New Hosta Disease Becoming A Serious Epidemic

When we say “new” in the world of plants, it’s often something that originated within the past 20 years, but has only recently come to the forefront. For example, a “new” plant variety might have been bred 20 years ago and took decades to test and reach the retail market.

A very serious “new” disease is affecting the popular perennial hosta. It was first identified about 20 years ago, but is now becoming a widespread and damaging epidemic, identified in most states including North Dakota and Minnesota, and many of us have only recently become aware of it.

The disease is caused by a virus, and has been termed Hosta Virus X disease, abbreviated HVX. For information about the disease, I researched North Dakota State University, University of Minnesota, Wisconsin State University and others. The most recent information I found was written by Illinois State University July 5, 2017, and much of the following information is based on that literature, supplemented by the others.

The HVX Problem: 

  • The symptoms tend to be subtle and not always easily identified.
  • Plants infected with the virus can be carriers of the disease even if they don’t show symptoms, but they can pass the disease to other hosta plants.
  • Plants infected with the virus might not show disease symptoms for a year or two.
  • Hosta plants are being sold that contain the virus disease, some showing symptoms, some not.
  • Only hosta are affected by this particular virus; it doesn’t travel to other perennials.
  • Many perennial gardens and landscapes are now harboring HVX, unbeknownst to their owners.

Symptoms of HVX Disease on Hosta Plants:

  • The virus doesn’t usually kill hosta plants, but it can.
  • Symptoms can be subtle; look for leaf patterns or markings that aren’t characteristic of the hosta variety.
  • Symptoms vary between the many different hosta cultivars.
  • Look for light or dark green discoloration along leaf veins, referred to as “ink bleed.”
  • Look for mottled yellow/green pigment, mosaic patterns, puckering, circular ring spots, necrotic dry dead leaf tissue, wilting and sometimes death.
  • Leaves are sometimes stunted and distorted.
  • Sometimes only one or two of the symptoms appear, not necessarily all of those described.
  • Overall health of the hosta plant generally declines over time.
  • Plants that are seemingly healthy can still be carrying the virus internally.
    Infected hosta showing necrotic leaf margin and mottled color
    Non-uniform leaves plus “ink bleed” pattern on veins
    Infected plant
    Mottled symptoms of HVX
    Puckering caused by virus

    Testing for virus

Where does the disease come from, and how is it spread?

  • HVX is usually introduced into an established hosta planting when new hosta plants are brought in. The new plants might be infected, but not yet showing symptoms.
  • The disease is not known to be spread by insects.
  • HVX is spread by infected sap that gets transferred between hosta plants on hands and pruning tools.
  • The disease is easily spread when hosta are divided and distributed between friends and neighbors.
  • Many retail outlets are unknowingly selling infected plants, especially mass merchandisers.

What can be done? Is there a cure or treatment?

  • Once a plant is infected, there is no cure. Infected plants should be dug and destroyed by burning or disposing in landfill.
  • When an infected hosta is removed, carefully remove all root pieces, and wait at least a year before replanting a hosta in the same spot.
  • There are no immune hosta varieties.
  • There are no chemicals that prevent or treat HVX.
  • Carefully wash and sterilize tools and hands when working with hosta.
  • Avoid sharing hosta divisions with fellow gardeners.
  • Simply removing leaves that show symptoms doesn’t work, as the virus is in the sap flowing through the entire plant.
  • Buy hosta only from reputable garden centers that might know if their stock has been virus-indexed or tested. Remember that even plants with no symptoms might be carrying HVX disease.
  • Garden centers and hosta wholesalers can test their stock to ensure it’s free of HVX, using a product called ImmunoStrips by Agdia Corporation.
  • Other than testing, there is no foolproof way of telling whether a hosta you’re purchasing is infected, unless of course, you see symptoms.
  • The disease is possibly less active in late summer and fall, when hostas are done blooming, which might be a better time to divide or transplant hosta, than spring or early summer when the virus is most active.

This disease is a serious problem because of the sheer numbers of hosta contained in perennial gardens and landscapes.

6 Responses

    1. Don Kinzler

      I’m not sure. I went to the Agdia ImmunoStrip website, but you had to sign in for prices and purchase info. I didn’t get a chance to set up a user ID, etc. So I’m not sure. It might be worth pursuing if I can find a phone number. These test strips were mentioned by a few of the universities from which I got information.

    1. Don Kinzler

      They are probably disease-free if currently healthy after 10 years. The difficult thing is that many of us would like to plant new and different varieties of hosta, and now it’s going to be difficult to know if we should add any new ones to our existing.

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