Garden roses grow best in slightly sandy soil. They like a pH range between 5.5 and 6.5. Have your soil tested to find out whether the acidity is within this range. The soil test also states the content of soil nutrients. If you need fertilizer, the report recommends how much and what kind to use.
The fertilizer elements most likely to be needed in rose beds are nitrogen (N), phosphorous (P), and potassium (K). If you don't have your soil tested, apply a complete fertilizer. Examples are 5-10-5, 4-8-4 or 4-8-6.
- Apply fertilizer to rose beds at the rate of three pounds per 100 square feet. This is about one-quarter cup of dry fertilizer per plant.
- Spread the fertilizer evenly around the plant. Scratch it into the soil's surface.
- Then water the roses.
When to fertilize
- Apply fertilizer in May when you see new growth. Wait until all danger of severe freezing is past.
- Fertilize a second time when the first flower buds set.
- Apply a final fertilizer in mid-July.
- Do not fertilize roses after mid-August. Late season fertilization may cause the rose to keep on growing. This could delay hardening in the fall and lead to winter injury.