Budding and full-bloomed UK roses. A rose is a woody perennial of the genus Rosa, within the family Rosaceae. There are over 100 species. They form a group of plants that can be erect shrubs, climbing or trailing with stems that are often armed with sharp prickles. Flowers vary in size and shape and are usually large and showy, in colours ranging from white through yellows and reds. Species, cultivars and hybrids are all widely grown for their beauty and often are fragrant. Rose plants range in size from compact. The sharp objects along a rose stem are commonly called thorns, they are technically prickles. Rose prickles are typically sickle-shaped hooks, which aid the rose in hanging onto other vegetation when growing over it. Roses are a popular crop for both domestic and commercial cut flowers.