Growing Roses In Cold Climates

Different types of roses have different tolerances to cold winter temperatures. The lowest temperature a rose can withstand without injury is called its winter hardiness. Several factors influence whether a plant reaches its full hardiness, and consequently, a plant's hardiness is generally given in a range. For example: Most popular hybrid teas, floribundas, climbers, and grandifloras can survive 10° to 20°F (-12° to -6°C) temperatures without any winter protection.

Miniatures, because they grow on their own roots and do not have that vulnerable bud union, are hardier.

Many species and shrub roses are hardier still. For example, rugosa roses are said to be hardy to about -35°F (-37°C). But, even within groups of roses, different varieties can be hardier than others. For example, the lovely white hybrid tea 'Pristine' does not seem to like temperatures much below 30°F (-1°C). Rosarians in cold-winter climates who cannot live without 'Pristine' treat it like an annual and replant it each year.

Most rose books and some catalogs list hybrid tea roses as being hardy to between -10° to -20F (-23° to -29°C), but that is with some type of winter protection such as mounding soil over the base of the plant. Without any kind of protection, modern roses, like hybrid teas, floribundas, and most climbers, are often damaged by temperatures of 10°F (-12°C) and colder.

Rose hardiness is not at all precise. In fact, sometimes it is downright confounding. Early cold snaps in fall, or late ones in spring, can damage plants that you normally think of as being hardy. And different types of cold damage exist. Sometimes, just the tips of the canes die; other times everything above the ground dies; and occasionally, the whole plant ends up deader than a doornail. To further complicate things, dry winter winds, bright sunshine, and even how you care for a rose prior to cold weather affect its capability to withstand winter weather. Luckily, most roses are relatively easy to protect from the ravages of winter.

If you live where temperatures regularly drop below 10°F (-12°C), use these strategies to give your roses a fighting chance:

Plant hardy roses. Many roses have good cold hardiness. Many single out the hardy varieties that they sell. Grow own-root roses. They are hardier than budded roses because they grow on their own roots (like most miniatures and many old garden roses and shrubs) and do not have that vulnerable bud union that most modern roses have. If winter kills your own-root rose to the ground (but not below the ground), it is more likely than a budded plant to re sprout true- to-type in the spring.

Plant deep. If you do not buy own-root roses, plant deeper than normal so that the bud union is well below the soil surface and protected by the layer of soil above it.

Use winter protection. Where winters are really brutal (-30°F or -34°C and colder in U.S. Zones 1 through 4), you are best off with the hardiest shrub roses, particularly any of the Morden and Explorer series from Canada and any of the rugosas.

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