Peonies - Care and Maintenance
Peonies Part 3 - Peony Care & Maintenance
Now that you’ve planted your peony, you’re set to get years of enjoyment out of it without a whole lot of care. Peonies are generally pretty hardy and planted in an ideal location, they will often thrive in spite of neglect. They are known to be deer resistant and unlike other perennials, peonies don’t need to be dug up and divided every few years. They do take time to develop and establish - some varieties take two to three years before they really take off to grow and bloom.
The first year after planting your root, it’s important to not let it dry out, especially in hot weather. Peonies form their new eyes for the next season during summer, so it’s important to keep them hydrated so they’ll make a strong show the following year.
Generally in our Zone 8 climate, spring and fall rains will do a great job of watering it. When the rains drop off is the time to ensure you step up and take over. For a new planting, a general rule of thumb is to give it a deep watering once a week. If your soil is loose and sandy, it may take more watering in hot weather. Established peonies on the other hand should only need a deep watering every two weeks. Be sure to water your peonies at the ground level, with a good soaking and avoid spraying or wetting the foliage, which could cause disease.
Since you amended your planting hole with plenty of good compost and some fertilizer, your peony will likely not need fertilizer for a couple of years. This is about the right cycle also to add some fertilizer to more established peony plantings. Be careful not to over-fertilize as this can reduce flowering and lead to plants that die prematurely.
Fertilizers with high levels of Nitrogen (N) should be avoided because they will cause excessive foliage and fewer blooms. Phosphorus (P) and potassium (K) are macronutrients that will help the peony maintain a strong root system and encourage blooming. Remember, fertilizers are rated in N-P-K. So any organic fertilizer that is lower in N and higher in P and K is best -- like a 5-10-10 or 5-10-5, will work. Bone meal is also a great fertilizer for peonies as it’s high in P, and adding some dolomitic lime to keep the soil sweet when you add fertilizer will also help.
Fertilizer should be applied in the Spring when shoots are 3-4” tall. Keep the fertilizer about 6” away from the crown and shoots of the plant to prevent burn and water it in and/or cover lightly with a light application of compost. This is more important if you use organic fertilizer and/or bone meal as these attract four legged animals who will lick your fertilizer up if you don’t water it in or cover it up. Synthetic fertilizers will also work, however it’s more likely they will burn your plant and are really not healthy to use in your soil long term.
If peonies have any weakness it’s in their stems, which sometimes struggle to support their gigantic blooms. Also, if your peony is exposed to heavy winds, it may need some support. Three legged metal rings or even tomato cages centered around the crown of the plant can help support a peony that needs it.
Cutting back and deadheading are two maintenance tasks that will keep your peonies healthy, strong and tidy looking. Deadheading is the process of removing spent blooms from your plant. A plant invests a lot of energy into reproducing itself first through blooming, then setting of seeds. Removing the blooms, whether to bring in to brighten your home or after blooming in your yard or garden, allows the plant to invest that energy into developing roots and buds for next year. I think it’s especially important to deadhead your peony in the first few years after you plant it to help it develop and grow strong. The best way to deadhead is to not just cut off the head of the bloom, especially since the blooms are often on stems taller than the plant’s foliage. Instead cut deeper by following the stem down to the second or third leaf on the stem and cutting there. This buries the cut end of the stem in the foliage and keeps your plant looking tidy and neat.
Cutting back happens in the fall, after frost has killed the peony foliage. Simply cut the stems down to ground level and remove them, along with any leaves or other debris and dispose of them in the trash, not your compost. Fungal diseases can survive on stems or leaves left over the winter, so removing them will help keep your plant healthy.
In our Zone 8 climate, it’s not really necessary to mulch plants to protect them over winter, so don’t bother. It’s one less thing to do right? Peonies like cold weather and need it to set blooms for next year. Besides, if you did mulch you’d need to remove the mulch the following spring because it could be a harbor for fungal disease.
Peonies are generally not plagued by pests. You may see ants and/or yellow jackets on your peony buds and blooms as they start to open. This is because the peony buds produce a sugary ‘sap’ that attracts them. Don’t bother spraying them -- you don’t need to put insecticides on your blooms and the ants are beneficial and will attack pests such as scale and aphids that might be present. I found out early on in my peony growing experience - through a couple of good stings - to watch out for the yellow jackets who also like to feed on that sap and sleep overnight in the buds and blooms.
Most peony diseases are fungal in nature and often result when they have been planted in a place that doesn’t get sufficient air flow or where fungal issues have been a problem in the past, since they are often soil borne. Fastidious pruning, cleaning and disposal in the garbage of fungal damaged leaves/stems and in some cases of heavy damage, removal and disposal of the entire plant is needed to combat fungal diseases. You do not want to put any of this debris in your compost pile where the fungus can thrive and spread itself to other areas of your garden where you use that compost as an amendment.
Here’s some of the more common that affect peonies:
Powdery Mildew - this common disease covers leaves with a white, powdery coating. Although it doesn’t seem to affect the plant's long-term performance, it is important to cut back the stems and dispose of all debris in the garbage when they go dormant in the fall.
Botrytis Blight - this can develop during wet grow seasons and causes brown or black patches on the leaves, cankers on the stems or stems that turn black at the base and fall over. Flower buds may turn brown and fail to open. Remove any affected leaves, stems or buds as they occur and dispose of them in the garbage. Deadheading and removing stems to the ground in the fall and disposing of those in the trash also helps.
Peony Wilt - is another fungal disease, not as common, that may be present in the soil. If it infects the plant, it will cause some of the stem tips on the plant to wilt. Don’t automatically assume this is the problem if you see wilt in your peony. Be sure the plant has been watered sufficiently first. Then, if you suspect it is peony wilt, you should contact your local extension office to find out how to get a test done. If it is infected, you’ll need to dig up and destroy the plant and be sure you don’t plant another peony in the same spot.
Peonies generally don’t like to be moved or disturbed. Because peonies are so long lived, they are considered ‘legacy’ or ‘heritage’ perennials -- plants that can be passed down from generation to generation of gardeners or within a family for sentimental reasons. This might be a good reason to divide a peony. Another reason might be because you want additional plants or if your plant becomes crowded. In an ideal planting location, you may not need to divide your peonies for 10 to 15 years.
The best time to divide peonies is when the plant is dormant -- in fall is best or early spring before new growth starts. Dig the plant and shake off the loose soil. Be careful because the tubers will break off fairly easily. If necessary, gently wash the soil from the roots with a hose. Separate the tubers, cutting with a sharp knife as needed and being sure each one has three to five buds or "eyes." Any damaged or soft tubers, or those showing signs of disease, should be trashed. Good tubers may be re-planted or shared with your friends, family and/or neighbors.
Peonies make great cut flowers! For best results, cut stems in the cool of the morning and when the buds are starting to crack open and showing color. Cut at this early stage, peonies will last 2 weeks in a vase with a bit of bouquet maintenance. Simply, remove the stems after 5-7 days, clean the vase and add fresh water, rinse and trim an inch off the bottom of the stems and place back in the vase. Peonies will also hold for up to 4 weeks if you wrap fresh cut stems in a damp paper towel and put them in a plastic bag in the refrigerator. When you want to use them, remove them from the frig, fresh cut the bottom of the stem and place in lukewarm water to wake them up.
My next blog, the last in the Peony series, will focus on Tree Peonies.