Shrub roses are a mixed bag of plants. Shrub rose flowers range from singles to doubles to clusters. Hybrid rugosa are known for their winter hardiness, disease resistance and easy care. Rugosas survive well along road ways that receive salt spray during the winter. They also develop a formidable barrier with their spine-covered stems.
Hybrid musks have large clusters of flowers and are known for their heavy fragrance.
Most musks have single flowers and are generally winter hardy and disease-resistant. The catchall shrub subcategory includes a variety of plants, but most are large, disease-resistant and winter hardy. Generally the new hardy 'Canadian Explorer' and the 'Parkland' series of roses bred in Canada are considered shrub roses. The next main rose group are climbing roses. Climbing roses include all those cultivars that produce long canes and require tying to some sort of support.