, there to do a little landscaping. And one of them brought a silver-plated shovel.

The man stuck the spade into the ground to dig a hole for an elm tree. The laborer was, in fact, British royalty – Prince Philip, husband of Queen Elizabeth II. His simple act was part of a broader campaign to save the elm from widespread annihilation carried by a diminutive insect.

Accompanying Prince Philip that day was Eugene Smalley, a professor of plant pathology at UW-Madison who had been tasked with fighting the spread of Dutch elm disease (DED) two decades earlier. Smalley and the prince chatted congenially as a press pool snapped photos.

Prince Philip plants the elm developed by Eugene Smalley (right). Photo: Fox Photos LTD.

First identified in the Netherlands in 1919, DED quickly spread through Europe via elm bark beetles before arriving in the United States in 1930. Since then, more than 50 million American elm trees have been felled. The towering Ulmus americana had once blanketed the United States and stood as an elegant staple along avenues in communities across much of the U.S.

“The American elm tree has had a unique niche in American life,” Smalley told The New York Times in 1989. “Before the disease, you could find streets lined with elms in almost every American town.”

Ray Guries, a professor emeritus in the UW-Madison Department of Forest and Wildlife Ecology and former associate of Smalley’s, called the rapid decline of the American elm a “traumatic experience” for residents of urban areas. “When they disappeared, it was as though an icon had been lost.”

Early efforts to halt the spread of Dutch elm disease were ineffective. Stopgap measures included pouring Epsom salt on tree roots, hammering aluminum nails into the bark and even burying aspirin tablets in the surrounding soil.

Smalley was hired by UW-Madison in 1957 as part of a state legislative appropriation aimed at saving Wisconsin’s elm trees. With his background in plant pathology, he immediately went to work planting elm seedlings on the Arlington Agricultural Research Station north of Madison. This stand became known as “Smalley’s Elms,” and many can still be seen today when driving northbound on State Highway 51.

Smalley theorized that hybrid species with natural pest resistance—not pesticides—offered the best defense against the beetles. After 20 years of research, Smalley and his colleagues produced several candidates with the potential to replace the once-ubiquitous American elm. Hybrids known as Regal, American Liberty, New Horizon and Cathedral all proved to be hardy against the cold and generally resistant to DED.

The elm tree as it stands today on the grounds of Windsor Castle. Photo: The Conservation Foundation.

Another promising hybrid was the Sapporo Autumn Gold, which was the type of tree that Prince Philip set into the ground in 1980. The modest tree planted that day at Windsor Castle represents a glimmer of hope – it still stands and has since propagated more than 100 other elm trees on the property.

Smalley died in 2002, but his legacy lives on in his life’s work and the trees he planted. His disease-resistant elms have replaced those that have died on the UW-Madison campus, at the Wisconsin State Capitol Park, at Harvard University, in London’s Hyde Park, along the Rhine River in Germany and elsewhere.

Even the embattled American elm may be bouncing back. Guries has spotted them being planted once again in Madison. Though it’s unlikely to ever reclaim its former status, the tree and its hybrid cousins stand as a testament to Smalley’s research in an effort that plays out over decades.

“In developing the right tree, we don’t deal in years,” Smalley once told the Wisconsin State Journal. “We deal in generations.”