Liquid Rose Fertilizer vs. Time-Release Granules

Need for Fertilization

• Horticulturists consider roses "heavy feeders," meaning these plants grow and flower better if the soil is rich in nutrients. Roses grow best in an organic-rich loamy soil that has good drainage. Adding compost, rotten manure or other organic materials to the soil improves soil fertility and makes clay soils more porous for better drainage and sandy soils more fertile and moist. Organic matter continually breaks down across the year to release nutrients for rose's roots to absorb. Depending on the garden soil, verified with a soil test, applying supplemental fertilizers ensures the rose bushes grow to their fullest potential.

Fertilizer Insight

• Organic and synthetic, slow-release fertilizers are safer to use on plants. Fertilizers are a mix of nutrients, often in the form of salts. If fertilizer is applied incorrectly, such as in an overdose, rose plant roots may be damaged or killed from the burning effects of fertilizer salts. Slow-release or "time-release" fertilizers slowly weather away to release nutrients over a multiple month-long time frame. Liquid fertilizers, also called water-soluble fertilizers, immediately increase nutrient and salt levels in the soil. Liquid fertilizers leach through the soil more quickly, especially in regions with lots of rain or with sandy garden soils.

Slow-Release Granules

• For the novice gardener, or person more interested in the lowest maintenance possible in a rose garden, stick with slow-release fertilizer products. A well-balanced, all-purpose garden fertilizer formula usually suffices, such as 10-10-10. However, designated rose fertilizers work well, as they may have proportions of phosphorus, potassium or micronutrients for specific use on roses. Always follow product label directions for dosage and timing. Typically, scattering slow-release granular fertilizer around roses every four weeks from mid-spring to late summer -- when leaves are present -- suffices in temperate parts of the United States. During the hottest times of the summer, less fertilizer is used but irrigation increases, according to the American Rose Society.

Liquid Fertilizer

• Liquid rose fertilizers often have the same nutrient formulation as the slow-release types. If you want extra-large or abundant growth and flowering on roses, liquid feeding in addition to slow-release fertilization is worthwhile. Relying solely on liquid fertilizing roses is problematic, as water-soluble fertilizers leach quickly and create uneven levels of nutrients in the soil profile. Once leaves appear on the roses in the spring, until late summer, liquid fertilizers may be applied to fertile, organic-rich rose garden soil in two-week increments. Follow label directions for dosages and apply the solution to the soil, not the leaves. Wet rose leaves are more susceptible to fungal diseases. If the liquid fertilizer is a type that is absorbed by the foliage, apply it in the early morning so the leaves fully dry before sunset.