A Rose Primer
Hybrid Tea roses are what most people think of when they envision a rose. Buds are usually pointed, developing into double, often fragrant flowers. Flowers are usually borne singly on long, straight stems, making them good for cut flowers. Foliage can range from mid green to dark green to deep red. The plants will flower spring through autumn, but flowering tends to occur in flushes with some cultivars. Grandiflora roses are similar in size and shape to hybrid teas, but usually flower in clusters of 3-6.
Floribunda roses are free branching, multi flowering roses. They are usually smaller than the hybrid teas, typically growing 2-3 feet tall. Flowers are single or double, depending on the cultivar. Flowers occur in clusters of 3-25 individual flowers. Compared to hybrid teas, floribunda roses require less pruning, and water and fertilizer. Polyantha roses are similar to floribundas, except they bear smaller flowers that are rarely scented. However, polyantha roses perform well in pots and other containers.
Climbing roses do not actually climb. Vines climb by twisting around a support, or attaching to it through tendrils or aerial rootlets. Climbing roses have none of these, but produce very long canes that can be attached to a support. Some cultivars reach heights in excess of 30 feet. Foliage is mid to dark green, and the canes have an abundance of thorns. Depending on the cultivar, flowers can be single or double, fragrant or not, occur singly or groups of 3-7+ flowers. Some cultivars are spring bloomers, putting on a single great show while others bloom continuously.
Shrub roses is a term applied to a diverse collection of garden roses. These plants are adaptable to many landscape situations, are often disease resistant, and some do not require dead-heading for continuous blooming. Flowers are smaller than the hybrid teas, and often assume shapes other than the classic rose shape. But what these blooms lack in size, they usually make up for in numbers, and continue through the growing season. Many also have fragrant flowers.
A sub-class of shrub roses are David Austins English Roses. These roses have undergone extensive breeding and combine the benefits modern roses with characteristics found in antique roses. The result are roses that bloom prolifically, display vigorous growth, have a pleasing fragrance and a wide range of colors.
Rugosa roses are a vigorous class of roses with deep green crinkled foliage. They can quickly overwhelm a small space as they send up suckers. The plants are very disease resistant but are very thorny. They bloom in spring, and many will re-bloom in the fall if dead-headed. If the bright-orange hips are allowed to form, birds will use them as a welcome food source.
Bare root roses usually show up in nurseries in early spring. They are packaged in plastic bags or tubes of a moisture retentive material around the roots. This material is often composed of wood chips, saw dust, peat moss, or a combination of materials. These roses should be purchased and planted before the top growth begins. Bare root roses with active top growth should be avoided because they lack an adequate root system to support the top growth. Many times bare root roses are dipped in wax to help preserve moisture. This does not affect plant growth and does not need to be removed.
Potted roses are arrive in nurseries after dormant, bare-root plants. They are usually grown in 1, 2 or 3 gallon pots. Top growth may or may not have begun. The advantage they have over bare root roses is they have an adequate root system to support any top-growth that occurs.
Bud and bloom roses are similar to potted roses, except they are taken one step further. These plants are held in the greenhouse grown on after dormancy has broken. When they arrive in the nursery, they already have several buds and maybe even some open flowers.
Several specialty potted roses can be found in area nurseries. Among these are roses that are potted in a box. The box is planted with the rose so the soil ball is not disturbed. The sides of the box should be scored to ensure rapid decomposition. Pots may be made of other biodegradable materials such as paper-mache. These should also be scored at planting time to ensure rapid decomposition.
Many varieties or cultivars are available. A color, size, or flower habit can be found for any landscape situation. When considering cultivars, choices exist in both patented and non-patented forms. Patented roses are newer cultivars. Breeders can receive a patent for cultivars they develop. They receive royalties from the sale of their cultivars to cover their expenses and fund future work. Patents currently last 20 years and are non-renewable. Non-patented roses are older cultivars whose patent has expired. These are the tried and tested cultivars, and have been grown in the garden for many years. They can also be as low as 1/3 the cost of a patented rose.
