Culture and Production of Roses, Part 2 Planting

Planting

Container-grown plants are a better choice for late planting.

Spacing the plants in the rose bed depends on the variety and the growth rate. An average spacing is 3 to 4 feet apart. A 5- to 6-foot spacing is recommended for vigorous growing varieties.

Dig a hole large enough to accommodate the root system without crowding. Planting depth is critical. Plants set too deeply do poorly and are more susceptible to pests.

To set the plants at the correct depth, construct a cone-like mound of soil in the middle of each hole. The cone should be high enough so when the plant is set on top, the level of the graft union (the swollen area of the main stem) is about 1 inch above the soil level. Separate and spread the roots around the cone (Figure 4). Partially fill the hole with soil, shaking it between the roots. When the roots are covered, fill the hole with water and allow it to soak into the soil. Then finish filling the hole. Use your hands to build a ring of soil about 4 inches high along the perimeter of the planting hole. This directs water to the roots while the plant is getting established. Water thoroughly several times to settle the soil around the roots.

After planting bare-root plants, prune the canes back to 5 to 7 inches in height. Remove any broken or discolored canes. In the colder, mountainous region of Georgia, mound soil up over the canes to protect them from cold damage during the winter. Remove the mounded soil as soon as the danger of frost has passed or as new growth begins.

Plant container-grown roses no deeper than they were in the original container. If the root system is pot-bound, loosen it with your hands before planting.

Plant individual plantings similar to bedded plants. Dig the planting hole two to three times wider than the root system and 12 to 15 inches deep. This loosens the soil in a large area and provides a favorable environment for root system growth. A successful rose grower never places a 10-dollar plant in a 2-dollar hole.

Mulching

Mulched rose plants have several advantages over those grown in bare soil. Mulching prevents soil crusting and erosion, maintains a uniform soil temperature, conserves moisture and reduces weeds.

Mulching materials include fall leaves, pine straw, ground pine bark and hardwood chips. Your choice depends on cost, availability and ease of handling. A 2- to 3-inch layer of mulching material is adequate. Too much mulch causes soil to retain excessive moisture.

Watering

Adequate soil moisture is essential for rapid, healthy cane growth and flower development. During dry weather, water mulched roses at least once a week. Unmulched plantings require more frequent watering. Three to five gallons of water per plant at each watering should adequately wet the root zone.

Avoid using lawn sprinklers or other overhead irrigation devices that wet the foliage and encourage leaf diseases. A soil-soaker hose placed under the mulch is ideal for watering roses. Drip or trickle irrigation kits are also excellent irrigation systems for rose plantings.

Fertilizing

Fertilization varies widely, depending on plant size, soil type, rainfall and the time of growing season. Many rose growers have developed their own recipe for fertilization based on past experience or the experiences of others. This has led to many different approaches to rose fertilization.

Light fertilizer application at monthly intervals are recommended. A 12 to 16 percent nitrogen source such as 16-4-8 or 12-4-8 fertilizer is advisable. Three tablespoons per plant per application is usually adequate. If the plant is shorter than 1 foot, reduce the rate to 1 tablespoon. Large bushes, 6 feet tall, respond to 5 tablespoons per application. Beginning 6 inches from the main stem, spread the fertilizer evenly in a circle around the shrub. Use a rake to mix it lightly into the soil and water soon after application. Avoid getting fertilizer on the foliage, canes or flowers and too close to the main trunk.

Pruning and Grooming

Roses respond to pruning and grooming (removal of old flowers) by producing specimen flowers in greater quantity. Larger, more attractive flowers are the result of well-groomed, correctly pruned plants. Major pruning is done in early spring (before growth begins) while grooming is done throughout the growing season.

All plants are not pruned alike because of differences in flowering and growth habits. Generally, weak-growing varieties are pruned lightly while vigorous growing varieties are pruned more heavily and more frequently. In either case, wounded or weak canes or those showing evidence of bark splitting should be removed first.

Here are specific instructions for pruning the various types of roses:

Hybrid Teas – Hybrid teas (garden type or cut-flower roses) should be pruned in early spring just before new growth starts. Leave at least four to six of the most vigorous canes. Prune these canes back to within 24 to 30 inches of ground level. Make the cuts about ¼ inch above a bud. Always use clean, sharp pruning shears. Keep all spinkly growth removed. When spring growth begins, remove all but four or six of the healthiest canes. Cut the remaining canes one-half their length.

Vigorous shoots (suckers) originating below the graft union will be different in foliage and flower from the desired grafted variety and should be removed. If allowed to develop, they will compete heavily with the grafted variety.

