Hello fellow readers, Two unsightly rose dilemmas came to my attention, requiring a revisit of suggested rose remedies. We’ve chatted before about the plethora of rose challenges such as spider mites and aphids that often run amok. Never mind the fungus amongst them like black spot and powdery mildew they are famous for. Then there’s deer who enjoy nibbling, which is odd given their prickly nature.
Holy rose remedies are often manageable.
Carolyn’s holy roses are far more manageable than fungus. I suggest Bonide’s Pyrethrin Garden Insect Spray (link below). You can use Pyrethrin, derived from chrysanthemum flowers, even on edible plants. Yet, it immediately impacts an insects’ nervous system killing them. Be sure not to spray when beneficial pollinators such as bees and butterflies are present.
Pat’s dilemma is more complicated. She sent photos of her climbing roses in distress, about five weeks after we tended to fertilizing and pruning them. After which, her knockout roses were doing beautifully and still are. And, the climbing roses, previously shy on blooms, filled with buds.
Fungus is more challenging.
“Only a few buds bloomed,” Pat said, “The others get bigger but don’t open and turn brown on the canes.”
Rachel and Andrew, associate gardening gurus, thought perhaps the recent heatwave and dry spell might have invited fungus. Be sure the plants are adequately moist using a handy-dandy soil moisture meter costing less than 15 bucks. Of course, remove diseased buds and foliage as best you can.
They, like I, primarily rely on organic practices and “while, not our favorite, but sometimes its necessary to treat with a rose systemic,” writes Rachel. She didn’t have one to suggest as she rarely uses it. So on with the research cap.
Rose remedy tips for fungus
There’s an informative article by the American Rose Society, but despite the title, Fungicides Made Simple, culling through the information is a tad complicated.
There are contact fungicides to spray on the leaves and others you apply with water to the roots — the latter is less risky to use. And contact fungicides aren’t as effective as systemic ones, which makes sense. Systemic means it absorbs into the plant and won’t wash off in the rain.
A popular systemic drench is Bonide’s Rose RX System Drench which you apply to the soil. They say it controls insect and fungal disease for up to six weeks. But the product label and safety data sheets, plus a list of restricted states, raises a red flag.
Prevention is the best rose remedy of all.
Like all diseases, prevention is vital. Be sure roses receive six to eight hours of full direct sunlight and are spaced at least two feet apart from other mature plants. And when irrigation is needed, only water the roots to prevent wetting the leaves.
The American Rose Society suggests not to over-fertilize, adding further stress to plants. And rotate fungicides to prevent the plant from becoming “resistant to chemical treatments.” Oh my, see what I mean about roses being fussy?
Most fungicides only protect uninfected growth from becoming diseased. So it’s best to apply them when conditions are ripe for fungus. Blackspot spores tend to germinate between 65-85 degrees on foliage that is moist for seven hours or more. And powdery mildew when it’s dry with high humidity and warm days with cool nights.
A few suggested preventative fungicides include Rose Pride, Rose Defense, and products containing Neem oil. Neem oil is my go-to natural alternative that discourages both fungi and parasites.
So if Pat can manage, I suggest she grab a ladder and spray her climbing roses weekly, along with removing diseased buds and foliage, until healthy new growth emerges. Easy for me to say rather than do, as I’m a tad nervous climbing ladders.
Yes, roses can be fussy. But when roses are in their glory, they indeed are glorious.
We suggest Stress-X, our go-to remedy for stressed plants by North Country Organics, to help plants recover. I’ve used Stress-X on transplants even during the heat of the summer when plants are in bloom with great success. You can search online for other brands of soluble seaweed and kelp extracts should Stress-X not be available nearby.
You’ll enjoy previous columns featuring roses:
and Foxes in the Garden also featured in Episode 24 of the Garden Dilemmas Podcast