Roses are graded according to a set of standards approved by the American National Standard Institute (ANSI). Roses are graded as #1, #1½ , and #2. Grades are based on length, number and thickness of the individual canes. Number 1 is the highest grade, and #2 usually the lowest sold. Gardeners should only use #1 or #1½ roses.
As with any garden plant, soil preparation is critical to successfully growing roses. They thrive in moist but well-drained soil amended with plenty of compost. Compost or other organic matter is preferred for amending clay soil over sand. Dig the hole twice the size of the container, and work in plenty of organic matter in the bottom of the hole as well.
Bare root roses should be placed in a hole at least 2' in diameter. The roots should be soaked in a bucket of water a couple hours before planting. Rose roots must be in contact with the soil for best results. To best achieve this, a cone of soil is placed in the center of the hole and the roots fanned out over this cone. Soil is then added to fill the hole. Do not pack the soil with the shovel or other tool. This drives out the desired air space as well as the unwanted air pockets. Instead, fill the hole half-way with soil. Water well to settle the soil, then add the rest of the soil. Water again to complete planting.
For the greatest number of blooms, the plants should receive as much sun as possible. Although the plants will tolerate light shade, blooms will be fewer in number and the plants will be poorer in quality.
Roses are heavy feeders. A balanced fertilizer should be applied in the spring and again during the growing season. Liquid fertilizers are also effective because the fertilizer is immediately available to the plant. However, these types leach out of the soil quicker. All fertilizing should stop around Labor Day. This will give the plant a chance to harden the current seasons growth before winter.
One cultural aspect perhaps most important to growing good roses is to keep the plants well-watered. Roses use a tremendous amount of water and should not be allowed to dry out. When watering, better results are obtained by deep, thorough waterings instead of light, daily waterings. A layer of mulch will help reserve soil moisture, keep roots cool, and reduce weeds.
Pruning helps maintain form and health of the plant. Major pruning should be reserved for the plants dormant period, during late winter to early spring. For best results use sharp, by-pass type pruners. Added protection can be obtained by sterilizing the pruners with bleach or alcohol.
Pruning begins with the removal of weak, damaged, or diseased canes. Suckers which originate below the graft should also be removed. Cut back hybrid teas to about 18" to 24". This will promote vigorous new growth and improve flowering. Floribundas and polyanthas require less pruning, but can be cut back to about 18". Always cut to an outward facing bud. This encourages a V-shaped growth habit, letting light and air reach the interior of the plant.
Climbers should not be pruned the first two years after planting, except to remove damaged or diseased wood. Beginning with the third year, climbers can be pruned to fit their support.
Shrub and rugosa roses that bloom once a year should be pruned after flowering. Remove up to 1/3 of the stem length to maintain shape of the plant.
Light pruning of roses can be done during the summer to encourage additional flowering. As the blooms fade, cut the stem back to an outward facing bud to continue the V-shaped growth. Leaves below the flower have 3 leaflets, and those farther down the stem are composed of 5-7 leaflets. Always prune to a 5-7 leaflet bud, because those at 3 leaflets are more likely to lead to blind or non-flowering shoots.
Diseases and Insects
Unfortunately, roses are host to a wide range of insect and disease pests. Aphids, spider mites, leaf hoppers, scale and many others all feed on roses. Black spot and powdery mildew are prevalent diseases, but roses commonly get rust, canker, crown gall and several others.
Preventative sprays help reduce insect and disease pests. Several good sprays are available at nurseries and home and garden centers. Spraying should be performed on a weekly basis, especially during hot, humid weather. Spraying should be done during the cool part of the day to prevent burning the plant. A recommenced rule is to spray when the temperature in degrees Fahrenheit added to the relative humidity is less than 100.
Cultural methods will help reduce disease and insect problems. A healthy, well watered plant is less susceptible to problems and better able to withstand them when infected. Watering should be done early in the day and wetting the foliage avoided. Disease-infected leaves should be raked up and removed. Do not compost these leaves, because you will be returning the spores of the disease to the plants.