Roses are traditional denizens of the spring and summer garden, and bring with them lush green growth and colorful, fragrant blooms. These are high-maintenance plants, though, and require careful placement, watering and nutrition to thrive. Zone 9b provides warm, bright summer conditions but also presents some challenges where roses are concerned.
Once of the most important aspects of growing roses is site selection. According to the University of Illinois, roses require at least six hours of sun every day, though they will grow in partial shade in warmer areas like zone 9b. Lack of sunlight may lead to leggy roses that are all stems and no leaves, however.
Roses need quick-raining soil to keep them from sitting in standing water. The University of Illinois states that poor drainage leads to leaf dieback and rose death, and suggests loose, porous soil for roses. In zone 9b, where increased waterings are necessary during summer, this mixture helps retain moisture without holding standing water.
Roses are heavy feeders and require consistent sources of hearty nutrition for both leaf and flower growth. Rose bushes need enough organic fertilizers like organic compost, fish emulsion, bone meal and blood meal, which add nutrition to the soil and provide long-term sources of vitamins and minerals.
According to Rose Magazine, fertilizer choice depends largely on what the gardener wants from her roses. Nitrate-heavy synthetic fertilizers lead to quicker foliage growth, so rose-specific fertilizer, 10-10-10 fertilizer or 12-12-12 fertilizer encourages lush, green rose leaves, but may not do much for rose blooming.
University of Illinois suggests two to four applications of synthetic fertilizers every season: one in spring, with one to three more applications spread through summer into fall. Organic fertilizers are gentler, and safe for more frequent use.
In zone 9b, where summer temperatures may rise over 100 degrees Fahrenheit, water should always accompany fertilizer applications. The water helps the fertilizer soak in, and nurtures the rose with the moisture it needs. In zone 9b, roses should receive 2 to 3 inches of water a week, divided into three to four applications.