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How to Fertilize Roses for Beautiful Flowering Bushes

When and How to Apply Organic and Inorganic Rose Fertilizers

Rose bush with bright red flowers in backyard garden

The Spruce / Candace Madonna

An important part of caring for roses fertilization. These flowers are heavy feeders so administering rose fertilizer regularly and properly is crucial. Roses need the three main macronutrients for plants—nitrogen (N) for foliage growth, phosphorus (P) for root growth, and potassium (K) for flower formation—plus various micronutrients, including iron, calcium, and magnesium.

Below, find a complete guide to fertilizing your roses, including the best time of year to fertilize roses, how exactly to fertilize the bushes, plus how to use organic or inorganic fertilizer.

Tip

To have a baseline and take the guesswork out of which nutrients and how much the soil needs, it’s always a good idea to get your soil tested. A soil test will also tell you whether the soil pH is suitable for roses. Roses prefer neutral to slightly acidic soil with a pH of 5.5 to 6.5, so to avoid growing problems, you might have to raise the soil pH by adding limestone.

How and When to Fertilize Roses

When to fertilize roses and how much fertilizer to use depends on the type of rose and the length of its growing season. Tea roses, for instance, require more nutrients than shrub roses. It’s helpful to keep a record of when you fertilize your roses using a calendar or a task reminder app. Here are some guidelines.

Newly Planted Roses

  • Amending the soil of the planting hole with rich organic matter before fertilizing will create a nutrient-rich environment for your roses.
  • To aid in root development, gently incorporate a slow-release fertilizer as recommended by instructions, combined with a handful or so of bone meal.
  • Use 1/4 to 1/2 cup of Epsom salts sprinkled around the base of the plant. This will promote foliar and cane development.
  • Newly planted roses should only be fertilized with phosphorus to encourage the development and establishment of the roots. Wait until the rose has bloomed before adding any other fertilizer.
  • As the roses are establishing, continue to fertilize every 3 to 4 weeks but only with a mild fertilizer such as fish emulsion.

Warning

Avoid using full-strength fertilizers on newly planted rose bushes. It could dry out the plant and cause leaf margins and root tips to burn.

Established Roses

  • Start fertilizing when the first leaves appear and there is no more danger of severe spring frosts. After that, the fertilization schedule should be based on how long and how often the rose is blooming.
  • A rule of thumb is to fertilize after each bloom cycle but to gradually reduce the amount of fertilizer by half each time. Stop fertilizing six to eight weeks before the first average frost date in your area. This prevents the plant from producing large amounts of new soft growth late in the summer, which can be damaged by cold weather in the fall and winter.
  • After the roses have gone dormant, you can fertilize them again. Adding fertilizer will not harm the plants at this point but will get them ready for the next spring.

Container Roses

  • To sustain their beautiful blooms, roses need plentiful nutrients. Since regular watering tends to wash nutrients out of pots, these roses may need more frequent fertilizing than those growing in the garden.
  • Check regularly on the foliage. If it starts to look a bit chlorotic (yellow leaves), this indicates a nutrient deficiency and it would be time to feed the plant in addition to the intervals described above.
  • When initially planting your roses into containers, mix a slow-release granular rose fertilizer into the potting soil and add your bone meal to aid in growing healthy roots.

The Difference Between Organic and Inorganic Fertilizer

There are two basic types of rose fertilizers, organic and inorganic. Most organic fertilizers are naturally released into the soil more slowly and over a longer period than inorganic fertilizers. The exception is inorganic controlled-release fertilizers, which release nutrients over several months depending on soil moisture and temperature.

Using Organic Rose Fertilizers

Aged or composted manure, worked into the soil about 2 to 3 inches deep, is an excellent source of all three macronutrients, N, P, and K. Always make sure the manure is “aged,” i.e. not fresh, otherwise it has a high nitrogen content that will cause fertilizer burn in the plants.

Bone meal adds phosphorus to the soil. Mix it deeply into the soil, not only because it does not enter the soil easily with watering but also to prevent wildlife from being attracted by the smell and digging up the soil. Add a heaping tablespoon per rose plant.

Dried blood meal is also a good source of nitrogen. Apply about a tablespoon around each plant. Too much nitrogen can burn the roots so don’t apply more than needed.

If you don’t mind the smell, liquid fish fertilizer or fish emulsion, diluted in water according to the product label, is a fast-release organic source of nitrogen.

Other organic fertilizers include:

  • Greensand for potassium and micronutrients
  • Rock phosphate for phosphorus, calcium, and micronutrients
  • Alfalfa meal as a balanced fertilizer
  • Seaweed for nitrogen and phosphate
  • Coffee grounds sprinkled at the base of the bush for a nitrogen boost

Tip

Epsom salt is often praised as an organic fertilizer and pesticide. However, the use of Epsom salt as a rose fertilizer to supply the soil with magnesium should only be considered if a soil test shows a magnesium deficiency or if the plant is just getting going. Applying too much Epsom salt when the soil is not in need of magnesium can harm the plant.

Rose bush
Rose bush Thomas Winz / Getty Images 

Using Inorganic Rose Fertilizers

There are special rose plant foods that are tailored to the higher phosphorus needs of roses, with an N-P-K ratio such as 18-24-16. However, you don’t necessarily need to get a special fertilizer for your roses. You can also use a general complete fertilizer with a high phosphorus ratio, such as 5-10-5, 4-8-4, or 4-12-4.

For the amount, follow the directions on the fertilizer label. The general rule of thumb for complete fertilizer is half a cup per plant.

Since inorganic fertilizers are more concentrated than organic fertilizers, don’t pile them up on dry soil, which can cause burning. Instead, spread the fertilizer thinly and evenly around the plant and lightly rake it into the damp soil. The best time to apply the fertilizer is before it rains or watering. Keep the fertilizer away from the canes and the graft union, and water the plants well after applying fertilizer.

The rule of thumb for controlled-release fertilizer is about half a cup per plant unless specified otherwise on the product label.

Always water roses after applying fertilizer
Always water roses after applying fertilizer mustafagull / Getty Images

Tips for Fertilizing Roses

  • Soil pH affects how roses absorb nutrients, so always test the soil's pH before applying fertilizer.
  • Keep to a regular fertilizing schedule.
  • Water roses deeply before and after fertilizing to prevent root burn or shock. 
  • Apply foliar sprays to roses in the morning. 
  • Avoid fertilizing your plants in extreme heat.
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Quick Guide to Fertilizing Plants. University of Minnesota Extension.

  2. Roses: Care After Planting. University of Missouri.

  3. When and How to Fertilize. Marin Rose Society.

  4. Quick Guide to Fertilizing Plants. University of Minnesota Extension.