Hosta virus X
Hosta virus X potexvirus
also called HVX
Ink-bleed mottling that follows the veins of a hosta leaf, spread almost entirely by sap on tools. Some of it was sold deliberately as a variegation.
What you'll see
- Blue-green or dark mottling bleeding out along the veins, like ink drawn into wet paper.
- Puckered, lumpy or dimpled leaf tissue where the mottling is heaviest.
- Tissue collapsing into brown dry spots on the mottled areas as the season goes on.
- Twisted, distorted new leaves in later years.
- A plant that steadily loses vigor over several seasons rather than dying outright.
Why it happens
A virus spread by sap. It has no insect vector at all: it moves on a knife used to divide two plants, on the sap left on a hand or a glove, on a broken leaf brushing a cut stalk, and above all through the nursery trade in divided plants. Some heavily mottled infected plants were sold as novel variegated cultivars in the 1990s and 2000s, which is part of how far it traveled.
Anywhere hostas are divided or handled. It does not spread on the wind or through the soil, so a garden that never divides its hostas and buys clean stock can keep it out entirely.
Treating it
- There is no cure. Dig the plant out, including as much root as you can, and bag it.
- Do not compost it and do not give divisions of a suspect plant away.
- Disinfect the spade, knife and gloves with a bleach or alcohol solution afterwards.
- Wait a season before replanting a hosta in the same spot, and remove any root fragments.
- Have a valued plant tested with a cheap commercial test strip before you dig it, since natural variegation and mottling do look similar.
Keeping it away
- Buy hostas from reputable growers and inspect the leaves for vein-following mottling before you plant.
- Divide with a clean tool and disinfect between plants — this is the whole route of infection.
- Avoid the deliberately mottled cultivars sold in the past on the strength of the symptom.
- Quarantine new plants in a pot for a season before adding them to the collection.
- Do not cut hosta leaves for the vase from one plant and then another with the same knife.
See also
The Cottage Garden Companion — the gardener's apothecary at cottagegardencompanion.com