Peonies Have Finished Flowering? Here Are 7 Things You Should Do Right Now for for Bigger, Better Flowers Next Year

How sad is it when peonies stop blooming? It’s like they are telling us that spring is gone, and the hot season is coming – ok, “Not really bad news,” you may say… True, but still their romantic, English garden personality already has a melancholic feel to them. Soft and round, in delicate shades of white, pink, salmon, yellow and gold, and blushing to red, the flowers of this bushy perennial have that sense of “transience”, of time standing still while they are opening to the Sun, but also a sad aftertaste when they leave us.

It’s like leaving an old idyllic world behind, and, personally, it reminds me of when my summer holidays were over, and I left a passionate crush on the beach.

If you too, like me, have a soft spot for peonies and their blossoms, then you too will want your leafy beauties to be healthy till the end of the season, and, maybe with a pinch of selfishness, feel that thrill of seeing them shoot again next year, and look forward to more and more amazing blooms.

It’s like the generous 6 weeks that peonies’ blooms in our garden are never enough – we want more (though it’s actually quite a long flowering season).

And then, we all love peonies for their magical flower display, but their leaves, large, lush, deeply cut and rich green leaves keep our borders and gardens fresh through the summer – do you get the feeling that they want to embrace you, as I do?

But… You can’t forget your peonies just after they have blossomed; they still need your care, and they still run health risks till the end of the season.

So, do you want peonies to stay healthy and give you more flowers next year? Follow me in this romantic journey.

1: Deadhead Spent Blooms

Put yourself in the shoes of your peonies (I know, they don’t have them, but humor me…) Imagine how much energy they put into producing those big blooms. And what do they want to do next? They want to reproduce by seed.

The problem is that propagating peonies by seed is not a good idea; the “babies” often come out different, less showy and colorful than the parents. So, they are no use to you. Yet, your flowering queen is ready to invest even more energy producing them.

You will have to be cruel to be kind here, and deadhead all the spent blooms, even before they turn brownish.

The problem with peonies is that they have very strong stems, so you cannot just pinch the blooms.  So…

Get your pruners (or a grafting knife, I prefer it – it’s more precise), and disinfect them (apple cider vinegar or alcohol are fine). Then cut the stem just above the first set of healthy leaves with 5 leaflets (not less!). Don’t worry if you need to cut a longish bit; you want your peonies to keep only strong growth.

Disinfect the blades every single time you move to the next peony, otherwise, you risk spreading diseases from one to the other!

If you have some blooms that still look attractive, let them dry and take them home; they will remind you of the charming show your peonies gave you earlier in the season.

2: Feed Only If Necessary

I find that healthy, strong, well-established peonies usually need no fertilization after they bloom; however, you can still give them a bit of compost (a couple of cups).

However, sometimes they do need it, if you see that they are struggling. “And how do I know?” Good question. Look out for these signs:

• Fewer flowers than usual over two or three seasons.
• Weak stems and smaller leaves.
• Poor annual growth, with stems noticeably shorter than in previous years.
• The plant has been in the same spot for 5–10 years without any feeding.
• The soil is very sandy, where nutrients leach away quickly.

Or in case you regularly remove plant material without returning compost or organic matter to the soil.

In this case, use a low-nitrogen, slow-release (granular) fertilizer. You want your peony to keep healthy and focus on strengthening and growing roots, not leaves. And these beauties have no problems producing leaves! Choose any of these NPK ratios: 5-10-10, 5-10-5, 4-8-8 or 3-5-5.

A tip: if your peony only has minor problems, pick a low-nutrient fertilizer (NPK 3-5-5 or 4-8-8) or use half the dosage a medium one, like 5-10-5 or 5-10-10, which you should use instead for more serious symptoms.

The usual dosage is about ½ cup per plant for peonies (100 to 120 ml); but do check the instructions, because it may depend on the (did I write organic? It goes without saying…) fertilizer brand. Scatter the granules around the plant but away from the crown (base of the stems).

“Can I use just compost?” Yes, in most cases it works fine, especially if you notice that your peony is generally weak. 1 to maximum 2 inches (2.5 to 5.0 cm) will suffice.

