Roses are heavy feeders that require a broad spectrum of nutrients throughout the growing season to produce the best blooms. Therefore using a range of organic fertilizers on your rose bed delivers the best results.
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. Different organic fertilizers stimulate the soil ecology and provide all the nutrients roses need to grow strong and healthy with plentiful flowers.
Natural, organic fertilizers act like a healthy balanced diet whereas chemical fertilizers are like multivitamins which provide a boost of nutrients but do nothing to stimulate the soil ecology and do not add to the long term fertility of the soil.
Organic, natural fertilizers such as alfalfa, fish emulsion, regular mulch, and blood/bone meal are better for the environment as they, not only directly feed the rose but improve the long term health and fertility of the soil too.
1. Mulching as Fertilizer for Healthy Roses
Applying mulch around the base of roses twice a year is the best way to maintain soil health and add nutrients to the ground organically.
Adding mulch to the rose bed is more about feeding the soil itself rather than directly feeding the plant, which in turn produces healthy, disease-resistant roses.
Leaf mold, well-rotted horse manure, worm castings, grass clippings, and compost are all good choices as they not only add nutrients but also improve the soil structure and feed the soil’s ecology.
Well-rotted horse manure is particularly good for enriching the soil as it is packed with energy and contains phosphorous, nitrogen, potassium, and phosphate, all of which are required for growing healthy roses.
The manure breaks down slowly and releases its nutrients over time so that water-soluble ingredients such as potassium are added to the soil gradually and not washed away by the first spell of heavy rain as they are with chemical fertilizers.
Manure reinvigorates the microbes, beneficial bacteria, fungi, and earthworms in the soil. Earthworms feed on the decomposing organic material and highly fertile, nutrient dense worm castings.
Worm castings are a digested, highly concentrated bundle of nutrients that your roses will love as they are in a form that is easier for the roots to absorb.
If you have access to well-rotted horse manure that is crumbly in texture and no longer smells then you can apply it as mulch around your roses in the spring.
However, if the manure still smells then it is a great idea to put it into your compost pile. The energy and microbes in the manure help to heat up the pile and increase the rate of decomposition so you can use your compost sooner.
If you add brown material to your compost (such as dried leaves, cardboard, and shredded paper) quickly stops the unpleasant smell of manure from spreading!
You must wait for horse manure to rot down into a decomposed form as fresh manure can burn the roots of roses and other plants during the decomposition process.
When to Apply Mulch to Roses
For optimal success, I recommend applying mulch at least twice per year.
- The first application should be at the start of the growing season in spring. This will allow the mulch to break down and release nutrients into the soil all through the growing season. A layer of mulch also helps to keep the roots of the rose nice and cool, helps the soil retain water, and improves structure for better drainage as well as suppressing weed growth.
- The second application should be done before the start of winter around the end of September. This will help insulate the roots from the most severe cold so that they can repair damage over winter and it gives your rose a head start in the following spring.
If it is a particularly hot summer I apply another layer of mulch as organic matter has a much higher capacity to absorb water than most soils do, so that the roots can draw upon this moisture when they need to, to prevent drought and keep the roots cool.
Mulch can also be added to the ground anytime to disguise the smell of other organic fertilizers such as fish emulsion and bone meal.
How to Apply Mulch to Rose Beds
Apply a 2-inch layer of mulch around your rose bed. There is no need to dig it in as this will disturb the soil’s ecosystem and you could potentially cut through rose roots with your spade.
Simply spread over the surface around the base of the plant and allow the worms and rain to integrate the mulch into your soil naturally.
Make sure that you leave about 5-6 inches of bare ground between the layer of mulch and your rose canes that emerge out of the soil. The wood of roses that is naturally above ground does not tolerate persistent exposure to moist organic material as this can lead to rot.
2. Alfalfa for Fertilizing Roses
Alfalfa is a popular natural fertilizer that has long been a favorite of organic gardeners and it’s usually the main ingredient in premade organic fertilizer mixes.
