By Dr. William C. Welch
Professor and Landscape Horticulturist
Texas A&M University, College Station, Texas
If planting only a few roses, dig individual holes for them. Holes should be at least 12 inches deep and 18 inches wide. Mix about one-third organic material (peat, pine bark, or compost) with some of the soil from the hole, along with a gallon or two of well-rotted cow manure, if available. A half-cup of bone meal or superphosphate, thoroughly mixed with the soil, is a good addition. A similar amount of agricultural gypsum is beneficial for heavy clay soils.
Soil preparation can be done just prior to planting, but is more effective if completed several weeks or months before planting.
Spacing of the plants will vary with varieties. Most Polyanthas can be planted as close as 18 to 24 inches, while Chinas, Bourbons, Teas, Hybrid Perpetuals, Hybrid Teas, and Hybrid Musks are best at a 3- to 5-foot spacing, depending on the variety. Climbers and ramblers need more space to develop their potential. Eight to 10 feet is appropriate for most, but under good growing conditions, Banksias, Cherokee, and certain others could be spaced at 15-foot intervals.
Bare-root plants should be set out as soon after receiving them as weather and time allow. If a delay of more than a few days is necessary, remove the plants from the shipping bag and 'heel them in' by covering the roots and part of the tops with loose soil. Container-grown plants may be set out at any time, but most rose growers avoid the hot summer months, when extra irrigation and care may be necessary to insure success. Prune tops back an inch or two to just above a live and healthy bud on each cane. Cut back canes or roots damaged in shipping or handling to healthy tissue. Dig the hole large enough to accommodate the natural spread of the roots, and fill with the soil mixture described earlier. Firm the soil well around the roots, and water thoroughly to remove air pockets and settle the soil firmly around the root system. Set plants at approximately the same level at which they had been growing, or slightly deeper.
Roses are heavy users of nutrients and require frequent application of fertilizers. To determine fertility of existing soil, contact your county Extension agent for instructions on submitting a soil sample.
Do not apply fertilizers until the first set of flowers begins to fade for everblooming types, or in the case of once-blooming roses, 8 to 10 weeks after planting. A heaping tablespoon per plant of a complete fertilizer, such as 6-10-4 or 8-8-8, may be applied every 4 to 6 weeks until about September 1. Application after that time can promote soft fall growth that may result in freeze damage. The time-honored fertilizer for roses is well-rotted cow manure. Since manure may not be available, commercial fertilizers have become popular. Phosphorus is the material that helps plants develop strong, healthy roots and prolific flowering. Superphosphate is usually available, and can be applied at the rate of 3 to 4 pounds per 100 square feet. Since phosphorus is not very mobile in the soil, it should be well mixed during preparation.
Nitrogen is easily and quickly depleted from the soil, and needs to be applied periodically during the growing season. It is necessary for more and bigger canes, stems, and leaves. Slow-release commercial fertilizer or natural materials, such as cottonseed meal, last longer and require fewer applications through the growing season.
Potassium is needed for promotion of new growth, disease resistance, and cold tolerance. All 3 nutrients (nitrogen, phosphorus, and potassium) are included in balanced fertilizers. Many rose growers apply a balanced fertilizer every 4 to 6 weeks during the growing season.
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