With my peony buds positively fat and ready to burst open any day, I thought it was a great time to revisit this interview on how to grow peonies well in our region. They were among my mother’s favorite flowers, and are without question among mine. Enjoy!
Some plants are rooted more deeply into each gardener’s personal memories than others – the plants they grew up surrounded by, the plants grown by people they loved perhaps. Peonies are among those memoried plants for me. Each June, when I was a child, my family’s dining room table would be graced by a Wedgewood-blue urn-shaped vase overflowing with opulent and sensual pale-pink and pink-flecked-white blooms of sweetly-scented double peonies grown by my mother. In this annual June arrangement, the rounded, ruffled, voluptuous peonies were accented by delicate little spires of red coral bell flowers. The composition of this arrangement – its size and shape and colors and scent – marks for me, still. the height of elegance and beauty.
What I didn’t appreciate as a girl was what a wonder of a plant peonies were for my mother, a professional gardener and florist. Gardening at 8,000 feet in elevation along the front range of Colorado’s Rocky Mountains, with cold winters, very dry summers and creatures of all kinds helping themselves to her flowers, my mother faced some plant-choice challenges – but peonies met them all. And they can meet all of our Northern Californian gardening challenges as well, Carolyn Melf assures us, including the challenge of deer! Deer don’t touch them.
Carolyn is the owner of Iris Spring a display garden and seasonal, by-appointment nursery specializing in both iris and peonies in Paradise, California. While Carolyn says she is “just a peony beginner,” I have purchased peonies from her for the past 4 springs, and recently heard her present on the history and cultivation of herbaceous peonies. Carolyn – a long-time home gardener, dedicated Paradise Garden Club member, recently-graduated Butte County Master Gardener and professional grower is not only very knowledgeable but always learning – and always very generous with her knowledge. Photo: Carolyn Melf at her garden and nursery, Iris Spring, in Paradise.
The Paeonia genus is comprised of 30-plus species of flowering herbaceous perennials and deciduous woody shrubs, which are known as tree peonies. While there at least two California native peonies – P. californica and P. brownii – the most common garden varieties are the herbaceous and tree peony hybrids originating from Asia. Photo: The California native P. brownii blooming in the Warner Mountains.
History of the Peony
Peonies have been grown in Japan and China since the 7th century. They have been in the gardens of Europe since the Crusades. For 200 years Americans have grown peonies. Thomas Jefferson grew peonies at Monticello. Here in California, the first Asian peonies probably arrived in a covered wagon as a little pieces of root.
Throughout the centuries people have thought of peonies as the most beautiful flower in the world. In ancient China they were the symbol of prosperity, coveted by wealthy Mandarins. The peony was the principle flower in the Chinese Imperial Gardens, and the Chinese called it ‘Sho Yo’, meaning “most beautiful”. To buy one prized peony in the Imperial period, the price was as much as three houses. Some peonies were included in the dowry of a bride. Modern day herbaceous peonies generally sell $20-$65. All parts are toxic.
The most commonly grown peony is the herbaceous hybrid of Paeonia lactiflora. It does well in a wide range of soil types and climates – hardy from the coldest zones to zone 8. It does require some winter chill to bloom and thrive. The pink or red stems grow 2-4 feet. Flower colors include white, yellow, cream, coral, pink, rose and red. The herbaceous peonies die to the ground in winter, and begin to show their little red buds – also called ‘eyes’ in early March, followed by their deep green clump-forming foliage.
Peonies are grouped into five primary types – which are sometimes confusing – but based generally on their bloom form.
Fully Double – in which the bloom completes the process of doubling. All the stamens and carpals have developed into petals resembling the guard petals. Examples include: ‘Shawnee Chief,’ ‘Raspberry Sundae,’ ‘Bess Bostick,’ and ‘Henry Sass.’
Semi Double – in which flowers have prominent pollen-bearing stamens interspersed with large petals. Examples include: ‘Ann Berry Cousins,’ ‘Coral Charm,’ ‘Lovely Rose,’ ‘Cytherea,’ and ‘Red Red Rose.’
Bomb – in which the bloom has smaller petals that form a mound or bomb in the center of the larger outer petals of the same color. Examples include: ‘Big Ben,’ ‘Pink Derby,’ ‘Red Charm,’ and ‘Mr. Ed’ (a unique pink & white).
Japanese – in which the doubling process has begun. The stamens have widened into staminodes that may look like shredded petals that are surrounded by larger outer petals. Japanese form peonies stand up well in weather. Examples include: ‘Doreen,’ ‘Gay Paree,’ and ‘White Sands.’