Alfalfa contains good amounts of nitrogen, magnesium, phosphorus, iron, calcium, and zinc all of which promote and support healthy growth for rose bushes and abundant flower production.
I personally use alfalfa in pellet form as it decomposes over time, gradually releasing the nutrients into the soil to benefit the rose throughout the growing season, whereas with some chemical fertilizers the water soluble nutrients can get washed away after watering or heavy rain, so there is less time for the roots to take in the nutrients and the product is essentially wasted.
Alfalfa is also valued for containing a growth stimulant called triacontanol which increases the number of basal breaks on rose bushes. Basal breaks are held in high esteem by rose growers they allow new canes to emerge which produce more flowers and over time replace older, spent canes when you come to prune your roses.
How and When to Apply Alfalfa For Roses
Alfalfa can be applied once a month in the growing season from the start of spring until the middle of August in order to allow any new growth to harden up before the winter dormancy.
I personally apply alfalfa pellets to the ground in April/May (when the leaves of the rose are unfolding) before applying mulch to the area surrounding the base of my rose bush and giving it a good long watering in with the soaker hose (or 4 gallons with a watering can).
When applying the pellets of alfalfa the next month, I simply rake the mulch to one side and scatter a handful of pellets onto the soil, and reapply the mulch with the rake, to encourage decomposition so that the nutrients reach the roots.
There is no need to dig it into the soil as they decompose and the nutrients find their way to the roots when you water your roses. Not only is digging unnecessary, but you are also lightly to damage the rose’s roots with the spade.
3. Epsom Salts for Roses
If you notice the foliage of your roses is turning yellow despite a good weekly watering regimen then the soil may be low in magnesium.
A magnesium deficiency in the soil can be a result of soil erosion or the fact that magnesium is sometimes not readily available in the acidic soils that are preferred by rose bushes.
Epsom salts contain high amounts of magnesium and are credited with greening up foliage, growing stronger canes, and producing more flowers.
Application of Epsom Salts for Roses
Applying Epsom salts couldn’t be easier. All your rose bush will need is half a cup each year applied in the spring when the weather is warming up. Simply mix your half cup into a 2-gallon watering can and water it around the base of the rose.
However, if your garden soil has a high salinity then you should skip this fertilizer completely. Gardens with heavily compacted soil (such as clay) that have poor drainage can accumulate salt in the soil which can stunt plant growth.
If you have well-draining soil with plenty of organic matter then this is unlikely to be a problem.
4. Blood and Bone Meal for Fertilizing Roses
Blood and Bone meal is a by-product of slaughterhouses that comes in a powdered form. It contains a good concentration of nitrogen to green up the foliage and promote new growth and Iron which is essential for photosynthesis and helps the leaves to produce chlorophyll.
It is also particularly good fuel for the ecology of the soil, which in turn breaks down organic matter and increases the nutrient availability in the soil so your roses grow stronger, produce more flowers, and are more resistant to disease.
Obviously, this is one to avoid if you are against the use of animal products. If you diligently use other plant-based fertilizers (such as alfalfa, manure, and coffee grounds) then skipping bone meal and fish emulsion shouldn’t be a problem as there are plant-based options that contain similar levels of nitrogen.
Application of Blood and Bone Meal for Roses
The smell of bone meal can be irresistible to cats, dogs, and potentially other animals that frequent your garden so you have to be careful in your application.
The best way is to rake back any soil or mulch surrounding the rose bush and apply the bone meal directly to the ground then reapply the soil and mulch over the top, you need to give it a particularly good long slow soak, preferably with a soaker hose as it will need several watering cans worth of water.
The combination of the slow watering and the mulch really helps to minimize any smells thus its attraction for wildlife and encourages the bone meal to infiltrate into the soil and reach the roots.
Bone meal will also help to improve the soil structure for better drainage and to ease soil compaction.