Groom the plants by removing old flowers as soon as they have passed their peak. If allowed to remain on the plant, the flower heads will develop seed pods (also called hips) that draw heavily on the plant’s food supply. Also, remove any spindly shoots or sucker originating from below the graft union or any stems showing disease symptoms during the growing season.

To produce specimen flowers on hybrid tea or garden roses, remove the flower buds that develop on shoots other than the main one. Allow only one flower bud to develop and mature on each main shoot. For larger, quality blooms for exhibition or show purposes, always remove all but one bud per stem. Pinch or prune the extra buds while they are young and soft.

Climbing Roses – Climbing roses require special pruning for profuse flowering. Many varieties in this group produce most of their flowers in the spring. During flowering, they will develop new canes on which next year’s flowers will be borne. Prune to remove the oldest canes near ground level immediately after flowering to promote vigorous new shoot development.

Prune climbers to keep them trained to their support (fence, trellis, wires). Climbers generally require much less pruning than do other types.

Some climbers bloom off and on during the spring and summer. However, they usually have a peak flowering period quite early in the season. Prune these climbers following their first flush of flowering).  Prune climbers after the first flush of flowers. Keep weak, diseased or dead stems removed. Leave five or six healthy, vigorous canes. Thick, dense growth of climbers leads to problems.

Canes of most climbers are good flower producers for two years. In some cases, new canes develop only on the older canes rather than from ground level. In such cases, remove the oldest canes in early spring, leaving five or six of the healthy, vigorous ones. Also, keep all faded flowers cut from the plants.

You can now get climbing forms of many hybrid tea varieties, which are generally more vigorous than their corresponding bush varieties. Prune them in early spring to remove weak, spindly growth and dead or diseased branches.

Floribundas and Grandifloras – Floribundas and Grandifloras are grouped together for practical purposes. Both produce flowers in profusion. Floribundas have a shrub growth habit and are low- to medium-growing. Consequently, pruning is generally confined to maintaining plant shape and vigor. Grandifloras have a growth habit similar to that of hybrid teas and are pruned in the same manner.

Cutting Roses

Cut roses in early morning or late afternoon when there is more stored food in the stems and flowers. Stored food lengthens the life of the cut flower. Make cuts about ¼ inch above a node and cut only the length of stem needed for the flower arrangement.

Put the cut stems in water as soon as possible. Have a bucket or container with you in which to place each stem as it is cut. Put the bucket of cut roses in a cool, dark place for several hours. If room permits, place them in the lower part of your refrigerator. Unopened flower buds can be stored in the refrigerator for several days until blooms are desired for special occasions.

Controlling Pests

Roses will not be productive during the flowering periods unless they are kept free of insects and diseases. It is important to understand the characteristics and the types of damage caused by insects and diseases.

Before applying any pesticide, always read and follow the instructions on the label. Play it safe! Do not expose yourself or your plants to unnecessary hazards such as improper measuring, mixing and application of insecticides and fungicides.

Careful observation of your plants throughout the year is of utmost importance. This allows early detection of problems that may arise and leads to better control, better plants and greater personal satisfaction.

Successful rose growers prevent problems more often than they control them. Here are a few tips that will help keep your plants beautiful, vigorous and productive:

  1. Buy healthy plants. Avoid those with any abnormal swellings or discoloration on canes or roots. Do not, however, confuse the enlarged graft union with a disease.
  2. When applying fungicides, always spray the area underneath the plant where leaves have fallen. This will help in your disease control program.
  3. Cut out any canes showing cankers, discolorations or sunken areas. Make cuts 4 to 6 inches below the infected area. Before making each cut, dip shears in a solution of rubbing alcohol or a solution of 9 parts water and 1 part bleach. Destroy all infected stems, leaves and faded blooms.
  4. Remove and destroy any plant infected with crown gall or root-knot nematodes. Do not replant on such sites if at all possible.
  5. Successful rose growers follow a regular spray program. Generally, each application contains a fungicide for disease control and an insecticide for insect and mite control. Applications are usually made at weekly intervals or as indicated on the pesticide label. Preventive spraying is the most effective approach to controlling pests.

Leaf diseases are extremely difficult to control once they have become established. When applying fungicides, cover the surfaces of stems, leaves, flower buds and canes thoroughly to adequately control pests. Do not delay spraying even if rain is forecast. Most disease-causing organisms require this wet environment to infect; this is the time fungicides are needed the most.

For more info, contact:

Dept.of Agriculture
D.A. Compound, Elliptical Rd., Diliman,Quezon City
Tel. Nos. (632) 929-6065 to 67 / 920-3991 / 928-1134
Web: www.da.gov.ph

source: pubs.caes.uga.edu, photo from cherryvalleynursery.com

 

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