Peonies grow from an underground crown and have either pointed or large and bulky roots, similar to the shape of a cigar. In late winter the elongating stem of a crown bud or “eye” which is firm and red emerges and splits, allowing a leafy shoot to grow. Flowers are terminal with 1-2 lateral buds.
In Northern California, peonies bloom from April through May and into June at higher, cooler elevations. At blooming time, plants are fully developed and will not add any new stems or leaf growth. This is why it is important to not disturb the “eyes” while weeding. During summer, the plant is forming stem buds at the base of the stems and storing food for next spring’s growth. These buds are the source of new stems for next spring. Photo: Peonies form nice wide clumps as they mature.
By September, peonies are ready for dormancy. Peony tubers begin sending out feeder roots and root hairs develop before the coldest weather and begin growth again in early spring. The length of dormancy varies with each variety.
Peonies in interior valley portions of Northern California like morning sun and some afternoon shade.
In order to bloom well, most peonies need around 400 hours of 46 degree soil temperature. It is important to choose early or mid bloom season peonies in our mild climate. Varieties that are bred to bloom late in spring may have difficulty opening due to the rapid change in temperature from spring to summer heat.
Carolyn suggests it is best to choose plants in the spring to assess desired characteristics and color. Some older varieties need staking with supports. Newer cultivars are bred to have stronger stems that do not need staking because of thin stems of very heavy blooms. Choosing from blooming plants in person is superior than relying on photographs in catalogs. Peony roots should have 3-5 eyes. Each root crown should have 2-3 roots measuring 1/2″ or larger in diameter and 6-8″ long. Many peonies have fragrances varying from rose to hints of citrus. While some catalogue descriptions will note if it is very fragrant or only slightly or not at all, it is easier to assess this in person. Thicker petals stand up to weather better than thinner petals found on some older varieties. Photo: The garden at Iris Spring, a peony bloom bending over the little creek spring creek that runs through the garden.
Potted peonies may be purchased or planted any time. Select pots with 3-5 shoots with strong healthy looking foliage. Whenever possible, check out your peonies while they are growing in the field, preferably with similar growing climate and conditions.
Carolyn’s Recommendations for Planting and Care of Peonies in Northern California
A peony blooms for 7-10 days. Mix early and mid to late bloom peonies, this way you can have about six weeks of blossoms from early to late spring. Early and mid-season peonies in single, semi- double, and Japanese shapes are recommended. They have less difficulty opening than fully double peonies. Late blooming varieties may result with partially opened buds due to warm weather. Photo: One of Carolyn’s favorites – P. ‘Red Charm.’
Planting: Peony plants are attractive as foliage even after they bloom and their foliage turns a lovely golden in the fall. They are long lived plants–sometimes living 50 years if left undisturbed. Plants may outlive the original gardener, so carefully choose its location!
Plant peony roots September through October. The earlier time allows the roots to settle and to develop. They will be less likely to suffer from freezing temperatures. Choose a location with at least half a day of sunshine. In our warm climate, morning sun and afternoon shade is ideal. Make sure the soil is well aerated. They hate soggy feet!
Be careful to not injure the eyes or roots. Keep roots moist until they are planted. Soak overnight or several hours prior to planting. “Do not dig a .50 cent hole for a $20 plant!” Carolyn emphasizes. Dig a hole large 18″ x 18″ deep. Mix organic matter, compost or peat moss with the soil removed from the hole in a ration of one part organic to two parts soil. A half cup of blood meal and a half cup of bone meal may be added to this mixture. With this mix, fill the hole to half its depth. Plant the peony crown so that the eyes are just below the surface level of the surrounding ground. Continue surrounding the plant with soil. In Northern California this means no more than 1/2″ below the soil, and if the sprouting “eyes” of the bulbs are planted deeper than this they may not bloom. Slightly pat down the soil and then add a gallon or so of water. The water will help compact the soil and helps prevent the plant from settling. Surround growing area with mulch to deter weeds. Plants should be spaced 3-4 feet apart. Closer spacing will result in crowding. Since peonies are long lived, they perform best if left undisturbed. Photo: P. ‘Lovely Rose’ from Iris Spring.
Watering: Peonies are drought tolerant but still require water. They need lots of water during spring growth, especially during their bloom cycle. It is best to apply water slowly for a longer period of time to penetrate the soil to greater depths. Continue to water moderately during summer and fall, about once every 1-2 weeks, about the same as for bearded iris.
Withhold water from September to October to force dormancy.
