These deciduous shrubs needs lots of sun, good air circulation, regular water and lots of fertilizer (Maxsea, EB Stone Rose and Flower Food). Only the climbers should need staking (plant ties).
Roses are prone to fungal diseases like rust, powdery mildew and black spot. You can use either the Citrus/Fruit/Nut Orchard Spray or Rose Defense. Both should be applied late in the day to avoid killing any beneficial insects and burning the leaves from the hot sun overhead. Water before noon to help control fungus.
Right now roses are being attacked by the Rose Curculio/Rose Weevil. This critter is roughly ¼ inch long, bright- red to dull black with a pronounced narrow, black curving snout.
Curculio damage will leave small holes in petals, stems broken just below the buds and buds with holes punched in them.
The larvae will drop to the ground to pupate in the soil over the winter. Apply Beneficial Nematodes under roses when the fall rains begin to control the single annual generation of adults that emerge in late spring.
To control the adults now you can apply Rose Defense or Greenlight Spinosad, applied late in the day.
You can also gently shake the canes/flowers over a bucket of soapy water to collect the adults. They may drop to the ground where they will ‘play dead’…don’t let them fool you. They will flip over when you turn and scurry away.
Remove spent blooms and hips and any damaged blooms to reduce the population. Rose curculios are most active in the late afternoon (4ish) and seem to prefer white, yellow or peachy blossoms.
Bristly Roseslugs appear when the weather gets warm and damage the rose leaves by chewing many holes, leaving behind a lacy remnant of a leaf. These little green critters stay under the leaves and resemble caterpillars…but they are actually a Sawfly larvae. They will not be killed by Bt (Caterpillar Killer) but can be controlled by any of the insecticidal soap sprays we carry. The spray must be applied directly on the critter.
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