You could also use some organic supplements, but be very careful. To be safe, pick one a stick to the dosage I give you as a maximum, less is more in this case:

• Bone meal, which is super rich in phosphorus, essential for root development (usual NPK 3-15-0). Use ¼ to ½ cup (60 to 120 ml) per adult peony, working it gently into the soil – only once.
• Fish bone meal, which is rich in phosphorus too (typical NPK 4-12-0); only ¼ cup (60 ml) worked gently into the soil once after your peony has bloomed.
• Wood ash, which is rich in phosphorus and potassium, but also trace nutrients, and these are essential for your peony’s health. Only use one or two tablespoons.

“I heard that Epsom salts are great for peonies, shall I use them?” Not at this stage, in this phase of your peony’s life cycle; only use them if you have a soil test which shows magnesium deficiency (in which case, 1 or 2 tablespoons in a gallon, 4 liters, of water, and once).

3: Clear Spent Petals and Debris Around the Base

I know, that carpet of fallen petals around the base of your bush looks incredibly romantic. It’s like a picturesque, pastel-colored snowstorm has swept through your summer garden. You might be tempted to leave it there to slowly fade into the earth—a melancholy reminder of the bloom party that just wrapped up.

Please, don’t. While it looks like a scene from an English fairy tale, that layer of floral debris is actually a ticking time bomb for your plant’s health.

As those large, soft petals decay, they act like a sponge. They trap moisture against the soil and severely restrict vital air circulation around the crown of your peony. Add a little summer humidity to the mix, and you have just created the ultimate luxury resort for fungal spores—particularly our absolute worst enemy, Botrytis paeoniae (Botrytis blight), which we talked about in Task 4.

To keep your peony breathing easily, you will want to gently rake or hand-pick all fallen petals, dead leaves, and snapped twigs right off the soil surface. Your goal is to respect the radius by clearing a completely bare, debris-free ring measuring 1 to 2 feet (30 to 60 cm) directly around the crown (the base where the stems meet the soil).

Once you have gathered it all up, make sure to bin it rather than compost it. Because peony debris is so highly susceptible to harboring microscopic fungal spores, do not throw these spent petals into your home compost bin unless you are absolutely certain your pile gets hot enough to kill pathogens. Play it safe and dispose of them in your municipal yard waste or regular trash.

4: Water Deeply, Regularly and NOT Too Often!

By now you know that your priority is to get your peonies to strengthen their roots once their blooms have finished lighting up your garden. And you can do it with proper, deep watering too.

If the water seeps deep into the soil, your peonies’ roots will follow it. Instead, if you irrigate often but little, moisture will stay at surface level, and so will roots. This is risky if you get a heatwave or a spell of drought, because humidity only remains lower down in the soil. So…

• Only water your peonies when the top 2 inches of soil are dry (5.0 cm).
• This is usually every 10 to 14 days, but it depends on your climate, soil etc. So be flexible.
• Give each peony 1 to 2.5 gallons of water (4.0 to 10 liters), depending on its size and temperature.
• Water them early in the morning or late in the evening with room temperature, dechlorinated water. Leave it out for at least 30 minutes before irrigating your peonies

Do make exceptions during heatwaves or drought, but as you can see, also watering peonies after they bloom is pretty straightforward.

5: Find and Treat Diseases and Pest Infestations

Now I’ll ask you to imagine being a little insect in search of food and shelter from predators. What would you do when you see all those dense, tender and lush leaves on a shrubby peony?  You guessed it!

You want your peonies to stay healthy till fall, actually till the foliage dies out (usually just after the first frost. They need the leaves to produce food through photosynthesis and they need healthy stems to move it (and water, minerals etc.) around.

But peonies are very “yummy” for molds and pests, so you will need to keep checking (look deep into the center of the plant; that’s where these trouble-makers tend to hide) and act swiftly!

