Cultural Requirements of Roses

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Publication 506 - Also available in PDF form at http://www.wvu.edu/~agexten/hortcult/flowers/cultrose.pdf
Clifford W. Collier, Jr., Extension Specialist, Landscape Architecture
Revised by John Jett, Extension Specialist, Horticulture

Roses are perhaps the most popular garden flower grown in America and each year new varieties are introduced for the rose enthusiast. Roses do require constant and almost meticulous care if you want healthy plants which produce the desired flowers.

Soil

Roses will grow in a variety of soils provided they are well drained and have a high fertility level. If drainage is inadequate, you will have to install 3" agricultural drain tile.

Soil pH should average between 5.5 and 6.5. A soil test will determine the actual pH of the soil and whether lime or sulfur will be needed to correct its acidity.

Exposure

Good air circulation and full sunshine are important for growing healthy plants. Roses should be planted where air circulation is not hampered by screens, walls, fences, buildings, hedges or other plantings, and should receive a minimum of 6 hours of direct sunlight each day. If there is a choice, it is better for the plants to receive sunlight in the morning. In fact, by shading the plants from the hot afternoon sun, the colors of the flowers will hold up longer.

Fertilizing

Roses are heavy feeders, especially when in flower. They will not require additional fertilizer the first year if they have been properly planted in the spring. Roses planted previously will require two or three applications of a complete fertilizer during their growing season. Two to three tablespoons of 5-10-5 fertilizer per plant are applied in early spring after the winter protection has been removed and the plant is pruned to remove damaged wood. The second application should be made in June when the plant is in flower. If weather permits, a third application may be made before the middle of August.

Fertilizer should be applied when the soil is moist, being gently worked into the soil and then watered well. Caution should be taken not to let fertilizer come in contact with foliage or canes.

Watering

Frequent light sprinklings do more damage than good to roses. Roses should be watered only when needed and then enough should be applied to penetrate the soil to the depth of the root system, about one foot. Watering from overhead is not recommended as this only encourages the growth of fungus. Place the garden hose or soaker in the bed and allow the water to run slowly. It is also recommended that watering be done in the morning rather than the late afternoon or evening.

Mulching

The application of a mulch in the summer helps to conserve moisture and keep the roots cool. There are several good mulches, such as pine needles, buckwheat hulIs, ground corn cobs, and peat moss. Pine needles and ground corn cobs are good because they are loose and allow for better air circulation. Buckwheat hulls and peat moss should be worked into the upper two or three inches of soil. Buckwheat hulls are very light and may be blown away by even light winds. Peat moss must be kept damp. Otherwise, once it has become dry it is difficult to get wet again.

Mulches should be applied when the soil is damp and placed to a depth of about one to two inches. (Note that the soil should be tested every year or so, as mulches may alter the soil PH.) Also, additional nitrogen may be needed to replace that used by the mulch in the decomposition process.

Pruning

Pruning will vary with the type of roses grown, that is, climbing, polyantha, hybrid, teas, etc. There are, however, basic fundamentals which apply to all types. Pruning is done to remove old, weak and diseased wood, conflicting canes and to maintain the proper size and shape of the plant. During the first year after planting, it is important that the plant become well established, therefore the flowers should be removed as soon as they begin to fade.

Remove dead canes at the base of the plant and remove diseased or damaged wood to a point just below the damaged area and above a growth bud. Generally pruning is done in the early spring after the winter protection has been removed or when the buds begin to swell. Prune canes back to an outside facing bud so as to avoid crowding of branches in the center of the plant and to create an open center for the best Iight and air movement. Caution should be taken to leave at least three buds on each cane to insure good growth. This is especially true of hybrid teas, otherwise the plant will fail to grow and flower properly or may even die eventually.

Many roses, especially hybrid teas, have been grafted or budded on understock of a different species. It is important therefore that any growth below the graft or budding points be removed. The understock is often more vigorous in growth but with inferior flowers. If the plant has more than five good canes from the base, thin them by removing the weakest ones.

When pruning a rose, make a slanting cut no more than 1/4 inch above a growth bud. Make certain that the pruning shears are clean and sharp. Dull clippers cause jagged cuts favorable to fungus growth. Unclean shears may spread disease.

Pruning Tips:

Climbing Roses - During spring flowering, remove the oldest canes. Immediately after flowering, cut laterals back to a length of 6 to 12 inches.

Climbing Hybrid Teas - Little pruning required, except for thin, weak shoots. Do not prune severely before the plant is established or it may lose its climbing habit. After 2 years, some of the oldest wood may be removed.

Floribundas - Prune in the spring after the buds begin to swell, otherwise average pruning. Prune back to the second bud below the flower head.

Grandifloras - Prune same as for floribundas. Remove 2-year old canes, leaving 3 to 4 buds from the base of the plant.

Hybrid Perpetuals - Prune as for fIoribundas. In early spring, remove all dead, weak or injured growth and then thin to leave 4 to 8 vigorous well spaced shoots. These may be cut back to 2-3 feet from the ground or to any greater height at which one desires to view the flowers.

Hybrid Teas - Moderate to light pruning recommended.

Polyanthus - Little pruning required. In the spring remove old canes and those which failed to bloom the previous year.

Ramblers - Prune immediately after flowering to remove old and recently flowered wood. Prune vigorously. Leave new shoots unpruned except for dead and diseased wood.

Shrub - Prune to remove dead and diseased wood.

Cutting Roses For Indoor Use

Roses should be cut in the early morning. Make the cut 1/4 inch above an outward pointing leaf bud, making sure to leave at least 3 leaf buds on the cane.

Insect and Disease Control

A regular maintenance program should be established for protection against infestation and attack by insects and diseases. Local garden center operators, nurserymen or county extension offices should be consulted for latest recommendations and available publications.