Garden Variety: Watch for diseases when planting popular hostas
photo by: Jennifer Smith/Contributed Photo
Hostas are one of the most popular landscape plants in the U.S., known and loved for their shade tolerance, wide array of colors and sizes, and low maintenance requirements. Although they have few pest problems, the plants are susceptible to a disease known as Hosta Virus X (HVX) and gardeners should be on the lookout for it.
HVX is specific to hostas, so there is no concern about infecting other plants, animals, etc. But hostas infected with the virus may eventually die from the disease or die from other factors because they are weakened by the disease. Infected plants should be rogued from the landscape and removed from sale to avoid further spread of the disease.
HVX is identified by blotchy coloration on the leaves or color bleeding – when varying coloration bleeds across the leaf veins, mottling, puckering, twisting, brown spots, stunting and otherwise odd or unhealthy-looking plants. Many varieties of hostas have natural variegation, so it is important to know how the plant is supposed to look.
Plants in the landscape that are believed to be infected can be examined and/or tested by county extension agents and Master Gardeners through local county K-State Research and Extension offices. Samples can also be submitted to the Plant Diagnostic Laboratory that is operated by K-State Research and Extension.
Infected plants should be removed and destroyed. Clean digging tools and avoid handling healthy plants. The only ways the virus is known to spread is through propagation (division of plants) and from the movement of sap from an infected plant to a healthy one which can occur in handling or from tools.
HVX proliferated in the 1990s when many infected plants were sold that were believed to be new unique cultivars. Once the disease was defined in 1996, many growers have worked to change their practices to eliminate further spread of the disease. Difficulties in eradicating HVX include lack of recognition of symptoms by greenhouse and nursery workers, lack of symptoms in infected plants until plants are a few years old, and large-scale production of hostas worldwide.
Hostas are susceptible to a few other plant viruses, but they are less common in hostas than HVX. The Plant Diagnostic Lab through K-State Research and Extension can help identify the other viruses if plants exhibit odd growth symptoms but test negative for HVX. A few of the other viruses that can affect hostas are Tomato Ringspot Virus, Tobacco Rattle Virus, Impatiens Necrotic Spot Virus, and Cucumber Mosaic Virus. These viruses are widespread in the U.S., have a wide host range, and are most commonly moved through propagation of infected plants.
— Jennifer Smith is a former horticulture extension agent for K-State Research and Extension and horticulturist for Lawrence Parks and Recreation.