Spring memories sustain us at Cricket Hill Garden in the stark cold landscape of winter. Conjure that peony blossom, inhale deeply, and one can be lost in the fragrance of those luscious petals.
Winter is the time for planning and dreaming of the garden, remembering the past season and what was successful and what needs to improve. If we are to consider peony plants as part of the broader landscape plan, the questions of placement and design are numerous.
This is especially true as one considers the subtle, yet distinct characteristics of peony varieties. When planning peonies in the landscape, we may choose to consider the color, form and fragrance, as well as bloom time and foliage.
Before adding peonies to your landscape the first consideration is whether the location has the right amount of sunlight.
- Planted in the deep shade, almost all peonies will grow weakly.
- Tree peonies will grow vigorously in the full sun, but the flowers fade quickly. Some cultivars are also susceptible to leaf scald in the summer sun. For these reasons we recommend planting tree peonies in a partially shaded location. An eastern exposure, or in a location with dappled sunlight is ideal. Five to six hours of sun makes them grow well.
- Herbaceous and intersectional or itoh peonies both need as close to a full day of sun as you can provide, or a minimum of 6 good hours of sun. Without this, they will be weak and not bloom well.
A mixed garden bed with tree and herbaceous peonies would be ideal in 6 hours of sun.
Sometimes a garden bed will have different areas of more and less sunlight due to the shade of trees or a building, so plant your peonies accordingly. Tree peonies in the shade protected areas and herbaceous in the more sunny spots. The old garden adage holds especially true for peonies, ‘ Right plant, right place.’
The other necessity for peonies is good soil. Peonies planed in poor, unimproved soil will not grow or flower well.
- All types of peonies need fertile and well drained soil.
- Peonies appreciate a soil high in humus and organic matter. Peonies also need a range of trace minerals to bloom well. A neutral pH of 6.5 is optimal. Peonies planted in poor soils with a low (acidic) pH will never thrive or bloom satisfactorily.
- Never plant peonies in an area where there is standing water at anytime other than the very early spring when the ground is still frozen. Waterlogged soil will suffocate the roots of peonies and is a leading cause of a gardeners failure with peonies.
If your desired planting site is not already suited to growing peonies, do not despair, advanced preparation can make many areas of the garden hospitable to peonies. Poor soils can be amended with compost and rock powders for minerals. Ground limestone will raise the pH to the desired level. For soggy areas, making raised beds will ensure good drainage. For detailed information on soil preparation for peonies, see our blog post
Within the three types of peonies- tree, herbaceous and intersectional hybrids– there is great diversity of bloom time, flower color, form and fragrance. Plant habit and size at maturity also differ. One may even delve into the nuances of shades of color and foliage form. Peonies can be understood and appreciated on a number of levels.
Tree peonies (Paeonia suffoticosa, Paeonia lutea, Paeonia rockii and other species) are very long-lived, relatively slow growing deciduous woody shrubs which bloom in the mid-spring. Our collection of several hundred tree peony cultivars usually blooms over a six week period, from the first week of May to mid-June in our zone 6a Connecticut climate. Tree peonies will grow and flower well in USDA zones 4-9.
The longer the winter season lasts, the later the flowers will appear. In northern climates, such as Minnesota and New Hampshire, tree peonies bloom about a month later than we see them here in Connecticut. In warmer climates, such as the Carolinas, tree peonies bloom in April, and some places in California see their tree peonies open in March. It all depends on how long the winter season lasts and the buds are dormant.
Tree peonies blossom in a range of colors, from pure whites, pinks, purples, to deep wine reds, bright yellows and silvery apricots. Flowers are formed in a variety of shapes, from elegant singles to massive ‘thousand petal’ doubles.
Tree peony plant habit can be as compact as 2.5′ tall by 3′ wide or a large as 6.5′ tall x 5′ wide. Most plants do not reach their mature size until 10-12 years of age.
The woody stems are strong on most all cultivars, especially the Chinese tree peonies. We have seen older Japanese tree peonies produce weak stems which do not hold up their flowers. Some types are genetically weaker and there is nothing to do but stake them, or avoid growing them. All of the tree peony cultivars we grow and sell do not need staking, so let our experience be your guide.
Tree peonies should be planted 4-5′ apart on average. The larger growing rockii cultivars, such as Snow Lotus, Purple Butterfly in the Wind, Black Tornado & others need 6′ apart to spread.
Try to plant at least 3′ away from foundations and 6-10′ away from trees and large shrubs. The roots from most trees will interfere with the tree peony roots and take away moisture and nutrients. Smaller perennial plants, bulbs and ground covers may be interplanted, but keep the area around the immediate base of the plant open to allow for good air circulation.
