6 Best Fertilizers for Peonies | How and When to Use

Colorful, beautiful, and reminiscent of roses, peonies possess magic that’s all their own. And the fact that they’re not only long-lived but low maintenance makes them a firm favorite. 

But like every other plant, they thrive best when showered with love, care, and attention. Which starts with the right kind of nourishment. 

In this article, you’ll discover my favorite and best fertilizers for Peonies that I have unearthed through trial and error and the support and wisdom of some fellow expert gardening enthusiasts. 

You’ll also find additional pointers for making your peonies thrive, to enable them to fill your garden and home with fragrance for many happy years.

Best Peony Fertilizers

In any selection, there are always products that stand out among the rest, the cream of the crop, if you will.

In this case, for me, it’s these three. However Down To Earth stands alone for me personally, as I love their ethical standpoint, as well as their exceptional quality fertilizer ingredients. Whether you need an organic product or a convenient water-soluble product, all of these peony fertilizers will see you blooming all summer.

Choosing Peony Fertilizer

The best N-P-K fertilizer for peonies is typically a high potassium fertilizer to suit strong flower development such as a 5-10-5 ratio. Or you can apply a balanced 10-10-10 fertilizer if that’s what you have to hand. This ratio ensures that your plants get the proper amounts of nitrogen, phosphorus, and potassium. Nitrogen promotes foliage growth while phosphorus and potassium encourage healthy vibrant flower production.

If your peonies are struggling to flourish, it’s beneficial to add additional supplements, such as iron and zinc. Iron helps prevent chlorosis or the yellowing of leaves due to an iron deficiency. Zinc is important for overall plant health, but not as essential as nitrogen, phosphorus, and potassium. Compost or manure can also be applied to the soil for added nutrition.

It’s also important to apply a slow-release fertilizer that will continue to release nutrients and feed the plant over time. This can be achieved by using a granular top dressing, as opposed to a liquid feed.

Understanding N-P-K Ratio

As is the case with every other plant under your care, the ratio of nitrogen, phosphorus, and potassium in the fertilizer you will use for your peonies counts: this value is represented by the NPK ratio of the product.

Fertilizers that contain nitrogen (N), phosphorus (P), and potassium (K) are referred to as N-P-K fertilizers. Each macronutrient has its own distinct benefits, but they all serve the same purpose of aiding in plant growth.

Nitrogen is an essential macronutrient for plants as it helps with photosynthesis and encourages foliage growth.

Phosphorus helps to strengthen root systems and encourage blooming; it is also necessary for energy storage, protein production, seed development, and respiration.

Potassium aids in overall plant health by regulating water uptake from the soil and transporting essential minerals throughout the plant’s cells.

A balanced mix of these three essential macronutrients is necessary for successful plant growth, depending on climate, soil type, and the specific needs of the plants being grown.

In this case, when fertilizing peonies, phosphorus should be the highest nutrient ratio, while the values for nitrogen and potassium ideally should be lower. Products that have high nitrogen content should be avoided since they will encourage your peonies to produce a great deal of foliage at the expense of flowers.

Certain brands provide products that skip the potassium entirely while others will also provide it in low quantities.

Phosphorus and Calcium

Phosphorus is an essential nutrient that encourages vigorous growth in plants.  It is not only present in their DNA or genetic code, but also in ribonucleic acid or RNA which is responsible for interpreting it.

This macronutrient is also used in synthesizing plants’ energy storage molecule ATP and encouraging the development of quality blooms and fruit, healthy root growth, and resistance to disease.

Calcium happens to be a micronutrient, i.e., a nutrient that is required by plants in smaller quantities.

This mineral will help improve the structure of your peonies, enable them to make use of nitrogen efficiently and improve their root and leaf development.

Soil pH and Nutrient Uptake

Like roses, peonies prefer slightly acidic soil to neutral soil. For peonies, a pH of 6.5 -7.0 will work best.

At a lower pH, i.e., higher acidity, they may be incapable of absorbing the nitrogen, phosphorus, and potassium they need to flourish and develop strength in roots, stems, and foliage.

At a higher pH, i.e., lower alkalinity, they will be incapable of absorbing phosphorus, the all-important macronutrient for enabling them to bloom, iron which is important for chlorophyll production, and manganese which influences resistance to disease, drought, and stress.

Granular Vs Liquid Fertilizer

The main forms in which manufacturers provide fertilizers are liquid (available in concentrate or spray form) or granules. It is also possible to purchase spikes which are normally slow-acting and extremely convenient.

