What Types of Fertilizers are Best for Roses?
Roses require a balanced fertilizer that includes nitrogen (N), phosphorus (P), and potassium (K), along with micronutrients, for optimal growth and blooms.
Organic Fertilizers
- Aged or composted manure is excellent, but ensure it is not fresh to avoid burning the roots. Apply about 2-3 inches deep.
- Bone meal adds phosphorus; mix it deeply into the soil to prevent wildlife attraction and ensure slow release. Use about a heaping tablespoon per rose plant.
- Dried blood meal is a good source of nitrogen; apply about a tablespoon around each plant, avoiding excessive use to prevent root burn.
Inorganic Fertilizers
- Special rose fertilizers with high phosphorus ratios such as 18-24-16, or general complete fertilizers like 5-10-5, 4-8-4, or 4-12-4 are recommended. Follow the label instructions for application amounts, typically half a cup per plant.
When is the Best Time to Fertilize Roses?
- For newly planted roses, focus on phosphorus-rich fertilizers to promote root growth.
- For established roses, fertilize several times throughout the spring, summer, and fall, especially for repeat-blooming varieties like hybrid tea roses. Start fertilizing when you see 4-6 inches of new growth and the first real leaflet with 5-7 leaves.
How Often Should Roses be Fertilized?
Granular Fertilizers
- Avoid using granular fertilizers during the first growing season to prevent burning the fine roots. Instead, use liquid fertilizers during this period.
- For subsequent growing seasons, apply granular fertilizers every 4 weeks throughout the growing season.
Liquid Fertilizers
- Use liquid fertilizers every 4-6 weeks during the blooming season. This is particularly recommended for roses grown in containers, which need more frequent fertilization.
How Much Fertilizer Should be Applied to Roses?
- For granular fertilizers, use about half a cup per plant, following the label instructions.
- For liquid fertilizers, follow the product’s instructions, typically applying every 4-6 weeks.
How to Adjust Fertilization Based on Soil and Plant Needs?
- Ensure the soil pH is between 6.0 and 6.5 for optimal nutrient uptake. Adjust the pH if necessary.
- Conduct a soil test to determine the precise nutrient requirements and adjust the fertilizer accordingly.
- Monitor the plant’s response to fertilization and adjust the fertilizer ratio based on observations, such as too much nitrogen leading to lush foliage but few blooms, or too little nitrogen resulting in yellow leaves and no new growth.
Best Practices for Watering Before and After Feeding Roses
- Water the roses thoroughly before and after applying fertilizer to prevent burning the roots. Ensure the soil is moist but not waterlogged.
- Avoid fertilizing during extreme weather conditions such as heavy rain, intense heat, or just before a frost. Stop fertilizing 6-8 weeks before the first typical frost date.
Reference:
1. The Spruce: How and When to Fertilize Roses
2. Heirloom Roses: Fertilize Roses
3. Martha Stewart: How and When to Fertilize Roses for Vibrant, Beautiful Blooms
