The Rosa genus, native exclusively to the Northern hemisphere, includes more than a hundred species from Asia, Europe and North America. Many years of selection and hybridization have produced over 20,000 cultivars in an amazing array of shapes and colours. Roses are available in every colour except blue, from scarlet red to bright yellow and every possible shade of pink.
At our latitude, hybrid teas, floribundas and grandifloras all require winter protection. Species roses and modern shrub roses, on the other hand, are very hardy – they are a good choice if you are looking for roses that require little maintenance.
Species roses, like Rosa gallica, for instance, have single blooms that appear only once a season. Modern cultivars of shrub roses are remontant, or repeat bloomers, with semi-double and double flowers. They include R. rugosa hybrids, the Explorer, Parkland and Meidiland series and English roses (Austin).
These roses are perfectly hardy to –35ºC (with good snow cover), resistant to common diseases and available in a wide range of colours. Their roots will send up suckers after a winter freeze. To keep them hardy, it is best to buy plants grown from root cuttings rather than grafted plants, or to plant the graft union well below the soil surface.
Rose bushes are sold in plastic bags or pots or with bare roots. You should look for healthy, vigorous plants with 4 or 5 sturdy canes and well-developed roots, and choose varieties known to be resistant to common fungal diseases.