Liquid Concentrate or Spray

Rather popular and convenient to apply, liquid fertilizers – whether organic or non-organic – are often available as a concentrate that must be diluted before use. Offering a fast-acting burst of nutrients, these products contain a uniform concentration of the product, resulting in an even distribution.

That said they are often required to be applied on a more frequent basis compared to granular fertilizers. This can result in runoff as they leach through the soil.

Fertilizer Granules

Provided in the form of pellets, fertilizer granules – just like liquid feeds – can be either synthetic or organic.

They offer a slow release of nutrients and often need to be applied around the dripline of a plant and must be mixed thoroughly into the soil and watered thoroughly to become activated and start benefitting plants and soil.

Fertilizer granules can be distributed using a spreader for even results although you can easily apply them manually with your hands when broadcasting over a smaller area. (You will need to wear heavy-duty gloves for protection.)

They generally keep well over extended periods of time and are easy to store.

Fertilizer Spikes

Another slow-release option and extremely convenient, fertilizer spikes present the option of feeding your plants gradually over several months without having to constantly provide top-ups.

Most manufacturers will tell you to insert them around the dripline of the shrub.

They may be either organic or synthetic and come with a reduced risk of runoff.

That said they tend to be more expensive compared to the more commonly used options mentioned above.

Organic vs Synthetic Fertilizers

In addition to their consistency, fertilizers can also be classified according to the nature of their constituent ingredients.

Organic fertilizers

Products in this category contain natural ingredients such as bonemeal, feather meal, kelp, and beneficial organisms such as mycorrhizal and archaea.

They are generally slow acting and are eco-friendlier when compared to synthetic, chemical-laden alternatives. They also mean a reduced risk of overfeeding and runoff and can also improve the conditions of the soil.

Because they are natural, they do not result in the accumulation of any harmful salts over time, which can lead to fertilizer burn.

Synthetic fertilizers

Products in this category are manufactured using chemical sources of nitrogen, phosphorus, and potassium, as well as other macro and micronutrients.

Synthetic fertilizers are usually more potent compared to their organic counterparts and as a result, come with a risk of overfeeding and runoff. They also tend to act faster compared to the latter.

Peony Fertilizers Reviewed

Having used all of these products, and a few others that did not make the shortlist…, I can say with confidence that all of the products below work very well. I have ranked them based on a number of factors, including overall performance in producing good blooming peonies, value for money, and ease of use. I have also given consideration to their environmental impact too.

I have supplemented my own experience and thoughts with a lot of customer research from major online retailers and taken their user feedback into consideration too. Just so my opinion remains balanced with a broader set of feedback.

Pros

• Environmentally friendly and suitable for organic gardening
• Ideal for flowering and fruiting plants
• Free of low-quality additives

Cons

• Packaging may need securing to avoid leakage

The best products come from manufacturers who care. And this brand cares, not just about helping you get closer to nature, but helping you save the environment as well.

This means you can look forward to the very best nutrients for your peonies to blossom beautifully without any poor-quality additives.

This slow-release feed also contains calcium ensuring your plants will look picture-perfect with straight stems and firm branches. And there’s just the right amount of nitrogen to add a verdant touch too.

You too can get to enjoy its perks thanks to its high phosphorus content which is just what your peonies need to fill your garden with color and an abundance of blooms.

A self-confessed fertilizer buff, I can attest to having witnessed its effects first-hand not only on my peonies, but also when used as a fertilizer for pumpkins, tomatoes, and lilies too.

How to Use

If you’re planting your garden from scratch, you will need to apply 2½ – 5 pounds of the product to the top 3 inches of the soil (for every 100 square feet). Care should be taken to blend it in properly.

If you happen to be using pots simply add 1-2 tablespoons per gallon. Once your floral charge starts to produce new growth, provide the same amount monthly during the growing season.

Pros

• Specially manufactured for floral and fruiting plants
• Capable of providing prompt results

Cons

• Risk of overfeeding if manufacturer’s guidelines are not adhered to

Fast-acting and water-soluble, this fertilizer from the Miracle-Gro range is every gardener’s dream especially if your charges tend to be floral or fruiting plants.

The proof is in its impressive phosphorus content ensuring your peonies and other flowering perennials will have the boost they need to unleash their splendor in spring and through to summer.

Thanks to its nitrogen and potassium content, I tend to use this feed when my flowering or herbaceous perennials are looking a little lackluster from soil depletion or a particularly harsh winter. An application of this in early spring really helps to get flower production and foliage growth moving.

