By Glenn DiNella
While I was in graduate school at North Carolina State, I had a great job working at the Raleigh Rose Garden, caring for the 1,200+ rosebushes at this well-loved city park. If I learned one thing from my experience, it was this: Roses are starved for attention. I don’t care what kind you have—hybrid tea roses, shrub roses, climbing roses, old roses—they all require some maintenance. I’ll take you through my year of basic training, season by season.
Depending on how harsh the winter was and which USDA zone you live in, it’s time for Southeast gardeners to wake up roses from mid-February to mid-March. Every plant is unique, but start by pulling back leaves and mulch gathered around the base, and prune out dead or broken canes.
Next remove canes that appear weak, small, diseased, or old and unproductive. Try to create an eye-pleasing candelabra shape, with the canes growing outward. This also opens up the center to improve air circulation and cut down on fungal diseases.
Add a slow-release rose fertilizer around the drip zone of your roses.
Late-spring rains and summer humidity bring fungal problems, such as black spot, to roses. The lower leaves turn yellow and then fade to spotty brown and black as they fall off. Gather the leaves and dispose of them (don’t compost) to prevent spreading this soil-borne disease. Spray the infected plants with a fungicide labeled for roses.
To prevent spreading black spot, if rains are scarce, set up drip irrigation or soaker hoses to water the soil around the base of roses (not the foliage).
Another dose of slow-release fertilizer keeps your roses healthy and blooming into fall. Deadheading (cutting off spent blooms) also encourages flower production.
This is the time to cut back long canes that might whip around in winter and break at the base. You can cut them back to a couple of feet so they can withstand winter gusts.
Spray dormant oil on your rose canes to smother pests trying to use your roses like a winter home in Boca Vista. Pick a time before bud break, when the forecast calls for no precipitation and no freezing temperatures for several days. Now you and your roses can rest for a month or two until it’s time for spring chores again. Whew!
Pests and Diseases
- Rose cane borer — A small hole in the center of a cane is evidence a cane borer has entered. Cut the cane back, until you no longer see a hole in the center, and dispose of it.
Some rose growers swear dabbing on a drop of paper glue (such as Elmer’s) immediately after pruning helps prevent cane borers from tunneling into the cane through the cut you just made. The scientific jury is still out on this one, but I figure it can’t hurt.
- Rose rosette disease — actually a virus spread by a type of mite—is a frightening malady that began showing up in the Southeast a few years ago and has made it as far south as Birmingham, Alabama. The plant might appear as if it’s been sprayed with glyphosate (Round-Up): Leaves dry out, curl up, and turn brown. The canes develop witch’s broom clusters and lots of fleshy thorns. Plants die within two years. There is no cure, so all you can do is dig up the shrub, bag it in plastic, and dispose of it.
- Aphids appear in early spring and love to suck the juices from tender rose foliage and blooms. Try using a light horticultural oil to smother aphids without burning tender rose foliage. Serious organic gardeners purchase ladybugs and release them near their roses. During its lifetime one ladybug can eat approximately 5,000 aphids.
Dealing with Japanese Beetles
Japanese beetles usually appear in early May in my Zone 8 garden in Alabama, chewing on foliage and flowers. You can use numerous remedies on these voracious bugs, which possess an unquenchable thirst for rose petals and leaves.
Pheromone traps can bag hundreds of Japanese beetles, but some gardeners swear they just attract more. If you use a pheromone trap, place it in the corner of your yard, far away from your most prized plants.
Sevin dust is one of the more mild insecticides—it’s even approved for use on vegetables. It’s easy to use and effective immediately.
Milky spore powder is a slow organic method that uses bacteria to target beetle grubs in the ground before they hatch.
A combination fertilizer/systemic insecticide applied in early spring beats spraying the plants with a broad-spectrum insecticide and killing off bad and good insects. Systemic insecticides get into the sap of the plants, targeting chewing pests. If you haven’t had a bug problem in the past, forgo the insecticide, but fertilize your roses in spring with a formula designated for roses.