Polyantha roses are low, very hardy plants that continuously produce large clusters of small blooms and survive winters unprotected as far north as Zone 5. Indeed, "many blooms" is what the Greek word polyantha means. The blossoms are small, rarely exceeding 2 inches in diameter, and the plants are generally 2 feet or less in height, which makes them ideal for massing in beds and for use as low hedges. They are also widely grown by florists as house plants for Easter and Mother's Day, after which they may be set out in the garden. More than most roses, polyanthas bloom profusely not only on old canes but also on new canes that spring from or close to the ground. This tendency of polyanthas to have a number of canes and stems at different stages of maturity at the same time ensures a steady supply of flowers week after week.
Polyantha roses range in color from deep red all the way to white, with many lovely shades of pink; there are also some yellow, salmon and orange varieties. The blossoms are either doubles, with as many as 45 petals; semidoubles, with less than 20 petals; or singles, with five to seven petals. Only a very few varieties have much fragrance. But it is scent, as well as form and color, that helps account for the continued popularity, after almost a century, of the best known of the polyanthas, the bright pink-on-yellow, delicately fragrant CÚcile Brunner, the original Sweetheart Rose. Other varieties have become less popular as polyanthas have to a great extent been replaced by their larger and more spectacular offspring, the floribundas, which were bred from polyanthas and hybrid teas.
Courtesy of Time Life Plant Encyclopeadia