But what are the most common diseases and pests of peonies after they bloom? I have written up a thorough list, with symptoms and what to do:

Botrytis blight (Botrytis paeoniae)

• Typical symptoms: Brown or black patches on leaves and stems, soft rotting shoots, fuzzy grey mold in damp weather, buds or stems collapsing.
• Treatment: Cut off and dispose of affected parts, improve air circulation, avoid overhead watering, remove all plant debris in autumn. Copper-based organic fungicides may help if applied early.

Powdery mildew (Erysiphe spp.)

• Typical symptoms: White, powdery coating on leaves, sometimes causing yellowing and premature leaf drop; usually appears in late summer.
• Treatment: Remove badly affected leaves, thin surrounding plants to improve airflow, avoid wetting foliage. Neem oil or sulphur-based organic sprays can help slow its spread.

Leaf blotch (red spot) (Cladosporium paeoniae, also known as Graphiopsis chlorocephala)

• Typical symptoms: Purplish-red to brown spots on leaves, often with darker margins; heavily infected leaves may yellow and drop early.
• Treatment: Remove infected foliage, clean up fallen leaves, water at soil level, improve spacing and air circulation. Copper fungicides may be used preventively.

Peony wilt (Phytophthora blight) (Phytophthora cactorum)

• Typical symptoms: Sudden wilting, blackened stems near the base, water-soaked lesions, collapse of shoots, root and crown rot.
• Treatment: Improve drainage, avoid waterlogged soils, remove severely affected plants and surrounding soil if necessary. There is no reliable organic cure once infection is advanced.

Root and crown rot (Fusarium spp. and other soil-borne fungi)

• Typical symptoms: Yellowing foliage, stunted growth, poor flowering, soft or decaying roots and crown tissue.
• Treatment: Lift and inspect affected plants, remove rotten sections if possible, replant in well-drained soil, avoid overwatering.

Peony ring spot (Peony ringspot virus)

• Typical symptoms: Yellow rings, mottled or distorted leaves, reduced vigor, occasional poor flowering.
• Treatment: There is no cure. Remove and destroy severely affected plants and avoid propagating from infected stock.

Southern blight (Sclerotium rolfsii)

• Typical symptoms: Sudden wilting, brown stem lesions near the soil line, white cottony fungal growth with small tan “mustard seed” structures.
• Treatment: Remove infected plants and debris promptly, avoid moving contaminated soil, improve sanitation and drainage.

As you can see, all the treatments I have given you are natural and cheap, no need to pack your soil with chemicals.

6: Leave the Foliage Alone!

This is a mistake to avoid rather than a task: cutting or thinning the foliage after your peony has bloomed. I think some amateur gardeners do it believing that these perennials are a bit like bulbs and tubers. No… They have a different vegetative cycle.

In fact, tubers bloom, then they usually keep the leaves for a few weeks and they go dormant (to sleep). Instead, peonies are early bloomers, but then they keep the foliage on for months.

So, only check that the leaves and stems are healthy, like in task 4, and don’t get the idea of thinning them.

Finally…

7: Be Patient and Leave Major Intervention for the End of Fall

Another mistake, linked to the one in task 5. Even as the foliage of your peonies starts looking “tired” later in the seasons, wait for it to die off before you prune them (actually, you have to cut them back, if they are herbaceous or transactional). First of all, though…

…Know your peony!

There are three types of peonies, and each requires a different end of season treatment:

• Herbaceous peonies (Paeonia lactiflora and hybrids): Cut back to 1–2 inches (2.5–5 cm) above the ground after the foliage has been killed by frost in late autumn.
• Intersectional (Itoh) peonies (Paeonia × itoh): Cut back to 4–6 inches (10–15 cm) above the ground, leaving the short woody stem bases intact because the dormant buds (“eyes”) may sit slightly above the crown.
• Tree peonies (Paeonia suffruticosa and hybrids): Do not cut to the ground. Only prune dead, damaged, or crossing branches, as the permanent woody stems produce future growth.

That’s All Folks!

For the beauty they add to your garden, and the many years of floral spectacles (they live very long, into their fifties), peonies require little and simple care. After they bloom you only have 6 things to do (or not do), and you can be sure that your romantic queen will be back with massive blooms again next spring.