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. But, 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 ESTABLISHED ROSES:
Early to mid-spring: Begin fertilizing when new leaves emerge. Use a high-nitrogen fertilizer or top dress with alfalfa meal (5-1-2) for the first application to jump-start leaf development, along with epsom salts to encourage new cane development and lusher growth.
For best results fertilizing roses organically you need a combination of fish emulsion, blood/bone meal and alfalfa applied every 4 weeks in the growing season and occasionally add Epsom salts to stimulate basal breaks.
Mix equal parts of Miracle-Gro® Garden Soil for Roses (or Miracle-Gro® Garden Soil for Flowers) and the soil removed from the planting hole. If planting in a container, use with Miracle-Gro® Potting Mix. Either way, you are helping ensure that roses receive ample nutrition while establishing new roots in the garden.
Coffee grinds improve the soil around roses by fertilizing and enriching it. Roses require a neutral to acidic soil, and adding coffee grinds will help move the soil pH from neutral to acidic. Adding organic material to the soil will also improve drainage and aeration of your soil, which will benefit your roses.
Roses do like coffee grounds, but too much too close can give them a nasty nitrogen burn and can kill your roses. Never sprinkle coffee grounds right next to the plant. There's a great way to…
Helps With Nutrient Intake
"When rose plants have sufficient magnesium levels, they can more effectively utilize these nutrients, promoting overall growth and development." Additionally, Epsom salts' sulfur content also helps with nutrient uptake.
They are a fast-acting source for magnesium and sulfur. For soils on the alkaline side, the added sulfur is a benefit. Epsom salts, however, do not contain any of the three major components of most fertilizers—nitrogen, phosphorus or potassium—and therefore would not be a complete fertilizer for roses.
The Sin: Overfertilizing. The common misconception is that more fertilizer=more blooms, but roses only need so much fertilizer, and adding too much synthetic fertilizer can kill natural soil bacteria and/or lead to salt burn, which can both harm your plant.
Fertilize the perennial regularly throughout its growing season (about every two to four weeks depending on the type of fertilizer used). Stop feeding your roses in late summer when they begin preparing for winter dormancy.
Watch out for particularly prolonged dry spells. Newly planted roses – water every two or three days. Established roses – water once or twice a week as needed to keep the soil moist around your roses.
Watering early in the day allows the water to soak deeply into the soil and slowly dry up as the day goes on. In addition, morning watering allows the foliage of the rose to dry out in the sun, preventing powdery mildew or blackspot developing from wet conditions overnight.
Miracle-Gro® Water Soluble Rose Plant Food feeds instantly to grow bigger, more beautiful roses compared to unfed plants. Use with the Miracle-Gro® Garden Feeder or any watering can, and feed every 1-2 weeks.
If you are going to fertilize your roses in late August or September, use a low nitrogen mixture such as a 2-4-1 mix. Do not fertilize your roses with either a high nitrogen fertilizer or a balanced fertilizer (e.g. 10-10-10). The numbers are percentages of nitrogen, phosphorus and potassium respectively (N-P-K).
Epsom salt can improve the blooms of flowering and green shrubs, especially evergreens, azaleas and rhododendrons. Work in one tablespoon of Ultra Epsom Salt per nine square feet of bush into the soil, over the root zone, which allows the shrubs to absorb the nutritional benefits.
Baking Soda.
Dilute 1 teaspoon to 1 quart of warm, soapy water and spray on your roses' leaves. The baking soda will treat and prevent diseases like black spot, while the soap helps it stick, and is also mildly effective at smothering many insects pests.
Use a half cup to three-quarters of a cup of Epsom salts per plant. Do this in spring each year. Alternatively, water rose bushes with a solution of one tablespoon of Epsom salts per gallon of water. You can do this every couple of weeks throughout the growing season.
Beans and leafy vegetables. Coniferous trees. Tropical palms don't like Epsom salt, either. Insect-eating plants such as Pitcher plants, sundews and Venus flytraps are other plants that do not like Epsom salt.
Vinegar is known for its ability to lower soil pH levels. Since roses prefer slightly acidic soil, adding a small amount of vinegar to their water supply may help them thrive. In addition, using diluted white or apple cider vinegar as a spray on your roses can help control common garden pests like aphids.
Here's what I was going to write: Don't toss your banana peels into the Green Bin (or even the compost pile). Instead, chop them up and sprinkle them around your roses, to give the roses a good, organic snack of potassium.
Roses are among the plants that require a lot of calcium to grow well. Calcium is a secondary nutrient in terms of quantity required for plants, behind just nitrogen and potassium. Eggshells benefit roses by strengthening the cell walls of the plant's tissue, and they are primarily a great source of calcium.
As we've explained earlier, roses are one of those plants that would do a lot better when you use banana peels as fertilizer for them. The presence of not just potassium but calcium, iron, copper and manganese in banana peels is just too good a combination for roses.