You can apply bone meal in the spring from March once a month but you should not add any more to the soil after August 15th as the plant needs to direct its resources to preparing for winter rather than stimulating new growth.
5. Fish Emulsion For Fertilizing Roses
Fish emulsion is a great tool in your organic fertilizing arsenal. This is because fish emulsion has a 5% concentration of nitrogen which directly feeds the plant to promote new, healthy growth in the spring.
This is an essential nutrient that all plants need to build chlorophyll in the leaves and stimulate the process of photosynthesis. It also contains potassium and phosphate for disease resistance and increased flower production.
It also is a tonic for the soil as it stimulates the activity of microbes in the soil which help break down organic matter and release their nutrients into the soil to benefit the rose bush.
Applying fish emulsion once per month in the spring helps to increase health and disease resistance later in the season.
The benefit of Fish emulsion compared to the other fertilizers is that it will reach the roots quickly. This is why it is so good when used in conjunction with slow-release fertilizers such as alfalfa to deliver a broad spectrum of nutrients over the course of the growing season.
How and When to Apply Fish Emulsion for Roses
The drawback of fish emulsion is the strong unpleasant, odor it exudes and the wildlife it attracts. Flies, cats, and dogs are all intrigued by this smell so you have to take some precautions when applying it.
You should always follow the instructions on the label, but the most common advice is to dilute one tablespoon of fish emulsion to one gallon of water in your watering can.
Application is as easy as just watering it in around the base of your rose.
But before you water in, as with all smelly, fertilizers the best way is to rake back any mulch you have laid down surrounding the rose to one side and apply the emulsion, and then rake the mulch back into place.
This does a good job of absorbing the smell and should hopefully discourage any inquisitive wildlife.
I personally use fish emulsion that can be diluted into water rather than the powdered fish meal as the emulsion drains into the soil to reach the roots and therefore the smell is far less potent than fish meal which can take a while to break down and for the smell to dissipate.
As with all the fertilizers that contain nitrogen, use this product once a month in the spring (from April/May) and make your last application before August 15th to prevent stimulating new growth just before winter.
Banana Peels For Fertilizing Roses
This appealing fertilizer (sorry I had to!) is one of my favorites when planting a rose bush because of its simplicity.
As unsophisticated as it sounds you can just throw a banana peel into the hole you have dug for your rose and plant the rose on top.
This will give your new (or transplanted) rose a welcome boost of potassium in the soil which encourages bigger, more spectacular blooms.
The sugars in the peel will also fuel the microbes and simulate worm activity, which will help to create channels for the roots of your rose and increase drainage.
If you are not planting a rose then you can simply throw banana peels into your compost and when it has rotted down you can apply it as a composted potassium rich supplement around the base of your rose at the start of spring.
As you can see that are plenty of options for fertilizing your roses organically that, when combined supply all the nutrients and minerals that your rose bush needs to grow successfully and produce beautiful blooms.
My preferred fertilizing regime is to apply either alfalfa, fish emulsion, or some bone meal once every 4-6 weeks during the growing season.
Roses are quite hardy plants however they are heavy feeders so even though three different fertilizers may seem excessive, your roses will reward you with a fantastic display. By rotating three fertilizers you are ensuring that the rose and the soil ecology have a ‘balanced diet’ and your rose will get all the nutrients it needs to thrive.
You also do not need to use any great quality of each fertilizer when you apply and one product should last you several seasons, so long term it is cost effective.
Also, there is of course the added benefit of not using chemical fertilizers which are ineffective at stimulating the ecology of the soil and can be to the detriment of the environment by causing excessive algae blooms in water courses which then die and deprive the water of oxygen and subsequently have a negative impact on the natural flora and fauna.
If you would like to read in more detail about the effects of chemical fertilizers take a look here, and why they are so detrimental to the environment and long term soil health, take a look at this article.
Rotate fertilizers as they contain different concentrations of nutrients and minerals