If you’ve ever been driving along the north side of Putah Creek in West Davis during late spring/early summer, you’ve probably noticed a spectacle of vibrant colors just off the road behind a research fence. Those beautiful colors belong to the roses in the FPS Rose Clean Stock Program.

The story of the Rose Clean Stock Program starts back in the 1960s with Dr. George Nyland, a plant pathologist and advocate of virus-tested planting stock. He began using heat therapy to propagate rose material free of rose mosaic disease and created a collection of...