Peonies

Peonies

By Kathy Gray

If I ever had a National Collection, it would be that of Paeonia. I have loved these opulent flowers since I was a child and can remember making 'scent' from the petals of P. officinalis growing in our garden. Yes – I know the flowers are over quite quickly, but this genus has much to recommend it. Besides the beautiful flowers, the foliage is often most attractive, from the emerging shoots to autumn colour. The seed pods also offer more interest. Most peonies are hardy and long lived. They flower relatively early in the season and, as a consequence, are not so likely to be affected by drought; indeed they are reasonably drought tolerant – something I have witnessed in my garden during this summer.  They prefer to grow in sun, although there are some shade lovers, but they are not too fussy about soil conditions, as long as it is not a waterlogged site. 

Peonies suffer from few diseases, but are vulnerable to a fungus – Botrytis paeoniae, or peony wilt. Parts of the plant will wilt and, if it gets a hold, parts may turn brown or black and collapse; there may also be a furry grey mould. There are no specific chemical controls, so one should cut out the affected parts down to a healthy bud or, if necessary, to the ground. Do not put the affected parts in the compost as the fungus can survive for some years. The other pest is the larva of the common swift moth, which burrows into the ground to feed on the roots. If your peony is not doing well, it may be worth digging it up to inspect the roots, disposing of any unwelcome visitor; always do this before planting a new plant.

Peonies have a long history, having been used as medicinal plants for at least two thousand years. The ancient Greeks referred to them as the 'Queen of all herbs' and the Chinese considered the tree peony to be the 'King of flowers'. Perhaps rather unfairly, they called herbaceous peonies 'The King's Ministers'. The plants were highly valued in medieval times, when their roots and seeds were used extensively to treat a wide range of ailments and, in this country in the nineteenth century, the seeds were still being made into necklaces to ward off evil spirits. Their use in Traditional Chinese Medicine still continues, and although plants are grown expressly for this market, many wild tree peonies are dug up to satisfy the demand, with obvious consequences for the wild population.

For many years the genus was included in the family Ranunculaceae, and allied to plants such as Aconitum and Helleborus. However, they were placed in their own family, Paeoniaceae, in 1830. There are many species of herbaceous peony, with P. lactiflora being the source of thousands of different cultivated varieties, such as 'Sarah Bernhardt' and 'Bowl of Beauty'. 

Paeonia daurica subsp. mlokosewitschii, or 'Molly the Witch', with its primrose yellow flowers, is surely one of the stars of the garden. 

Herbaceous peonies have deep, tuberous roots that act as storage tissues, but should not be set too deeply in the soil as this may inhibit flowering. You can divide herbaceous plants – I have had the best success by waiting until leaf fall starts and then dividing. 

'Tree peonies' are, of course, shrubs with woody stems. These include plants such as the stunning Paeonia rockii, named after Joseph Rock, a botanist, explorer and plant collector. He found the seeds in 1925 in a monastery garden in Gansu Province, China. Unlike their herbaceous cousins, grafted tree peonies should be planted more deeply, with the graft union covered by at least 10 cm of soil.

Over the years I have grown a number of tree peonies from seed – something that I really enjoy. Ideally, seeds should be sown as quickly as possible after they are ripe, to avoid them drying and entering dormancy. You may find a mixture of black and red seeds in the pod – an attractive feature, but the red seeds are sterile. Peonies produce their root before their aerial shoot, so do not give up on seeds just because there is nothing to see. As a guide, fresh seed should produce its first root in the autumn after sowing, with the aerial shoot appearing during the following spring. Older seed may lie dormant for a year and need two periods of chilling before germination is complete. I currently have three peonies I have grown from seed within the garden and they are so beautiful. One I know as a 'Moutan Hybrid', which is, I guess, a form of P. suffruticosa, and my absolute favourite; it is beautifully scented.

So, do not be put off by people saying peonies don't flower for long. There are many that will be beautiful additions to any garden.