The HVX virus: A hidden threat to your hostas
Two years ago, I noticed a strange mottling on the leaves of one of my cherished hostas. Last year, it became worrisome and I started asking myself: could it be infected with HVX?
If you’re a shade gardener who grows hostas, it’s important to be aware of the HVX virus. Hosta Virus X, or HVX, is a serious issue that can affect the health and beauty of your hosta plants. In this blog post, we’ll examine what HVX is, how to identify it, how I diagnosed an infected specimen, and what you can do to prevent its spread.
What is HVX?
Hosta Virus X is a virus that specifically affects hosta plants, and only hostas. It is part of the Potexvirus family and is known to cause a variety of unsightly symptoms in infected hostas. It was first identified in the mid-1990s. The American Hosta Society became more concerned of its spread 10 years later when it started providing funds for research and awareness. Most growers and serious gardeners now consider that a large percentage of hostas, in private collections or available commercially, are infected in the US and Canada, some cultivars more susceptible than others.
The virus is mainly spread during propagation and through the use of infected gardening tools, unsafe cultural practices or sap contact. HVX can impact the overall health of hostas and significantly reduce their aesthetic appeal. No chemical treatment is successful.
Identifying HVX symptoms
Recognizing HVX symptoms is essential for early intervention, even if leaves may be asymptomatic while the virus is present, Here are some common signs that your hostas may be infected:
- Mottled leaves: Infected hostas often display irregular, textural mottling or streaking on their leaves. These streaks can be yellow, light green, or dark green. Color changes in the leaf pigmentation appear as mosaic, circular, color break or “ink-bleed” (localized discoloration along the leaf veins) patterns.
- Stunted growth: HVX-infected hostas may exhibit stunted growth and have a weakened or unusual appearance compared to healthy plants.
- Twisting and deformation: The leaves of affected hostas can become distorted and twisted, making them look unattractive.
- Ring patterns: Circular or ring-like patterns on the leaves can be a telltale sign of HVX infection.
- Reduced vigor: Infected hostas may exhibit poor growth and reduced overall vigor, making them more susceptible to other diseases and stress factors.
HVX showing up in my own garden
As stated above, I started noticing in 2021 something was wrong with the texture and pattern of my beautiful and very large Hosta ‘Atlantis’ bought as a small plant two years before in the nursery section of a big hardware store close to where I live. I was not really aware at the time of what HVX was, despite the fact of having hundreds of hostas in my shade borders and more than 50 varieties. Following the American Hosta Society on Facebook made me realize the symptoms were maybe caused by HVX.
To be sure my specimen was infected, I started researching the subject. I also joined the Hosta Diseases and Pests Group on Facebook to learn more. I immediately began to take precautions to prevent the potential spread of the virus.
Far left, Hosta ‘Atlantis’ in 2020, without any symptoms.
In 2022, it became clear the plant was exhibiting a stranger growth behavior. But there were may other hostas that had suffered during the summer heat and were displaying somewhat a similar behavior, so there was still hope.
However, it wasn’t until this year that I was more sure of what I had feared as the hosta exhibited more mottling, ink bleeding between the contrasting colors and a general aspect typical of a virosed plant. Despite my best efforts to isolate the affected hosta and monitor the situation closely, the diagnosis was undeniable, particularly when I shared the photo with experts. Members of the Facebook group even told me that most ‘Atlantis’ sold commercially are infected.
The only way to confirm an HVX infection is to use testing strips. These are quite expensive here in Canada. As my diagnosis is obvious, I do not see the need to proceed with testing. Serious collectors, fearing for the sake of their plants, may decide to test. Hostas are mostly used in my ornamental shade borders. Although I really enjoy all the different cultivars, I am not planning to test all my specimens on a large scale.
However, this unfortunate experience highlighted the importance of vigilance and early intervention in managing HVX and served as a reminder of the necessity of staying proactive in safeguarding the health of my hosta garden.
I made the decision of leaving the infected ‘Atlantis’ plant in the garden during this past summer, mostly for educational purposes. The leaves were not touching any other hosta. And no other plants are showing similar symptoms. Not yet anyway! The numerous visitors of my garden visualized first hand the aesthetic damages HVX does to a hosta. It may have been the most photographed plant in my garden, despite hundreds of other perennials in bloom!
I will remove the infected plant this week. No compost for the resulting organic material and soil: it will all go into the garbage bin.
Preventing HVX spread
Prevention is key to managing HVX and protecting your hosta plants. Here are some steps you can take to minimize the risk of HVX infection:
- Purchase healthy plants: Buy hostas from reputable nurseries to ensure they are free from HVX. Avoid buying hostas from some big box stores acquiring their stock from sources with disputable cultural practices.
- Isolate new plants: Quarantine new hosta plants for several weeks before introducing them to your garden. This allows you to observe them for signs of infection. But beware the plants may not exhibit symptoms for a few years.
- Practice good sanitation: Keep your gardening tools clean and disinfected to prevent the inadvertent spread of the virus. Tools used on infected plants should not be used on healthy ones without thorough cleaning.
- Remove infected plants: If you suspect an HVX infection, it’s best to remove the affected hosta to prevent further spread. Be sure to remove and destroy the entire plant, including the root system. Do not replant hostas at the same spot for a few years.
- Monitor your garden: Regularly inspect your hosta plants for any signs of HVX infection and take prompt action if you spot any symptoms. Learn to distinguish between weather-induced stress-related or seasonal changes versus HVX-related changes.
In conclusion, HVX is a potential threat to your hosta garden. With awareness and proper care, you can minimize the risk and maintain healthy, beautiful hosta plants. Keep a watchful eye on your garden, practice good sanitation, learn to recognize the symptoms, and take action promptly if you suspect any HVX infections. By doing so, you can ensure your hostas thrive and continue to be a stunning addition to your landscape.
To learn more about HVX:
- HVX Brochure by the American Hosta Society (2013)
- Hosta Virus X, by the University of Illinois Extension
- Hosta Diseases and Pests, Facebook Group
