Disease-Resistant Roses

Choosing the best variety of disease-resistant rose

By Graham Rice

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a variety of RosesRoses are notorious for disease. Mildew, blackspot, rust—what’s the point of growing roses if they look sickly and sad? But some roses have genetic resistance to disease, and while few are entirely free of problems, there are three healthy groups to consider.

Most wild species of roses are very healthy and resilient plants. Down the generations, natural selection has constantly worked in favor of disease-resistant genes as infected plants fail to reproduce well. I especially like Rosa glauca (hardy to USDA Plant Hardiness Zone 2), with grayish blue leaves, single pink flowers, and red hips. The pink-flowered swamp rose, R. palustris (Zone 4), is valuable not only for its healthy growth but for its unusual tolerance of damp soils. The Virginia rose, R. virginiana (Zone 3), also tends to stay quite healthy and is a good species for drier conditions. Its pink flowers are followed by bright red hips and fiery fall color.

There are also some lovely disease-resistant heirloom roses. The rugosas are among the healthiest—and toughest—of all roses, and their rough leaves are rarely infected. I especially like ‘Blanc Double de Coubert’ (Zone 3), with its super-scented, semidouble white flowers; and ‘Fru Dagmar Hastrup’ (Zone 2), with single pink flowers. Both have splendid orange-red hips.

Another group of disease-resistant roses are the hybrid musks. Their scent is superb and they have an unusually long flowering season. ‘Cornelia’ (Zone 6), in apricot fading to pink, and silvery pink ‘Felicia’ (Zone 6) are the ones to pick.

Then there are modern roses. Breeders once assumed their roses would be sprayed and never considered disease resistance. But top German breeder Kordes has not sprayed the seedlings from which it selects new varieties for more than 30 years. In Britain, Harkness Roses have been spray-free since 1998, and in Texas, The Antique Rose Emporium also refuses to spray. In the absence of fungicide sprays, seedlings with genetic resistance to diseases rise to the top of the trials.

Most of the recently introduced Kordes varieties are unusually healthy. I especially like ‘Kosmos’ (Zone 5), with peach-centered white flowers. From Harkness, the English Legend Series is worth looking at; again, focus on the more recent introductions. Among American varieties, take a look at the Pioneer Roses from Antique Rose Emporium and, of course, the Knock Out Series and the Oso Easy Series.

Photos: © Gardenphotos.com

Graham Rice @ Organic Gardening

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