Hosta Virus X (#30-09)

	By Sara Williams


	It never ceases to amaze me as to how unobservant one can be in one’s own garden. It 

	took a friend to point out that my ‘Sum & Substance’ hosta was showing obvious signs of

	infection from a virulent disease known as Hosta virus X. If your hosta looks like mine,

	you may also have infected plants.

	
	In the 1600s, at the height of “Tulipmania” in Holland, fortunes were lost and won in the

	trade of tulip bulbs with flowers of unusual stripping and stippling. Although highly 

	prized, these tulips were seldom long lived. With the hindsight of four centuries and a 

	liberal dose of modern plant physiology, we now recognize that the stripping was due to a

	virus that was also the cause of their untimely death.


	Botanical history is now repeating itself, this time with Hosta. A popular shade plant

	easily propagated by division, except for slugs, Hosta have long been regarded as pest-

	free and virtually undestructable. Weird mottling is not unusual in hostas and is generally

	due to simple colour mutation. Some plants, with characteristics now known to be caused 

	by Hosta virus X, were actually introduced and sold, thus rapidly spreading the virus far

	and wide. Among these were ‘Blue Freckles’, ‘Breakdance’, ‘Eternal Father’, ‘Kiwi

	Watercolours’, Leopard Frog’ and ‘Lunacy’. Lunacy, indeed!


	First described in 1996, gold leafed cultivars seem particularly susceptible to Hosta virus

	X. Among the varieties that are highly susceptible are some of our favourites: ‘Birchwood

	Parky’s Gold’, ‘Blue Cadet’, ‘Gold Edger’, ‘Gold Standard’, ‘Goldrush’, ‘Honeybells’,

	Royal Standard’, ‘So Sweet’, ‘Stiletto’, ‘Striptease’, ‘Sweet Susan’. ‘Sum & Substance’,

	and the species Hosta undulato ‘Albomarginata’ , H. ventricosa, and H. venucosa. This

	list is not complete but serves as an indication of plants to be aware of.


	What are the symptoms that gardeners should be on the lookout for?  According to the

	University of Arkansas Cooperative Extension, “The most common symptom is bleeding 

	of color along veins with blue or green mottling on the leaf surface…The virus may also

	cause the leaves to pucker, twist or develop mosaic ring spots.” Dead spots may occur

	within a leaf or entire leaves may die. The virus itself may be present for years without

	the plant dying, but may be spread to other hostas during this period.


	Although many virus are either soil borne or spread by insects, Hosta virus X is believed 

	to be spread by the movement of sap from an infected plant to one that is not infected –

	generally through division or by brushing or breaking a leaf or other plant part. Be very 

	careful to clean your tools with a 10% bleach solution when “cleaning up” or

	deadheading plants. If you suspect a plant is infected, remove all of it (including root

	pieces), and place it in a plastic bag in your garbage. Do not compost it. Disinfect the tool

	that you used to dig it up. Be discerning as to where you purchase hostas.


	Here are some guidelines for protecting your hostas: Clean tools and hands between each 

	plant. Leave dead leaves and spent flowers on your hostas. Be observant. Look for the

	symptoms. Buy from reputable nurseries, avoiding cheaper “box store” hostas. 


	Spread the word about Hosta virus X among your gardening friends. Be observant in their

	gardens, as my friend was in mine! 


	Sara Williams is the co-author (with Hugh Skinner) of Best Trees and Shrubs for the

	Prairies as well as the newly released Best Groundcovers and Vines for the Prairies. She 

	gardens on 5 acres near Saskatoon.>BR>


	This column is provided by the Saskatchewan Perennial Society. Coming events include:


	July 26 -  Friends of the Forestry Farm House, open house of the Superintendant’s House,

	1:30-3:30 with walking tour at 2 pm; refreshments available; call 652-9801.


	Aug. 8 – Saskatchewan Perennial Society, Labour & Learn work bee, Robin Smith

	Meditation Garden & Heritage Rose Garden, Forestry Farm Park, 9 am, bring your own 

	tools. Call 343-7707


	Aug. 11 Saskatchewan Perennial Society, Labour & Learn work bee, Robin Smith

	Meditation Garden & Heritage Rose Garden, Forestry Farm Park, 6 pm, bring your own>BR>
	tools. Call 343-7707>BR>


	Aug. 16 – Saskatchewan Perennial Society, Fruit Tree Tour, meet at the Little Tree

	Nursery, 321 Centennial Drive, North, Martinsville, 2 pm.