How to Fertilize Peonies (and the Best Fertilizer to Use)

Peonies are pretty low maintenance flowers, but sometimes they need a little bit of a boost to produce at maximum capacity. With the proper care, one peony plant can give you dozens of beautiful flowers each year. They’re prized by pollinators, make excellent cut flower displays, and even help to keep deer away from the rest of your garden. If you want to know how to maximize your peony harvest and grow even more stunning flowers, this guide to how to fertilize peonies is for you!

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First, Do Peonies Need Fertilizer?

Peonies are tough plants that don’t need a lot of babying in order to come back year after year. I’ve been growing peonies for almost two decades now, and I can say that once they’re established, they are vigorous plants with incredible flower production (depending on the variety, one plant can give you up to 50 blooms per year if it’s happy and healthy!). Plus, they can keep yielding gorgeous flowers for many years as long as they have the nutrients they need.

Whether or not your peonies need fertilizer depends on your individual soil and how your plants are doing. Just because you have flowering plants each season doesn’t necessarily mean that your peony flowers couldn’t benefit from more fertile soil. Providing your peonies with the right nutrients can significantly improve the display of these breathtaking flowers in your garden.

How to tell whether your peonies need fertilizer

So how do you know whether your peonies need fertilizer or not? One of the best ways to find out is to take a soil test. This is probably the easiest and best way to see whether you have too much or too little of any specific nutrient that your peony plant needs to grow. 

Peonies need a balanced NPK ratio – in other words, a healthy mix of nitrogen (N), phosphorus (P), and potassium (K). If you have too much or too little of any one of these elements, you’ll see a significant difference by adding some fertilizer to your soil. 

Here are some other ways to tell whether your peony flowers are hungry:

• Weak blooms. Too much nitrogen can cause plants to put all their energy into growing leaves and stems rather than flowers. If your flowers seem unhappy or if you only have a few flowers with significant foliage growth, you probably have a nitrogen imbalance. 
• Droopy stems. On the contrary, if your flowers are too big for their stems and the stems seem saggy or unable to hold up the weight, they’re probably lacking in nutrients. In this case, a balanced fertilizer can make a big difference.
• Fewer buds. Peony bushes can produce an incredible number of blooms each season. While different types of peonies have different production rates, most plants can produce 30-50 blooms per year once they’re established. Keep in mind that it takes a few years (typically 2-5) to establish mature plants. If your plants are mature and only producing a few flowers per year, they probably need some fertilizer! 
• Diseases. If your peonies seem disease prone, it may also be a sign that your soil is lacking in essential nutrients. (However, peony diseases can also be the result of overwatering and lack of air circulation. Here’s a helpful table for troubleshooting peony diseases.)

What Nutrients Do Peonies Need?

For ideal growth and production, peony plants need a balanced ratio of nutrients. They require a simple formula of three main elements:

• Nitrogen (N): Nitrogen promotes healthy foliage growth. However, too much nitrogen can lead to weak stems and few blooms.
• Phosphorus (P): Plants need enough phosphorus for growing thriving flowers as well as for strong root development. If your soil is low in phosphorus only, bone meal can be a good supplement to add for increasing this nutrient.
• Potassium (K): Potassium aids in larger blooms and stronger stems while also protecting plants from diseases. 

Peony plants will thrive with a mixture of equal amounts of nitrogen, phosphorus, and potassium (along with well-draining soil and regular watering, of course). In most cases, a balanced 10-10-10 fertilizer can do wonders for healthy plant growth. However, if you can, it’s a great idea to test your soil so that you can add a custom mixture of these nutrients as needed.

If you want to start with a simple organic option, you can go ahead and add some well-rotted manure, compost, or other organic material around your peony plants in order to boost your soil’s nutritional makeup.

When Should You Fertilize Peonies?

The early spring is the best time to fertilize your peonies for maximum effectiveness. You can add your fertilizer when you start to see your peonies sprout with new growth. Look for stems that are about 2-3″ tall.

Adding fertilizer around your young shoots in the springtime will help promote strong roots and give your plants the essential nutrients they need throughout the growing season.

If you’re just getting started with planting peonies, you might consider fertilizing both in the spring and in the fall for the first 2-3 years. Starting your plants off in nutrient-rich soil with plenty of compost will also help them take off more quickly. After they’re established, you can cut down to only fertilizing in the spring. In fact, for mature plants, you may only need to fertilize every couple of years.

Types of Fertilizer

If you’ve decided to give your peonies a boost, what type of fertilizer should you use for your plants? 

While some flowers can be quite particular when it comes to choosing the right fertilizer, peonies are fairly low maintenance and can do well with most balanced fertilizer options. 

Here are the main types you might consider using:

Liquid fertilizer 

Liquid fertilizer is easy to use and absorbs into the soil quickly, which generally produces quicker results in your plants. This is because the nutrients are already dissolved, so they’re ready to feed your plants right away! Liquid can also be easier to apply evenly. 

Granular fertilizer

Granular options are usually slow-release formulas, so they distribute the nutrients evenly over a longer period of time. Slow release fertilizer options sometimes require fewer applications, which can also make them more cost effective over time. 

(Since peonies generally just need one application per year, though, this isn’t really a big deal in this case.)

Organic fertilizer

Many gardeners prefer to put organic matter back into the soil. This is a good option for cost effectiveness and can also reduce the risk of over fertilizing. Good organic fertilizer options for peonies include composted manure, natural bone meal fertilizer, and other homemade compost.

How to Apply Fertilizer to Peonies

Once you see those shoots popping up, apply your fertilizer a few inches away from the stem around the drip line of the plant. Peonies are highly sensitive to fertilizer burn, so be careful to not let the fertilizer touch the plant. 

After you’ve spread your fertilizer on the soil surface around the base of the plant, work it in gently. Then, water thoroughly to help the nutrients penetrate into the soil. 

(Don’t forget to check your fertilizer package for any additional instructions!)

My Favorite Peony Fertilizer

My favorite option for peony fertilizer is True Organic Bloom Booster. You can buy it on Amazon or from most local garden centers or home improvement stores. 

This is a general-purpose fertilizer that comes in both liquid and granular form. I prefer the liquid because it’s easy to use and quick! 

Not only does this fertilizer produce great results for my flowers, but I also love that it’s safe for both people and dogs and is so easy to apply. 

Favorite Peony Varieties

If you’re shopping around for some more peonies to add to your garden, here are some of my favorite varieties that I’ve grown!

• Bridal Shower (all white)
• Gay Paree
• Kansas
• Sarah Bernhardt

More Peony Care Tips

Fertilization is just one aspect of peony care. Here are some other important tips for making sure your peonies are healthy and happy.

• When planting peonies, get them in the ground during the fall before the first frost arrives.
• Plant 2-4′ apart to provide good circulation.
• Don’t worry about ants. Your peonies need them for maximum blooming!
• Provide support for heavy plants (tomato cages, peony rings, and stakes work well.)
• Deadhead any spent blooms when the season is over.

Want to know more about growing peonies? I expanded on all of these tips in my blog post, Tips and Tricks for the Best Peonies. After almost 20 years of growing, these beautiful flowers are still right up there at the top of my list!

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xoxo,

Kelly