Unlike some other rose varieties, they're heavy bloomers, easy to plant and maintain, and can be placed almost anywhere in the yard, even in partial shade.
They are not attractively shaped plants, not aromatic, nor equipped with large, single blooms on long stems that show well and last long in a vase.
"You have to choose what traits you're breeding for," said Steve Hutton, the president and chief executive officer of The Conard-Pyle Co., a nursery operation in Philadelphia specializing in woody ornamental and rose plants.
"You generally sacrifice some other traits," Mr. Hutton said. "Flower form is sacrificed in most modern shrub roses. Fragrance is almost nonexistent. ... Maybe when genetic engineering becomes really refined, we'll be able to take the Peace rose (hybrid tea) and take genes from the Knock Out (shrub) and transfer disease-resistance into hybrid tea roses."
If you want exhibition-style roses with the traditional look, then perhaps you should consider something from the hybrid tea and floribunda families, despite maintenance demands.
Here is a primer listing some of the major rose categories and their characteristics. Some can be grown in both the climbing or bush forms although bloom size, frequency and duration may vary:
HYBRID TEAS: These are the most admired of the modern garden roses, with more purchased than any other. They can be recognized by their large, double flower blooms that spiral toward elongated centers, their brilliant and varied colors and generally long, single-blossom stems.
They need protection, however, from extreme cold and a variety of diseases. Some glorious examples: Sheer Magic, Double Delight, Memorial Day, Mr. Lincoln, Peace, April in Paris.
FLORIBUNDAS: Hardy and long-blooming flowers on small, compact bushes. The blossoms are produced in clusters. They also need cover in winter. Some noteworthy choices: Honey Perfume, Tuscan Sun, Dainty Maid, Iceberg, Lovestruck, Mardi Gras.
GRANDIFLORA: Similar in size and beauty to the hybrid teas but with large flowers in large clusters on large bushes. Some fashionable choices: Arizona, Honey Dijon, Montezuma, Comanche, Queen Elizabeth.
POLYANTHAS: Small bushes with rich, re-blooming clusters of smallish blossoms. Great for tight spaces. Among the choice varieties: Cecile Brunner (Sweetheart rose), The Fairy, Gentle Maid, Candy Cane.
OLD ROSES: All pre-1867 or before the first hybrid tea varieties. Cherished for their histories, aromas and colors. Some of the classics: Charles de Mills, Rosa Mundi, Leda, Marie Louise.
MINIATURES: Small in plant size, stem length, foliage and flowers. Several standouts to look for: Sun Sprinkles, Cupcake, Petite de Hollande.
CLIMBERS: Ramblers or large-flowered. Ramblers tend to bloom only once with large clusters of small flowers. Fast growing and hardy. Large-flowered climbers are the aptly-named varieties often seen wrapped around arbors and trellises. They have fewer but larger blooms. Some of the notables: Fourth of July, Golden Showers, Improved Blaze, American Pillar.
NEW SHRUBS: Trouble-free, disease-resistant and easy to grow. Make great borders planted en masse. Collectibles: Knock Out series (Conard-Pyle), Flower Carpet series (Tesselaar), Good 'n Plenty (Jackson & Perkins).
Despite low maintenance requirements of the new shrub roses, traditional rose sales won't be disappearing soon, Conard-Pyle's Hutton said.
"There's still a large market for the exhibition style roses - primarily from rose enthusiasts. ... Novices, though, would do well to look for the best and most disease-resistant roses they can find."