Herbaceous peonies are very hardy, long lived and relatively carefree perennials.
This group includes over twenty different species; notably Paeonia lactiflora, Paeonia japonica, Paeonia macrophylla as well as hybrids derived from crossing two or more of these species. There are literally hundreds of named cultivars, though many are no longer in production, or are very hard to find.
Herbaceous peonies can be grown easily in USDA zones 3-8. In zone 9, some micro-climates will support the chill requirements needed to bloom.
The various species of herbaceous peonies and their hybrids bloom over a very long period in the spring. In Connecticut, zone 6a, the earliest types bloom in late April and the late season plants bloom in the middle of June. So by choosing different kinds, you can extend the range of bloom period. The majority of herbaceous peonies grown today will be the lactiflora type and these bloom in the mid-to-late period. We see these from late May to mid-June.
Herbaceous peonies come in a wide range of colors and forms. Since they lack the strong woody stems of tree peonies, many herbaceous peonies with large double flowers tend to flop over if left unsupported in the garden. We tend to avoid peonies with these habits and offer peonies with better stem strength. Over our 25 years of growing, we have grown out hundreds of named variety herbaceous peonies. Many peonies bred for the cut flower trade do not make good landscape plants; the stems are weak. This problem can be avoided by selecting cultivars with stronger stems and more proportionate flowers. All of the herbaceous types we currently grow offer better stem strength and most do not get any support in our display garden. The most we will do is a few well-placed bamboo sticks at cross angles to support the heaviest flowers in bloom.
After the bloom period, most herbaceous peonies will retain their lustrous deep green foliage into September, though some species type loose their foliage during the summer. In the fall, herbaceous peonies, like other non-woody perennials, are cut to the ground in the garden clean-up that should be done after the freeze.
Intersectional or Itoh peonies are crosses between tree and herbaceous peonies. They are the newest darlings of the peony world. Most were hybridized late in the 20th century and new types are still being introduced. They exhibit the flower forms of a tree peony on a herbaceous bush. Plants grow to an average size of 3-4′ tall and wide, though some are shorter. Blossoms come in a range of colors, from lemon yellow, to lilac and scarlet. Most are sized from 7″ to 10″, making them quite extraordinary. Stems develop good length and flowers can be cut with 12-16″ stems for arrangements. Fragrance is good, usually with a lemon scent or light spicy-sweet fragrance. They are not as fragrant as the best tree peonies, but are valued for their color palette and ease of growing. They are grown very much like the herbaceous peony, with a full day of sun, or at least 6 hours.
The bloom time of intersectional peonies coincides with the end of the tree peony bloom and the beginning of the lactiflora type herbaceous peonies. An individual intersectional cultivar will bloom over a long period, with primary buds opening first and then secondary buds opening a week later.
Herbaceous and intersectional or itoh peonies should be planted 3′ apart on average. The same spacing is suggested from foundations and tree roots for the same reasons of competition and crowding. This type of perennial planting may look sparse for a couple of years and that is why we suggest trying non-agressive perennials, annuals and bulbs as an interim step to getting your garden bed to look more full and balanced. We have heard of professionals who bend the spacing rule and crowd more plants into the garden bed to make it look full immediately. This means that in just a few seasons the bed will be overcrowded and plants will have to be moved. Overcrowding also makes for more fungal problems because the air does not circulate and foliage is more likely to stay wet and breed disease.
Below is a rough breakdown of the bloom times of the various types of peonies. During very warm springs this period is very compressed. We have listed here a few cultivars for each bloom period. In the cultivar descriptions for our tree, herbaceous and intersectional peonies on our website we list the bloom period. (Dates given in parentheses are when a given group of peonies will bloom in our USDA zone 6a garden in Connecticut)
Very Early (late April to early May in northwest CT)
Species herbaceous peonies:
- P. japonica
- P. emodi
Early (Second week of May in northwest CT)
Hybrid herbaceous peonies:
- P. officinalis ‘Rubra Plena’
Early Chinese tree peonies:
- Supreme Pink
Mid-Peak Bloom (Third week of May to early June in northwest CT)
Mid-Peak Chinese tree peonies:
Rockii Chinese tree peonies:
- Black Tornado
Japanese tree peonies:
- King of Flowers
Lutea hybrid tree peonies:
- Happy Days
Late (Memorial Day to second/third week of June in northwest CT)
P. lactiflora herbaceous peonies:
Intersectional or Itoh hybrid peonies:
- Old Rose Dandy
With the sun and soil requirements understood, and a good outline of what to expect in the three types of peonies, it is apparent that they can be used in numerous ways in the landscape.
