When is the Best Time to Fertilize Roses?
Proper timing is crucial when applying rose fertilizer. Here’s a breakdown of the optimal times:
Established Roses
- Start fertilizing in spring when the first leaves appear and there is no longer a risk of severe frost, usually around April or May.
- Fertilize after each bloom cycle. For repeat-blooming roses, this can be every 4-6 weeks during the active growing and blooming stage, which generally runs from May to August.
- Avoid fertilizing after the end of July or August 15th, as this allows the roses to slow down their growth and prepare for winter.
Newly Planted Roses
- Start fertilizing about one month after planting, once the roses show some growth, indicating the roots are getting established.
What Types of Rose Fertilizers Should You Use?
Granular Fertilizers
- For established roses, use a balanced fertilizer like 10-10-10 (nitrogen-phosphorus-potassium). Apply about a cup of fertilizer per plant, scattered around the base and scratched into the moist soil.
- For newly planted roses, use a high-phosphorus, slow-release fertilizer to aid root development. A handful of bone meal can also be added.
Organic Fertilizers
- Organic options like compost, dried cattle manure, horn shavings, or Oscorna® rose fertilizer can be used. These are particularly beneficial in spring after pruning and in summer after the main bloom.
- Coffee grounds and eggshells can also be used as natural fertilizers, but ensure the coffee grounds are well-dried to prevent mold.
Liquid Fertilizers
- For foliar applications, use a dilute solution of fertilizer (e.g., fish emulsion) and add a mild soap as a surfactant. Spray until the liquid drips off the leaves, focusing on the underside where pores are more open.
How to Apply Rose Fertilizer Step-by-Step
-
Soil Preparation: Ensure the soil is moist before applying fertilizer. Water the roses well the day before fertilizing to prevent root burn.
-
Application Methods:
- For granular fertilizers, scatter the fertilizer around the base of the rose and lightly rake it into the soil. Keep the fertilizer away from the canes and graft union.
-
For liquid fertilizers, use a watering can, hose-end sprayer, or backpack sprayer to apply the solution directly to the foliage, especially in the morning to avoid burning the leaves.
-
Broadcasting and Watering In:
- After applying granular fertilizer, water the roses again to help the nutrients move into the root zone.
-
For foliar sprays, ensure the leaves are fully covered but not to the point of dripping excessively.
-
Post-Application Care:
- Avoid fertilizing on scorchingly hot days or when the soil is dry, as this can cause leaf burn or root damage. Water the plants thoroughly after fertilizing to help the nutrients reach the roots.
Environmental Conditions and Soil pH
- Temperature and Humidity: Avoid fertilizing in extreme heat or during periods of drought. Optimal fertilization occurs when the weather is mild and the soil is moist.
- Soil pH: Test the soil’s pH before applying fertilizer, as roses generally thrive in a slightly acidic to neutral soil pH (around 6.0-6.5). Adjust the fertilizer choice based on the soil analysis to ensure optimal nutrient absorption.
Reference:
[1] https://plantersplace.com/everything-roses/tips-for-fertilizing-and-watering-roses/
[2] https://www.rosen-tantau.com/en/advice-and-rose-care/fertilizing-roses-how-to-do-it-right/
[5] https://www.thespruce.com/how-when-to-fertilize-roses-4942489