Fertilization: Lightly fertilize with a tulip/daffodil bulb fertilizer or 10-20-20 at the time of emergence and after bloom. The spring fertilizer should be applied after the new shoots begin to emerge. Never apply the fertilizer directly over the center of the peony crown for this may burn the eyes. Sprinkle the fertilizer in a band around the plant about 8″ and extending out to 18″ from the center of the plant.
Staking: Wind or rainy conditions may cause the heavy flowers to droop, especially fully double varieties. Ideally the gardener should choose a variety with strong stems. Spring is the best time to insert specifically designed peony supports. Choose heavy duty two ring, thick metal gauge supports. They usually measure 30″ high with an 8″ diameter top ring and a 14″ lower ring. Older varieties may require staking. Photo: P. ‘Paula Fay’ from Iris Spring.
Types of stakes: There are a variety of takes including solid twigs from your own gardens prunings with twine wrapped loosely around the plants to support the heavy blossoms. You can also find double ring stakes at garden centers and hardware stores; tomato cages will also do the trick.
Insects: Ants and peonies seem to go together. Ants do not feed on peonies and their presence is not necessary to open buds. They are attracted to the sweet excretion emitted when the sepals begin to separate. After they have mined the sugary food source, they usually leave the plant. Ants can be beneficial by feeding on fleas, termites and other garden pests. Keep peonies and other plants at least a foot from the foundation of a house to reduce ant foraging and nesting. Dip flowers in water to remove ants before creating a bouquet. Photo: An ant-happy peony bud.
Thrips are usually unseen because of their small size. They are usually found on light colored flowers. Their feeding damage is often unnoticed because of the plentiful amount of foliage in the large flowers. Dispose of spent blooms to reduce this problem. Thrips can be beneficial as a predator of spider mites.
Slugs can be controlled with a low dish or pie tin containing beer. Place container near level with soil, giving slugs easy access. Place containers around peonies overnight and repeat nightly until slugs are controlled. The slugs will seek out the beer and will slide in for a drink. Another method to deter slugs and snails is to spread 1″ layer of oyster shells around peonies that are about 1 foot tall. This is also recommended for hostas.
Disease-Fungal and Bacterial Problems: Botrytis turns flower buds black and causes them to drop, unfurled shoots to brown and droop. This condition is found during a long, wet, cool Spring season. Control by cutting away diseased or damaged foliage, disposing away from the yard. Keep area around the peony free from dropped, decaying foliage to prevent the spread. In late fall, cut down any blight infected plants to 1 inch above the soil. Cutting the plants down will break the cycle.
Powdery Mildew appears as a while flour-like substance on leaves, flower buds and blooms, which can sometimes be accompanied by a distorted leaf shape. At the earliest possible recognition of mildew, spray with neem oil. The best prevention is to have good air circulation around the plant and a sunny location.
The plant is too deep. The eyes need to be only 1/2″ below. Raise up the entire -plant to the proper depth. The plant has too much shade – trim other vegetation or relocate the peony. The peony is too young. Be patient, it takes about three years to produced mature flowers. The plant is getting too much or too little fertilizer- fertilize 6″ from the crown at the time of emergence and after bloom with tulip/daffodil bulb fertilizer. Never use grass or liquid fertilizer.
Carolyn shares an old peony adage:
The first year it sleeps (develops roots)
The second year it creeps (develops roots and stems)
The third year it leaps (it bursts into many full size blooms and stems)
Moral: be patient with the peony, observe its few needs and it will reward you with a gorgeous, long lived plant that you can pass on to your next of kin!
Iris Spring Garden and Nursery is open most weekends, Thursday – Sunday from early May through early June and by appointment otherwise. Call to confirm hours! Open weekends are a wonderful time to visit and see Carolyn’s many peonies (and iris) in bloom! Her motto on Irispring.com is Make a Peony a Part of Your Life!
Carolyn Melf / Iris Spring Garden 122 Valley View Drive Paradise, CA 95969 530 / 872 – 7771 www.irispring.com
For more information on peonies, try:
The American Peony Society: http://americanpeonysociety.org/
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In a North State Garden is a weekly Northstate Public Radio and web-based program celebrating the art, craft and science of home gardening in Northern California. It is made possible in part by the Gateway Science Museum – Exploring the Natural History of the North State and on the campus of CSU, Chico. In a North State Garden is conceived, written, photographed and hosted by Jennifer Jewell – all rights reserved jewellgarden.com. In a North State Garden airs on Northstate Public Radio Saturday mornings at 7:34 AM Pacific time and Sunday morning at 8:34 AM Pacific time. Podcasts of past shows are available here.