Although most roses will grow in a range of climates, many are susceptible to drought, dampness, heat, cold, and other extremes. If your climate is less than ideal, you can guard many sensitive roses by planting them in protected spots or by giving them extra care. But it is far better to choose varieties that can stand up to the worst your climate can inflict. Here are some guidelines for selecting the right ones.
Drought and Dampness
Although no rose will thrive under drought conditions, R. rugosa and its hybrids do better than most, surviving without water for several weeks at a time once the plants are established. They will also tolerate the salt air and sandy soil that are found in beach zones.
At the other extreme, many roses are susceptible to the fungal diseases that prevail in damp climates. Yellow roses in particular are susceptible to black spot. If you live in a humid or rainy area, you need to pay strict attention to a program of preventive spraying. In these circumstances, choose a disease-resistant variety. In damp, cloudy regions you may wish to avoid roses with very double flowers, which may not open properly if they are constantly moist or if they lack the heat of sunshine to open them before they start to fade.
Rose gardens in warmer climates, be they in subtropical, tropical, or desert areas, can be very successful if you select the right roses. Most modern roses will not live long in these climates, since they quickly exhaust themselves when denied winter dormancy Two notable exceptions are the floribunda ‘Iceberg’ and the grandiflora ‘Queen Elizabeth’, which rose growers in subtropical Bermuda have found to be quite long-lived. In general, however, the best choices for hot climates are the old garden roses, especially Chinas, teas, hybrid perpetuals, and shrub roses. Yellow roses tend to fade in the heat, so this is a color you may want to avoid in such climates.
You may be able to coax a wider range of roses to grow in hot climates by taking some extra precautions. Keep the soil from drying out too quickly by working in extra organic matter and covering the surface with a mulch. Keep the plants from drying out by sheltering them from the wind. Protect your roses against burning by placing them where they will be shielded from the glare of the afternoon sun.
Gardeners who live in cold northern regions must face the fact that their climate is less than hospitable to some types of roses, which cannot adapt to cold weather. Although burying or covering these varieties will help many of them to survive the rigors of winter, choosing roses with built-in hardiness can enable you to avoid this drudgery. This is a special boon to people whose time for gardening is limited.
Unfortunately, no one has ever tested each rose variety for winter hardiness in all of the 11 climate zones designated by the U.S. Department of Agriculture. This is despite the fact that nearly every other garden plant has been assigned a hardiness rating. However, the roses in Roses That Tolerate Cold can be expected to be hardy to Zone 6 (where average minimum temperatures range between -10 degrees and 0 degrees) without winter protection.
Some can withstand the colder winters of Zone 5 (between -20 degrees and -10 degrees) and Zone 4 (between – 30 degrees and -20 degrees).
In addition to the plants listed, most ramblers are hardy to at least Zone 6, and many are hardy to Zone 5. Shrub roses other than those listed are hardy to at least Zone 6. Old garden roses, except for tender China, noisette, and tea roses, are hardy to Zone 6, and centifolias and damasks are hardy to Zone 5.
Most roses need full sun in order to grow and bloom successfully. However, a few can do with less sunlight than others. The roses that are most tolerant of shade are the hybrid teas ‘Blue Moon’, ‘Christian Dior’, ‘Fred Edmunds’, ‘Garden Party’, and ‘Swarthmore’; the shrub rose ‘Alchymist’; the rambler ‘Etain’; and all of the hybrid musks. In addition, many climbers and miniatures can grow in less sun than other roses. However, no rose will thrive with fewer than four hours of bright sunshine per day.