Trees and large woody shrubs set the boundaries of a landscape, they give it depth and breath. Upon this backdrop, perennials and annuals are added; these smaller plants give a landscape texture and detail and purpose.
Plants define areas of the landscape and help people connect to it through colors, fragrance, sunlight and shade, fruit and flowers. The contemporary American gardener enjoys creating a space that enhances their home and defines a place to relax and enjoy nature.
Peonies in Borders and Devoted Beds
In composing a border with peonies, keep complementary heights, colors, bloom times and fragrances in mind. Tree, herbaceous and intersectional (itoh) peonies can all be combined in a border with about six hours of sun, but they should be planned with their individual attributes of size in mind.
We like this combination because of the longer bloom period that is achieved by planting the three types of peonies together. Most climates can see a 5 to 6 week range of bloom once plants are established. Tree peonies bloom first, early to mid-season herbaceous and itohs next, then the late blooming herbaceous finish the show. At Cricket Hill Garden, we see early May to mid-June bloom most years. High heat in late May or early June will shorten the season for us.
For landscape plantings, plants which hold their flowers well and continue to have good foliage throughout the season are good candidates. The American Peony Society created the Award of Landscape Merit in an effort to help growers and gardeners select herbaceous and intersectional peonies with “superior ornamental value, overall appearance in the landscape and throughout the growing season, and reliable performance across North America”. This current list is by no means comprehensive of all cultivars that meet these criteria. Nonetheless, it is good start to identify reliable cultivars with strong stems that hold their flowers well. We hope that in the future the Award of Landscape merit may also be bestowed on outstanding tree peonies.
Most gardeners have a limited space to work with and existing plants to consider. Mixing peonies with other perennials and annuals allows for variance in texture and color for the entire season.
As much as we advocate using peonies in the landscape, we also readily admit their shortcomings from a landscape perspective- they only flower for a relatively short period in the spring. However, with an appreciation for the various foliage forms peonies can provide an interesting textured background for summer flowing annuals and perennials.
Tree peonies all have three point compound leaves. Some however a much finer than others. Also, tree peony leaves can be disgusting as either having glossy or matte green foliage. Herbaceous peonies also display a wide range of variety within a basic form of an elliptical leaf. Intersectional peonies all have glossy green foliage with a leaf shape which resembles the P. suffoticoa type Chinese tree peonies.
Some species and hybrid herbaceous peonies die back during the heat of mid-summer. Herbaceous peonies like Early Scout, and P. officinalis ‘Rubra Plena’ should not be planted in an location where it’s early foliage loss will create a hole. Instead plant a cultivar which looses its leaves early at the end of a border or bed.
As a general rule, herbaceous and intersectional peonies make better cut flowers than tree peonies. This is because the long, 12+ ” herbaceous stems of these two types are ideal for flower arranging. Many of the classic P. lactiflora herbaceous varieties such as “Sarah Bernhardt” and “Festiva Maxima” were developed for use in the European cut flower market. We get so many questions from gardeners who have inherited peonies in their garden or purchased unnamed cultivars and then struggle with these weak stemmed flowers. Using peony rings to prop up them up is a lot of extra work. If a gardener is so inclined and if space allows, a section of the garden, or even an island away from landscaped vistas, can be set aside solely for growing peonies with large flowers. Cutting these and bringing them inside to enjoy as soon as the buds are partly open is the only sure way to keep these gorgeous, but weak stemmed varieties from flopping over after the first rain.
Peonies as Display Specimens
Using peonies as the focal point of an island bed in the middle of a lawn or in a small raised bed is ideal for showcasing tree peonies. Tree peonies grow on average 4’ tall and wide. The majority grow in this size group, though some grow only to 3’ tall. The largest growing tree peonies, the rockii type from northwest China can reach 6.5′ tall and 5′ wide at 10-12 yrs. Older plants develop a sturdy, majestic structure. The foliage is finely textured and contributes to the interest after the blooms have past. If space permits, consider a long blooming peony island with taller growing tree peonies in the background and lower growing herbaceous or intersectional in the front.
Along Fences, Walls and Foundations
Here peonies are given a backdrop that does not compete for moisture or nutrients in the soil. Apply the same principles of space and sunlight, color and form, and size of plants when planning a peony border against fences and stone walls.
Intersectional peonies make good candidates for this use with their uniform height and long bloom period. The herbaceous stems have the advantage of re-growing every year and thus can be planted near walkways or driveways, sparing the plant any snow damage in the north. Tree peonies have to be placed away from heavy snow loads, as the branches could be damaged if heavy snow is piled on top.