A new rose threat

Wed. Aug. 30, 2017

Click below to listen to my 2 min. Garden Bite radio show:  A new rose threat

Northern Gardener magazine is one of my all time favorites.  There’s a ton of great information, wonderful pictures and stories of what’s on the horizon.

This month I was reading about a new Rose threat.  Honestly, my roses did poorly this year until just about 3 weeks ago.  Odd, but they look beautiful right now.  I better enjoy them while I can.

Carpet roses 8-17

Gail Hudson writes about Rose Rosette Disease and folks, this one’s nasty.  RRD transforms your lovely roses into a deformed mess and then kills them in a couple of years!  Worse yet, the disease is pandemic.  Translation – it’s everywhere, it’s prevalent and it’s pervasive!

Rose rosette disease creates a ‘witches broom’

An international symposium was held in July wherein 20 countries were represented and the US team has discovered that more than 550 rose cultivars and species are susceptible!  Holy Roses!  To date, rose rosette disease has been either sighted or confirmed in 2 dozen states, mainly in the south and midwest but it’s also been confirmed at the Minnesota Landscape Arboretum.

Notice the discolored leaves and abnormal growth on the left? The right side is still normal

Several cases have been seen in Wisconsin, Iowa, Illinois and the Dakotas.  The cause of RRD is a virus that’s spread by a microscopic mite.   More information from the American Rose Society.

Phyllocoptes fructiphilus

I would also suggest reading this FAQ from Clemson University.  Another symptom is excessive thorns.

Rose breeder David Zlesak says “All you need is one mite to blow on your plant, it’s the sentence of death”.  The mites crawl inside the petals and scales of rose buds, hiding in leaf scars and young shoots.  Once infected, a rose shrub may contain hundreds to thousands of them per gram of tissue.  Yes, I said per GRAM of tissue.

In areas where temps get below minus 20 degrees, it’s believed the mites are significantly decreased.  The best solution for home gardeners is to be diligent, but keep in mind, there is NO CURE.  While researchers are working on various ways to breed resistant roses (there’s a wild rose they’re looking at) and some use of chemicals, it’s really not practical at this stage.

If you spot symptoms, remove the rose bush.  Cut it off at the base, dig it out and bag it in plastic.  Then toss it. Get it away from your other roses.