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Killer virus ravages rose gardens in the USA

There is no cure, experts say, so the only way to stop the attack is to dig up all infected bushes and destroy them.

Marsha Ruse of Overland Park recently removed from her garden several rosebushes that were suffering from rose rosette virus,

Rose rosette

The symptoms include:

• Distortion and reddening of leaves.

• Uncontrolled growth of stems.

• Excessive thorn production.

Experts warn that some reddening from normal early-season growth, or herbicidal damage, could be mistaken for rose rosette.

Gardeners concerned about their rose plants can send samples to Kansas State’s plant pathology lab. To learn how to send a sample, go to www.plantpath.ksu.edu.

// Reports of a virus that attacks roses are proliferating around the Kansas City area, and experts say there is no cure.

The disease, called rose rosette, has been known throughout the Midwest for decades. But this spring, agriculture officials in Johnson and Jackson counties are hearing more reports from gardeners with sick roses.

In Overland Park, the disease has progressed enough this year that the city is planning to rip out several of its rose beds along traffic routes and at city buildings and replace them with other plants.

Sarah Patterson, the city forester, said officials didn’t know the cost yet but would tear out rose beds in at least four locations, including the intersection of Shawnee Mission Parkway and Metcalf Avenue, and at the Jack Sanders Justice Center.

“I think this is spreading more rapidly than most people realize,” she said.

Some home gardeners are being hit, too.

Marsha Ruse of Overland Park knew her roses were dying almost as soon as they bloomed this spring.

She has cared for the five rose plants for eight years, she said, and they have always been healthy. Ruse identified the reddened leaves, uncontrolled growth and excessive numbers of new thorns on her plants and knew she was going to have to destroy them.

“I’m very disappointed,” said Ruse, who volunteers with the Johnson County office of K-State Research and Extension. “The only way to do it is to dig them up and get rid of them.”

Ruse’s roses were of the Knock Out variety that has grown popular over the past decade with home gardeners, as well as commercial and municipal landscapers. Knock Outs are impervious to most diseases, but they are susceptible to rose rosette, which attacks all varieties of roses.

Experts recommend digging up and destroying infected plants. Microscopic mites, travelling on wind currents, spread the disease-causing virus as they feed on roses.

Commercial and retail landscapers said they have seen the rose disease throughout the area. Chad Gilliland, a plant care specialist with Arbor Masters, a landscaping firm in Shawnee, said he had seen more and more of the disease over the past five years.

“It seems like about every year it gets progressively worse,” he said.

Officials at the University of Missouri Extension in Jackson County have also heard more talk about rose rosette. Lala Kumar, a horticultural specialist, said he was hearing more reports of the disease this spring, and they were also coming earlier in the season. He said the disease tends to peak in June or July, but he has already taken four reports of it this year.

Laura Dickinson, master gardener coordinator at Johnson County Extension, said the county’s gardening help hotline averages two or three calls per month about rose rosette in most years. But this spring, Dickinson counts that many calls each week.

Not everyone has seen an increase in the disease, though.

Public works and parks officials in Roeland Park and Prairie Village said they had not had problems with rose rosette but were watching out for it. Kansas City’s parks department maintains 60 rose beds throughout the city that have shown no signs of the disease, said Forest Decker, superintendent of parks.

The virus occasionally appears in the municipal rose garden at Loose Park in Kansas City. Judy Penner, the director of the park, said she used a miticide — an insecticide for mites — to keep the disease in check.

Several experts warned that the disease can be spread by contaminated pruning shears and advised gardeners not to put uprooted plants in compost piles.

Raymond Cloyd, an entomologist at Kansas State University, said the disease-causing mites may have been introduced to North America before 1970 as a means of suppressing wild rose plants that were seen as a nuisance at the time.

Cloyd said using a miticide to stop the mites from spreading the disease would be only marginally effective because they burrow deep into the rose’s tissues. He recommended removing the plants and destroying them.

If the roots are completely removed, roses can grow safely in the same spot, but Johnson County Extension recommends waiting for a few weeks or until the next growing season.

THE UK IS NOT AFFECTED.

Details of all our roses are available on our web site. Over 1000 varieties to choose from.

www.countrygardenroses.co.uk



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