It’s hardly any surprise since this is one brand that comes with the promise of quality and awesome results making this product one that is worthy of your peonies in every way.

How to Use

For outdoor plants simply add 1½ tablespoons per 1½ gallons of water and feed every 7-14 days.

Change the quantity of fertilizer to ½ teaspoon for your indoor peonies and apply every 14 days.

Pros

• Mycorrhizal fungi form an improved root system
• Archaea for an effective breakdown of soil substances
• Reduced risk of runoff
• It May be used around kids and pets

Cons

• It May give off a pungent odor before use

Organic fertilizers aren’t usually known for their speed, but here’s one product capable of acting faster than most.

The key success in these flower fertilizer spikes from Jobe’s is the presence of archaea. This can break down nutrients in the soil more efficiently so that your peonies can absorb them more easily and therefore make use of them quickly.

And while these convenient slow-release spikes are taking care of your flowers with a potent blend of friendly microorganisms, they will also take care of your soil too, ensuring an optimum growing environment for your plants.

The icing on the cake is Jobe’s Organics certification from the Organic Materials Review Institute (OMRI), making it just right for eco-friendly gardening and growing robust plants that are equipped to stave off pests and diseases.

How to Use

Using a plastic cap and a hammer, punch spikes 1 or 2 inches into the soil (ensure they are 10 – 12 inches from the stem of your plant).

The number you’ll need will depend on the diameter of each shrub: 4 spikes for 2 feet, 6 for 3 – 4 feet, and 8 for 5 – 6.

Pros

• Ideal for flowering and fruiting plants
• Suitable for indoor and outdoor plants
• Suitable for frequent feeding

Cons

• It May cause burning if overused

Any product which comes recommended by the farming industry and floristry guilds is one worth giving a try. Which is the reason why most people (including myself) have reached for Jacks’s Classic Blossom Booster. And not only for peonies. This feed can be used for indoor plants such as amaryllis and outdoor flower beds of carnations, roses, and lilies. 

But why does this water-soluble fertilizer work so well? The first hint is that rather large number in the middle: Phosphorus always means good news when it comes to getting those flowers to bloom.

The second is its potassium content which will enable your plant to use water more efficiently while looking healthy and sprightly. And the third is nitrogen which will enable it to get the energy it needs to ensure the first two processes work like a dream.

It also earns points for being suitable for frequent feeding (do ensure you adhere to the manufacturer’s instructions), and for the handy measuring spoon and instructions to ensure you feed your peonies right.

How to Use

Add 1 tablespoon to a gallon of water for outdoor plants and ½ a teaspoon to the same quantity of water for indoor plants (water every other week in the latter case). 

Pros

• Slow-release nutrients including bonemeal, calcium, magnesium, and zinc
• Improves soil quality
• Suitable for organic gardening 

Cons

• An organic odor that may be attractive to pets

No fillers or sludge. Just organic, fast-acting goodness. That’s what the family-owned brand that is Espoma promises. And with almost a century of experience in the gardening industry under their belt and four generations of expertise, there’s no doubt that they must be doing something right. 

The presence of bonemeal in this product means your peonies will get to benefit from calcium and phosphorus for excellent structure and large, colorful blooms.

Bonemeal also contains zinc and magnesium as well; their presence will ensure your peonies are able to form chlorophyll (all the better to trap sunlight with which to create energy), and use that essential ingredient, phosphorus, effectively.

It also releases its nutrients slowly ensuring your peonies will receive nourishment over time and will also improve the quality of your soil making it as close to the perfect fertilizer for your peonies as can be.

How to Use

For outdoor plants mix 10lbs per 100 square feet into the soil and for potted plants sprinkle 1 heaped tablespoon onto the soil. Blend well into the soil and water thoroughly. For shrubs: Apply 1 or 2lbs depending on the size of the plants

Pros

• Free from low-quality additives and OMRI-certified for organic gardening 
• Helps strengthen root growth, especially in new plantings
• Ideal for floral shrubs 

Cons

• It May cause plant burn if used excessively

Brought to you by a manufacturer which prides itself on its dedication to integrity, this OMRI-certified product from Dr Earth is completely natural and therefore suitable for organic gardening.

It’s also free of troublesome ingredients including sewage sludge and chicken manure.

Only high-quality ingredients including fishbone meal, kelp meal, and feather meal are present.

Thanks to them your peonies will be able to enjoy phosphorus, nitrogen, and calcium in appropriate amounts to produce bright splashes of color amid rich greenery. They will also benefit from a robust root system.

