Plant guide: peonies
The blowsy peony has had a huge resurgence in popularity recently, and rightly so. There are few plants with flowers to rival its majesty and sheer size, the tightly packed spherical buds unfurling in early Summer to reveal stunning multi-petaled flowers in pinks, reds and whites.
It’s a staple with us for an early flowering perennial, and we’re especially fond of it as it flowers around the same time as our little one’s birthday each year (the picture above was actually taken on the day before she was born!)
It has a reputation for being a little difficult to grow, and its true that the peony can be quite fussy about its planting location. But provide it with a perfect site (plenty of sun, not planted too deep) and it will reward you year after year with a seriously sumptuous floral display.
Botanical name: Paeonia spp.
Plant type: There are three different types of peonies: herbaceous peonies, tree peonies and intersectional peonies. Herbaceous peonies are probably the best known. They grow relatively close to the ground, with the flowers appearing over the herbaceous foliage, which dies right back below the earth each winter. Tree peonies are a larger shrub, with woody stems, that grow much higher above the ground and the woody structure stays in place over winter. Intersectional peonies are a cross between the two.
Growing conditions:
Peonies have quite particular demands for their growing conditions. Most importantly, they need a location with full sun, at least six hours a day. Grown in lower light conditions they will flower poorly, or may not flower at all. They also need a rich soil, one that is moist but well draining. Avoid soggy and waterlogged locations, where they will be miserable. Drier, less fertile soils can be improved by adding well-rotted organic matter, such as manure or green compost, either by digging it through an entire bed or by adding to the bottom of the planting hole.
Peonies are quite large plants, so allow an area of about a metre all around to give the plant a chance to grow. It’s best not to plant peonies together as it can increase their chance of getting fungal diseases, so if you want more than one in a border, spread them out and grow them as statement plants surrounded by other smaller planting. Also remember that herbaceous peonies will die back in the winter, so there will be patches of bare soil for the winter months. Positioning them next to plants that do something interesting at other times of the year – either evergreens or early Spring / late Autumn flowering for example – can help to detract from this.
How to plant:
Herbaceous peonies can be bought in containers or as bare root plants. Bare root plants (literally plants which arrive without any soil around their roots) should be planted in Autumn, and you should get them in the ground as soon as they arrive so that the roots don’t dry out. We always plant bare root as the plants are better value money for this way. So we can plant more peonies! We have bought bare root plants towards the end of the selling season, when prices are often reduced, and have got some great bargains. Farmer Gracy always have plenty of excellent quality varieties available as bare roots.
Container grown plants can be planted either in Autumn or in Spring, though these plants tend to be considerably more expensive.
The most important thing when planting herbaceous peonies is that they are not positioned too deep in the soil. Plants that are growing too deep down may produce a seemingly happy and healthy plant, but will generally fail to flower. And though peonies do have attractive foliage, especially when first starting to emerge from the soil in Springtime, it’s all about those glorious flowers…
If planting herbaceous peonies, the “eyes” or growing buds, from which the new shoots emerge, should be planted no deeper than 2.5-5cm below the surface of the soil. If planting a container grown plant, make sure that the top of the compost matches the surrounding soil level and isn’t any deeper.
Dig a planting hole a little wider and deeper than needed and mix in some well rotted organic matter at the bottom of the hole. Place the plant on top, check the level carefully and then back fill around the hole. Water in well.
Care:
Peonies usually take a little while to get established and happy in their new spot, so may not flower for the first year or so after being planted. They are long lived plants though, and can happily flower for about 50 years, putting out more blooms year after year, so be patient after you first plant one and it will reward you for a long time!
Water them well for the first year after planting, especially in dry Summer periods. Once they’re well established, though, they can tolerate drought and shouldn’t need any additional watering.
They are hungry plants, so benefit from being applied with fertiliser in the Spring time. A balanced general purpose fertiliser will work well, always following the instructions on the label and taking care not to apply too much, as this can scorch the roots. Mulch around the plant in early Spring after fertilising, to conserve moisture over the Summer months. Take care to leave a space around the crown of the plant and don’t mound the compost up here – remember that all important planting depth!
Most peonies need to be staked, as the flowers are heavy and can pull the stems down. You can either use an attractive stake that stays in place all year, for example a metal plant hoop, or put some more temporary staking in place when they first start to appear in the Spring, such as bamboo canes and string. Make sure to do it before the plant has grown too much, or you can damage the stems.
As peonies first come into bud, the tight spheres of flower petals can often be seen crawling with ants. Many gardeners worry about the ants and want to get rid of them, but they’re not actually causing any problems, and in fact could be helping the peony. The flower buds excrete a sticky, sugary substance that the ants come to eat. The ants don’t damage the flower in any way, and this could well be a reciprocal arrangement as they will attack any other predators, such as aphids, which would cause damage, in order to protect their food! So, don’t worry about trying to remove ants, if you see them crawling over the flower buds. They usually leave of their own accord once the flower starts to open.
One problem that does sometimes occur with peony buds, is that they fail to open into a flower. This is known as “flower balling” because the flower literally remains as a ball. It usually happens in wet weather, when the outer petals have become soaked through, but then dried in the sunshine and fused together. If this happens to your peonies, there a few preventative measures you can take. Firstly, remove any buds that are fused like this, so they don’t catch fungal diseases which can spread. Then make sure there is good air circulation around the plant, which will help to make sure any wet parts of the plant dry out faster. Also make sure to water in the evening, watering the soil rather than the plant itself.
Once the peony flowers have gone over – that is once they have bloomed and died, deadhead them to encourage repeat flowering.
Cut the foliage of herbaceous peonies right back down to the ground in Autumn as the foliage starts to die. This helps to reduce the risk of disease.
Uses:
Peonies make brilliant cut flowers and can last a long time in a vase. It may take around three years before a plant is established and happy enough to make enough flowers for cutting, so be patient with new plants and don’t cut the flowers for the first couple of years.
If cutting for the vase, pick the flowers before the buds have opened. They are perfect for cutting when they are in a squishy marshmallow bud stage: when the bud hasn't yet opened but feels squishy like a marshmallow! The flowers will open over the next few days, which leads to the longest vase life. (Buds that feel hard like a marble won’t open, and flowers that are already blooming when cut will fade very quickly…)
Grow with:
Peonies have a really traditional cottage garden look and go well with other similar plants, particularly in a mixed border with some evergreen structure. Try them with roses, irises, alliums, geraniums and Alchemilla mollis for a romantic plant combination evocative of classic English gardening style. They work equally well in more modern combinations as well, looking especially good alongside grasses, such as Stipa tenuissima or Pennisetum, which give an airy feel, full of movement.
Our favourite varieties:
‘Sarah Bernhardt’ is our “go to” peony, it produces huge balls of highly scented light pink flowers and has good disease resistance.
‘Coral charm’ is also fabulous, this one is a bright salmon pink when it first opens, fading to a lighter coral colour. We often grow a few extras of these in pots to give as gifts.
