Summer is in full swing now and traditional border favourites such as lupins, delphiniums, iris and peonies are filling well-planned gardens with colour. Of all these, I find peonies the easiest to please and the least work because they bloom reliably every year, are hardy and they live for years, indeed decades. Unlike the bedding plants we buy every year, peonies really are investments and they get bigger and better every year.
Unfortunately, gardeners sometimes have issues with peonies so I am going to deal with some of the common problems to reassure you about planting them in your borders and to help you resolve non-flowering peonies in your own garden.
But first, a few words about peonies. Although there are many different species, most of the herbaceous peonies we grow are hybrids of the Asian Paeonia lactiflora. Then there are shrubby peonies, that maintain a woody framework. Often called tree peonies or Moutan peonies, these are slow-growing, beautiful plants though rather gaunt in winter. The flowers are huge and not long-lasting, but worth growing for their exceptional beauty. Then there is Paeonia lutea, a yellow, shrubby peony that has comparatively small flowers but is easy to grow and often self-seeds. It is a lovely thing but the large, dead leaves don’t drop in autumn and it can look very scruffy in winter.
Then there are the Itoh peonies, which took decades to produce and are hybrids of tree peonies and herbaceous peonies. They retain some woody stems in winter but are largely herbaceous. They bring a new range of colours to garden peonies, including yellow and mixtures of shades and they flower longer, for several weeks, each summer. In addition, they rarely need staking, despite their large flowers. I have planted lots of these and they have all grown and flowered well. They are rather expensive, usually costing from £20 upwards, but they are worth every penny.
Can you plant peonies now?
Yes you can and it is a nice way to buy them, in bloom. But remember that they will need regular watering or they will die. Once their roots have grown from the potted rootball, into the border soil they won’t need regular watering unless in very dry periods or in very dry, sandy soil, but in the first year you must take care.
Can you grow peonies in pots?
In theory you can but peonies have large roots and need lots of feeding so I wouldn’t say they are are a great choice for pots. Also, they don’t flower for very long so you have a pot of leaves for most of summer. If you do want to try then use a large pot, at least 60cm wide and deep, and you must use John Innes No 3 compost. You could pop in some daffodils for spring colour. But, you may say, I am going to buy a peony that is growing in a pot! But the plant has been grown in a field, lifted and potted in winter and will only be in the pot for a short time. If you are growing a peony in a large pot I would chose an Itoh peony, and use a large pot – they have better foliage and make a neat dome of foliage.
Can I move peonies?
There is a common belief that peonies cannot be moved. This is nonsense and they can be moved. But do this in late autumn or early spring and make sure that the crown – the top of the roots – is no more than 3cm (1 in) below the soil surface. You can buy bare-root peonies in winter and these are very successful if you buy good quality roots. Cheap prepacked roots sold in supermarkets are often very small pieces and take many years to reach flowering size.
Why do peonies fail to bloom?
There are several reasons for this. They may have been planted too deeply in the soil. If so, they produce lots of leaves but no blooms. Sometimes they can be planted in shade. To bloom well, they need sun for at least half the day, ideally for most of the day. A little shade can help the flowers last longer but too much shade results in lots of leaves but no blooms. Sometimes a peony that did flower well, stops blooming. This can be because a neighbouring shrub or tree is causing more shade or you may have piled soil around the crown.
Why do buds die?
Occasionally buds form but turn black and die. This is peony blight, caused by a fungus that infects the buds, especially in wet springs. There is not much you can do about this apart from pick off the dead buds to prevent the disease spreading. It is not common every year and does not often affect Itoh peonies.
Plants don’t grow much
Peonies do like rich soil so make sure you feed them. Put some general fertiliser such as chicken pellets around them in spring and give them a yearly light mulch of compost or well-rotted manure, without mounding it over the crown.