All of which will contribute to making your flowers appear worthy of a spread in your favorite lifestyle magazine.

How to Use

For new tubers planted outdoors: Add 1 cup per ½ cubic foot of the soil which will be used to close up the hole. Once it has been closed up, mix in another cup and water properly (to dissolve it and to also prevent your resident canine from attempting to ingest it). Remember to plant your bulb no deeper than 2 inches below the soil unless it will not bloom.

The new plant will have to be fed every 8 weeks during the growing season.

For established plants: Add 2 cups per diameter inch of shrub and water properly — measurements will have to be taken about 4 – 6 inches above the soil surface. Repeat for every other month during the growing season.

For potted plant tubers: Add ½ cup per ½ cubic foot of soil and water properly.

For established potted plants: Use 1 tablespoon per 6 inches and 4 tablespoons per 12 inches of your container. Mix in thoroughly, cover with ½ – 1 inch of mulch, and water properly.

You might also enjoy reading Companion Plants for Peonies | All-Season Color

How to Fertilize

Providing your peonies with the nourishment they need is a pretty straightforward affair: it is simply a question of applying the right fertilizer at the right time and in the required amounts.

To give your peonies a head start, add a slow-release fertilizer to the soil in the late fall and again in the early spring about 4 weeks before the growing season kicks off. The product should be applied to the soil around the plant’s dripline ensuring you adhere to the manufacturer’s instructions.

It should also be mixed in thoroughly and watered. Bone meal fertilizers or those for roses will work best for these flowering plants.

Avoiding Fertilizer Burn

Fertilizer burn occurs when excessive quantities of a product are applied to a plant. As a result of the increased concentration of mineral salts, moisture is drawn out from the seedling, shrub, or tree.

Symptoms of the issue include the presence of brown or yellow patches or spots on leaves owing to the reduced quantities of water available to the plant and a possibly compromised root system.

Preventative Measures

How can you ensure your peony never experiences fertilizer burn?

• By following the manufacturer’s instructions: Always adhere to the measurements and methods specified by the manufacturer on the product packaging. Doing so will ensure you are able to avoid providing more fertilizer than your plant requires, placing it at risk of fertilizer burn as a result.
• Avoid adding fertilizer to wet soil:  Fertilizing dry soil and then applying water can help to minimize the risk of fertilizer burn.
• By applying organic fertilizer: Products in this category are usually milder compared to their chemical-based counterparts.
• By opting for slow-release options: Fertilizers in this category release their goodness gradually over time and as a result, are less likely to cause the prompt accumulation of salts in the soil.

When to Fertilize

Peonies should be fertilized in late fall and early spring. Feeding them in autumn will see them ready for the rigors of winter. 

Fertilizing in Spring, just before bud set will ensure they have the nourishment they need to thrive throughout the growing season. 

Only fertilize in late spring (after bud set) and in the summer if your peony isn’t flourishing as it normally does. A lack of flowers, leaf drops,s or poor growth could be a result of poor soil conditions or due to common plant stressors such as freezing winter temperatures, summer drought, or disease or pest infestations.

How Often to Fertilize

Peonies are not heavy feeders and providing they are planted in nutrient-rich soil that has been composted and regularly mulched, they may only need to be fertilized once a year around spring. 

However, it is also possible to feed them twice a year as well, by applying an initial dose of fertilizer during the fall. Ultimately the frequency with which you will apply fertilizer to your plant will depend on the product you happen to be using and the manufacturer’s instructions.

Verdict: Best Fertilizers for Peonies

When growing peonies most of us have one primary quest and that is to make our peonies the envy of the neighborhood.

For me, the best organic slow-release fertilizer is Down to Earth Organic Bone Meal Fertilizer. It is an excellent choice for feeding your peonies because it is high in phosphorus and low in nitrogen which is essential for ensuring healthy blooms and foliage. 

When your peonies need a little ‘pick-me-up’ and seem to be lacking in vibrancy or blooms, then you’ll need a Miracle-Gro bloom booster. It’s a liquid feed that gets straight to the roots in no time.

If convenience is what you are looking for then I recommend you choose Jobe’s Organics Fertilizer Spikes. Not only great for your peonies for slow-release and long-lasting results but also great for other bloomers in your garden such as roses. 

FAQ’s Fertilizing Peonies

Do Peonies like Epsom salts?

Yes, they do. Epsom salts can help plants absorb nutrients more efficiently without building up in the soil. Add one tablespoon to a gallon of water and mix it with the fertilizer you have just applied. 
They can be absorbed by your skin hence gloves should be worn before applying them.