A friend at the U of Minnesota is a biochemist and they are looking at biochemical components between genotypes of a specieis that differ for tolerance with the goal to understand that source of better tolerance/resistance for future deterrent sprays, etc. They are looking at grapes, birch, and I think some other groups of plants and would love to work with roses. There isn’t too much out there about different levels of tolerance between roses. Some sources say darker colored roses are more tolerant, but then when I look at ‘Hope for Humanity’ blooms year by year covered with beetles, it doesn’t seem to fit.
It seems like polyanthas and minis may be bothered less and maybe taller, larger roses are bothered more. Wonderfully fragrant roses like Dee-LishTM seem to draw lots of beetles to the flowers. I remember years ago when Francis Meilland was an AARS test rose noticing it wasn’t bothered as much as the neighbors, so that one may be promising for the study.
Any insights for which roses (especially if they are commonly available) seem to be better than others that she could try would be greatly appreciated.
I’m so glad I don’t have those little buggers yet.
My observations for the past few years have been that my pink roses are devoured by beetles far more frequently than my yellow roses. In particular, they are very fond of Rosa palustris. So much so that at the height of the beetle season, I use a wide, shallow container of soapy water to knock them into because it’s able to catch more of them as they fall.
-Jonathan
My roses are surrounded by 12 acres of concord grapes, so there are a ton of Japanese Beetles. If anyone comes up with some info, I’d love to see it.
Henry- Thanks for the link to the old posts. Quite a bit of useful information in there. I planted some garlic around some roses this year to see if that might keep them away.
I don’t know any that are resistant. I learned to buy varieties that open inside after being cut in a tight bud. I remember Mr Lincoln being a good one.
I have never seen such a Japanese beetle overhere but… I would think… if the beetles come from Japan, then there is a bigger chance that Japanese species roses are less susceptible to this insect. So I would look into rosa rugosa (hybrids) but maybe also into rosa multiflora hybrids?
It’s peak Japanese beetle season in my part of Georgia right now. Twice a day, I make the rounds of the garden with my “poisoned chalice”–a Solo cup full of soapy water. When the air is warmer, the beetles seem to be more on the alert and it’s harder to knock them into the cup for their last bubble bath. Morning and evening are better.
Most large-flowered roses (shrub, HT, Floribunda, climber) that are in bloom are targets, regardless of color. The beetles seem to go for flowers when they are available. Favorite beetle fodder: About Face, McFarland Rose, Carefree Celebration, Carefree Sunshine, White Drift. But they also love rose leaves–The Gift, Henri Martin, and all Rugosas (these are not currently in bloom) seem to have tasty leaves.
Spinossissimas are long past their spring flush, but their leaves don’t seem to be palatable. Minis also seem less popular. I have two young Teas, both recently planted and not in bloom; no beetle visits on these so far.
I have a potted hibiscus on the patio and often find a solitary beetle chewing away at its leaves as well. No accounting for tastes!
Come to think of it, the reason the beetles don’t like minis can’t have anything to do with height. I have Carefree Celebration/Coral Knock Out planted right next to some minis and minifloras. It’s the same height and even flops over on one of them, but the beetles congregate on Carefree Celebration and eat it to rags, and ignore the minis.
I forgot to mention the other species. Rosa carolina, Rosa multiflora, and Rosa setigera seem to have tasty leaves. Leaves of Rosa arkansana, Rosa glauca, and Rosa xanthina are not on the beetle menu. I have seen beetles make a halfhearted attempt at Basye’s Blueberry, but why bother when they have McFarland Rose and Frau Karl Druschki so close at hand?