CORVALLIS, Ore. – Struggling with rose diseases often converts affection to frustration for the millions of gardeners who grow the beloved shrubs.
Instead of cursing the big three – black spot, powdery mildew and rust – take the advice of Jay Pscheidt, a plant pathologist with Oregon State University Extension Service, who steers people to roses that enjoy immunity to the threats of these diseases.
“Save yourself a lot of hassle and plant disease-resistant roses this spring for trouble-free bouquets in the summer,” he said. The Pacific Northwest Plant Disease Handbook, which Pscheidt co-authored, offers a list of varieties.
Hybrid teas that smell sweet and are moderately resistant to all three diseases include dark-red Mr. Lincoln; Double Delight with its shades of reds, pinks and whites; pastel pink Tiffany; and sunset-orange Voodoo. Dark-salmon Fragrant Cloud is highly resistant to rust and moderately resistant to powdery mildew and black spot.
Tournament of Roses, a coral-colored grandiflora, and the heavy-blooming, pink-flowered floribunda Sexy Rexy very successful at fighting off the trio of diseases. Sunshine-yellow floribunda Sunsprite and Queen Elizabeth, a classic pink grandiflora, are moderately resistant to all three.
If you want a climbing rose, keep in mind that they require more pruning than shrub roses. Install a trellis or use an archway for a climbing rose, which needs space to grow vertically as well as horizontally.
Disease-resistant climbing roses include the fire engine-red Altissimo, which is resistant to rust and has medium resistance to black spot and powdery mildew. Lemon-yellow Golden Showers and Joseph's Coat in rouge and peach hues possess moderate resistance to all three.
You may not find all of these roses at garden centers and other retail outlets. If you’ve got your heart set on one, call first to see if it’s in stock. If you choose to shop online, check out Heirloom Roses, Jackson & Perkins and Edmunds Roses.
At the nursery, roses come with bare roots or in a plastic container. For container plants, dig the planting hole twice as wide as the container. For bare-root roses, dig the hole wide enough so you can spread the roots horizontally. Spring, after the last frost date (late March/mid-April), is a great time to plant roses. Put them in a spot with well-drained soil that will receive six to eight hours of full sun. Water your newly planted roses deeply.
For more information about roses, refer to Controlling Diseases and Aphids on Your Roses. Also available is Roses: Planting and Care in Central Oregon. Although it’s geared for high-desert gardeners, the advice also applies to western Oregon.