One of my gardening friends, who’s been growing peonies for decades, once gave the perfect answer when asked if she loved or hated them: “Yes.” If you’ve ever grown peonies yourself, you probably get it.
It’s impossible not to fall in love with those massive, ruffled blooms. But they can be frustrating, too—especially when they don’t bloom or suddenly come down with a case of leaf spot or rust.
The good news? With the right fertilizing strategy, you can give your peonies the boost they need to bloom beautifully—and stay healthier throughout the season.
Let’s dig into everything you need to know to fertilize your peonies like a pro.
When Should You Fertilize Peonies?
Before we talk about when you should fertilize your peonies, let’s cover when you shouldn’t.
Don’t rush it!
Some experts—like those at the North Carolina Cooperative Extension—recommend waiting until your peony has been in the ground for at least five years before fertilizing.
Others say you can start fertilizing lightly in the plant’s third year, once it’s more established. Here’s why:
- Year 1: Your peony is focused on settling in. If it blooms, pinch off the buds (yes, it’s hard!) so the plant can channel energy into roots and leaves.
- Year 2: You might see a few scattered blooms.
- Year 3: The plant’s roots are stronger, and you can begin light fertilization.
Key Times to Fertilize:
Once your plant is mature and ready for regular feeding, there are two ideal windows:
- Early Spring (when stems are about a foot tall)
- Late Summer to Early Fall (after blooming is done)
In spring, your peonies are using energy to grow stems and prep for blooms—like teenagers during a growth spurt. Later in the year, they store nutrients to support next season’s growth.
What Kind of Fertilizer Is Best for Peonies?
Peonies aren’t picky eaters, but they do have preferences. Here’s how to give them what they love:
1. Organic Compost
- Add a light layer around the plant’s drip line in early spring.
- Avoid piling compost directly on the crown or stems.
- Use your own compost or a store-bought, nitrogen-free blend.
Tip: Compost improves soil texture and adds nutrients slowly over time.
2. Slow-Release Organic Fertilizer
These fertilizers feed your plant gradually—perfect for long bloom periods.
- Apply about a month before blooming begins.
- Use gloves and a hand rake to gently work it into the soil around the drip line.
- Follow the packaging instructions based on plant size, climate, and rainfall.
Look for: A fertilizer with a low nitrogen content and higher phosphorus, such as a 4-10-10 mix.
What Do Those Fertilizer Numbers Mean?
You’ll see three numbers on fertilizer packaging: N-P-K (Nitrogen-Phosphorus-Potassium).
- N (Nitrogen): Too much = leafy growth, fewer flowers.
- P (Phosphorus): Helps with strong roots and more blooms.
- K (Potassium): Supports overall plant health.
Stick to lower-nitrogen blends like 5-10-10 or 4-10-10. Peonies don’t need a nitrogen overload.
Can You Use Manure?
You can—but proceed with caution.
While some gardeners swear by cow manure, the American Peony Society recommends against it. That’s because manure, especially when fresh or placed too close to stems, can lead to botrytis blight—a nasty gray mold that ruins stems and flowers.
If you want to go this route, make sure it’s well-aged composted manure, and never apply it directly to the crown.
Should You Use Water-Soluble Fertilizer?
Probably not.
Quick-release, synthetic fertilizers (often applied with a watering can) may burn your peony’s foliage, especially during hot weather or drought.
Since peonies grow just one set of leaves per year, it’s important to protect them as long as possible. Skip the fast-acting stuff and go with slow, steady nourishment.
What About Bone Meal?
Bone meal is great for building strong roots—but timing matters.
- Best time to apply? In fall or early spring before foliage appears.
- Don’t use it mid-season—it won’t help with blooming and may go to waste.
Fertilizing Tips You Don’t Want to Skip
Here are a few quick tricks that can make a big difference:
- Remove winter mulch before fertilizing.
- Apply fertilizer at the drip line, not on the crown or close to stems.
- Work it into the soil to prevent runoff and speed up nutrient absorption.
- Add mulch after feeding to help keep moisture in and temperature stable.
- Use a small kitchen measuring cup (designated for the garden) to apply consistent amounts.
Avoid Root Disturbance
Peonies don’t like having their roots messed with, especially in spring. If you’re dividing or transplanting, wait until fall—and don’t fertilize new transplants directly. Instead, prep the hole with compost first.
If Your Peonies Aren’t Blooming…
Resist the urge to dump more fertilizer on them. It might not be a feeding issue.
Check these common causes first:
- Planted too deep (peony buds should be just 1–2 inches below the soil).
- Too young (most peonies take a few years to hit their stride).
- Not enough sun (they need 6–8 hours a day to bloom well).
Final Thoughts
Fertilizing peonies doesn’t have to be complicated—but it does take some planning. Feed them at the right time, in the right way, and they’ll reward you with stunning, full blooms year after year.
Just remember: when it comes to fertilizer, less is more. It’s better to feed lightly than to overdo it.
Ready to See Your Peonies Thrive?
Try these fertilizing tips this season and see the difference for yourself! Share your results with fellow gardeners, or tag your blooming beauties online. Want more garden tips like this? Subscribe to our newsletter and never miss a planting guide again!
Happy growing! 🌸
