What Type of Fertilizer Do Roses Need?
Roses require a balanced blend of the three primary macronutrients – nitrogen (N), phosphorus (P), and potassium (K) – along with several micronutrients to thrive. The ideal N-P-K ratio for roses varies depending on the growth stage and time of year.
How Much Fertilizer Should I Use for Newly Planted Roses?
For newly planted roses, use a slow-release fertilizer with a balanced N-P-K ratio, such as 10-10-10 or 5-10-5. Apply a handful of bone meal around the base of the plant to promote root development. Additionally, mix in 1/4 to 1/2 cup of Epsom salts to provide magnesium for new cane growth. During the first growing season, use a liquid fertilizer like fish emulsion every 3 to 4 weeks to avoid burning the tender roots.
How Much Fertilizer Do Established Roses Need?
Early to Mid-Spring
Apply a high-nitrogen fertilizer (e.g., 5-1-2 or alfalfa meal) to encourage leaf growth, along with Epsom salts for new cane development. When the shoots are 4 to 5 inches long, add a slow-release balanced fertilizer.
Throughout the Growing Season
Fertilize every 2 to 4 weeks with a balanced fertilizer (e.g., 10-10-10 or 15-10-10). For repeat-blooming roses, continue this frequency during the blooming season.
Late Summer to Early Fall
Use a slow-release fertilizer with low nitrogen content, such as bone meal or rock phosphate, to promote root growth and next year’s blooms.
How Often Should I Fertilize Roses?
- Liquid Fertilizers: Apply every 3 to 4 weeks during the growing season, following the package instructions for the correct dilution ratio.
- Granular Fertilizers: Apply every 4 weeks during the growing season, using about half a cup per plant and following the directions on the label.
- Organic Fertilizers: Use aged or composted manure, bone meal, or dried blood meal, applying a heaping tablespoon around each plant.
Soil pH and Nutrient Levels
Roses prefer a slightly acidic to neutral soil pH between 6.0 and 7.0. Conduct a soil test every 3 to 5 years to determine the soil’s pH, structure, and nutrient levels, which will help you choose the best amendments and fertilizers.
Additional Considerations
- Avoid fertilizing during extreme heat to prevent stress, and stop fertilizing 6 to 8 weeks before the average first frost date to prevent new growth from being damaged.
- Water roses before and after fertilizing to deliver nutrients efficiently and prevent root burn.
- Apply foliar sprays early in the day to allow leaves to dry out and prevent disease.
By following these guidelines on the type, quantity, and frequency of fertilizer application, you can ensure your roses receive the optimal nutrition for healthy growth and abundant blooms.
