Are you searching for the best fertilizer for knockout roses?
A tried and true beauty of landscapes, the rose is one of the most widely cultivated garden shrubs. Known for their exquisite blooms and intoxicating fragrance the rose symbolizes love and passion throughout all cultures.
There are over one hundred species of rose known, and thousands of resulting varieties. Although they are popular as commercial cut flowers, roses are best known for their graceful beauty as outdoor ornamental flowers.
Proper care is essential to get the most out of your plants and produce the most beautiful flowers.
For that reason, in this post we are going to discuss what to look for in the best knockout rose fertilizer.
What is the best fertilizer for knockout roses?
Here is a quick preview of our top 4 picks
- Miracle-Gro Rose Plant Food
- Bayer Advanced All In One Rose & Flower Care
- Espoma Rose Tone
- Dr. Earth Total Advantage Rose & Flower Concentrate Fertilizer
How to choose the right fertilizer for knockout roses?
Knockout roses are a trademarked variety of shrub rose that was introduced in the year 2000.
They are incredibly easy to grow and have quickly become one of the most popular rose varieties grown in North America. They are heat tolerant and cold hardy, disease resistant and “self-cleaning”.
This means that they push the old blooms out-of-the-way when a new bud is formed, eliminating the need to deadhead spent flowers. The development of self-cleaning roses considerably reduced the amount of maintenance needed to be done by the homeowner to promote continuous blooming.
You may also enjoy reading: Should You Deadhead Knockout Roses?
Like most other flowering shrubs, knockout roses grow best when they are given the proper growing condition, including a regimen that provides proper fertilization.
In general, knockout roses are heavy feeders, requiring frequent feeding for optimum growth. “Heavy feeders” have a higher nutrient requirement than other plants usually due to fruit or blossom formation.
All plants have fifteen essential nutrients that are absolutely necessary for plant functions and growth: nitrogen, phosphorus, potassium, calcium, sulfur, magnesium, sodium, boron, chlorine, manganese, iron, zinc, copper, molybdenum and nickel.
Of the fifteen essential nutrients nitrogen, phosphorus and potassium are needed in the highest quantities.
Nitrogen will promote lush, green, vegetative growth; phosphorus strengthens the root systems and encourages beautiful blooms; potassium encourages vigorous growth and helps roses protect themselves from pest damage, drought, and cold.
To encourage strong, healthy knockout rose bushes teeming with blooms a well-balanced fertilizer (containing nitrogen, phosphorus, and potassium) should be applied to replenish nutrients in the soil.
The choice of an organic or inorganic/synthetic fertilizer lies in the hands of the gardener and their growing philosophy. The market is saturated with a variety of fertilizer options available for roses: organic, synthetic, granular, liquid, water-soluble, slow-release.
Regardless of the type of fertilizer purchased, it should be applied initially when there is 4-6” of new growth on the plants. For granular fertilizers, plant food should then be applied at the recommended rate every 4-6 weeks during the growing season after the initial application.
Liquid fertilizers are meant to be applied more frequently and are delivered at the time of watering.
No matter the type, remember fertilizers are essentially salts and need to be watered well into the soil to prevent damage to the to the roses’ roots.
Our top 4 picks
- Nutrient Ratio: 18-24-6
- Endorsed by the American Rose Society
Miracle Gro Rose Plant Food – An industry leader in conventional fertilizer products, Miracle Gro’s Rose Plant Food is a water-soluble fertilizer formulated specifically for rose bushes.
This rose food promotes beautiful blooms and lush foliage by immediately providing nutrients to the plants after application. With a nutrient ratio of 18-24-6 to encourage blossom development, dilute 1 tablespoon of the granules per 1 gallon of warm water to feed outdoor plants.
Miracle-Gro Rose Plant Food is endorsed by the American Rose Society and guaranteed not to burn rose bushes when used per the label instructions.
- Insect and Disease control up to 6 weeks
- Easy to apply
- Nutrient ratio 6-9-6
Bayer Advanced All In One Rose & Flower Care – An all in one product with proven results, the Bayer Advanced Rose & Flower Care delivers plant essential nutrients to roses while simultaneously providing insect and disease control for up to 6 weeks after application.
The easy to apply fertilizer granules should be sprinkled around the base of the shrub at a dosage recommended on the label, and then well watered into the soil to move nutrients to the root zone for plant uptake.
A nutrient ratio of 6-9-6 in Bayer Advanced all in One Rose & Flower Care provides a nearly balanced amount of nitrogen, phosphorus, and potassium for strong, healthy plant growth.
- All Natural Organic option
- 15 essential nutrients
Espoma Rose Tone – A fantastic all natural and organic fertilizer option which makes it a great option when searching for the best plant food for knockout roses.
Espoma Rose-tone provides gardeners with a long-lasting, premium plant food specially formulated for roses.
It contains all of the essential plant nutrients needed for plant functions and growth and is also enhanced with living microbes to increase soil quality. Espoma Rose Tone contains no sludges or other toxic ingredients making it environmentally safe.
For individual rose plants, sprinkle 1 ¼ cup around the base of each plant and work slightly into the soil. For rose beds, apply at a rate of 6 pounds per 100 square feet.
Water well after application to move nutrients to the roots of the rose bushes.
- Designed to promote larger and more abundant rose blooms
Dr. Earth Total Advantage Rose & Flower Concentrate Fertilizer – Formulated with proprietary PreBiotic® and ProMoisture Hydrate®, Dr. Earth Total Advantage Rose & Flower Concentrate is formulated to feed plants naturally and promote larger, more abundant blooms.
The patented PreBiotic® consists of soluble sugars to provide food to existing soil microbes while ProMoisture Hydrate® assists in the hydration of soil biotics, keeping them alive and hydrated in extreme heat or cold.
For optimum results, dilute 4 tablespoons of Total Advantage Rose & Flower Concentrate per gallon of warm water and apply to rose bushes at the rate on the label instructions.
When Is The Best Time To Feed My Knockout Rose Bush?
Now that we have narrowed down the type of plant food to use, let’s briefly talk about when to feed them.
The good thing to know about knockout roses is that is that they are very difficult to overfeed them, making them very easy to maintain.
Many people like to start by feeding them with a slow release fertilizer in early March. That way when they are ready for food in April the nutrients will already be in the soil ready to be absorbed.
If you don’t plan on using a slow release option and want to use a water-soluble fertilizer such as Miracle Grow. It is important to wait until the plant has gone through its first bloom cycle. After this, you can follow the instructions on the label of your preferred plant food.
Lastly, Knockout roses tend to slow down, early August. For that reason, discontinue using any plant food as they prepare for the fall season.
Very few plants can compare to the popularity and timeless beauty of rose bushes.
Known for their stunning blooms, exquisite fragrance, knockout roses have become a garden favorite in the last quarter century, now found in landscapes across almost all growing zones.
Their heat tolerance, cold hardiness, disease resistance, and self-cleaning ability make them easier to grow than traditional roses, needing less care from the home owner.
To garner optimal growth and blooms make sure to fertilize roses with a general purpose, balanced fertilizer or a plant food specific to flowering plants or roses to provide the essential nutrients these heavy feeding plants require for growth.
And most importantly, make sure to take the time to enjoy their delicate fragrance and gorgeous appearance!
What type of fertilizer do you use for knockout roses? Please share with us your thoughts on what is the best fertilizer for knockout roses in the comment section below.