Fertilizing roses in the spring
Blaze climbing rose
I saw my first rose bloom on April 1. It was not an April Fools’ prank but a result of our warm spring weather. Flowering is about four to six weeks ahead of schedule. Of course we all want these beauties all season long. If so, then you need to provide an extra boost through fertilization. Proper fertilization develops strong vigorous canes that produce big, fat plump buds with nice flowers.
Most local soils have plenty of phosphorus and potassium, so the recommendation of using a balanced fertilizer such as 13-13-13 or 10-10-10 is outdated. The old recommendation was to apply about 1 cup of this type of fertilizer per plant three to four times per growing season, between mid-April and mid-August.
Newer recommendations are more environmentally friendly, as it reduces the use of fertilizer containing unnecessary phosphorus and potassium. Nitrogen, the first number on a bag of fertilizer, is the key nutrient for established roses. Using a higher rate of nitrogen and lower amounts of phosphorus and potassium are best. Examples of fertilizers to use are 27-3-3 or 25-5-5. (Hint: Many rosarians just use plain, inexpensive lawn fertilizer.) Instead of using the one cup rate, use only about 1/8 to ¼ cup per plant, following the same application schedule listed above. This supplies the same amount of nitrogen as the traditional application, but does not build up high and unnecessary levels of phosphorus and potassium.
Landscape or shrub roses may really not need any additional fertilizer. These plants are more vigorous than the old hybrid tea types. As a result, they will normally flower all summer long on naturally occurring nutrients in the soil. If you like, they can be given a post-winter boost with a mid-April application to get the plants off to a good start.
For the organic growers, blood meal is an excellent rose fertilizer. Blood meal is higher in nitrogen while being low in the phosphorus and potassium. You can apply about a cup or so each time to provide about the same rate as man-made fertilizers.
Fertilizer should be placed out and around the plant, at the drip line where the roots are found. Avoid placing the fertilizer at the base of the plant. Be careful when working the fertilizer into the soil. Do not dig deeply into the soil as this will damage the rose roots. If the plants are mulched, pull it away, apply the fertilizer and then replace. Important Note: Be sure to water the fertilizer into the soil immediately after application to avoid burning and damaging the plant.
Complete these simple steps and your roses should reward you with a beautiful bounty of blossoms all summer long. Since it appears it has arrived many weeks ahead of schedule, let’s hope for the best this summer and that we all don’t cook and fry!
Tina Scarpelli McGugan
1 year, 2 months agoI haven’t had a bloom yet, but some of my Knockouts are full of aphids already. This is the first time I have ever had to deal with aphids on those roses!
Dennis Patton
1 year, 2 months agoAphids are just horrible on roses this spring all over the growing tips. For control, use a strong spray of water, Insecticidal Soaps or a chemical spray.
With the mild winter this could be just the first of many insects outbreaks this year.
Dennis - Johnson County Extension