Rosa Rugosa Genus & Species

Rosa --The Genus

• The genus rosa is a genus of the plant family Rosaceae and cousin to apples, cherries and raspberries. Ancient roses more closely resembled their brambling, fruiting relatives: small flowers with five-petals were numerous, and small edible fruits formed on shrubs covered with thorny prickles. Roses exist in such variety today in part because they have lived in gardens for nearly 5,000 years -- in China, on the island of Crete and in ancient Greece. In most temperate areas of the Northern Hemisphere, native species have been cross-bred for centuries. Roses grow as woody perennial vines or shrubs with compound leaves in groups of three, five or more. Flowers bloom above an ovary concealed in their bases and anthers rise above ovaries around the pistils in the center of blooms. The difference between species and cultivars -- cultivated varieties -- is often murky because roses have been selectively bred by humans for so long.

Rugosa --The Species

• Rosa rugosa, native to China, Japan and Korea, first caught the eye of western rose fanciers near the end of the 18th century. Harvard University listed more than a dozen rugosa hybrids in its 1932 arboretum bulletin, including F.J. Grootendorst, Blanc Double de Coubert and Max Graf that are still under cultivation. White, pink, red and purple flowers may be single, semi-double or double and re-bloom when deadheaded regularly. Rugosa's deep green leathery leaves resist disease but occasionally contract black spot. Rugosa stems bear hairy prickles that cover the stem rather than individual "thorns" typical of many hybrid garden roses.

Rugosa Pros

• Rugosas offer a variety of shrub roses, some growing up to 10 feet tall and some low-growing ground cover cultivars. Many rugosas are hardy to USDA zone 3 or 4 and are salt-tolerant, making them good seaside garden candidates. They grow on their own roots rather than grafted stock. Known for their disease resistance, they require little pruning. They re-bloom, providing a spicy fragrance in the garden during all but the hottest weeks of mid-summer. Plants produce impressive rose hips at the end of the season, providing food for wildlife.

Rugosa Drawbacks

• Plants tend to grow suckers -- non-productive shoots that draw energy away from flowering branches -- that you must remove for maximum flower production and to keep the plant from becoming weedy. Cold-weather hardy rugosas may require extra care in southern zones where summers are hot and dry. Because of their hardiness and suckering habit, they may escape the garden and become invasive: several states have listed them as invasive or nuisance plants.