Peonies have long been popular in country gardens, especially those with large rounded, dark-red, double flowers over deep-green, lush foliage. Old-fashioned pink and white-flowered plants are often seen too. Typically, the plant forms a great mound of foliage with sumptuous flowers dotted over it. The flower petals are wonderfully silky, with a sheen and a fresh newness about the flowers that speaks of early summer. Many people still call them “peony roses” because they resemble fully double roses, although they are not related, and have no connection with roses.

Apart from the old-fashioned kinds, there are some lovely named varieties, that also appear, more recently planted. Bowl of Beauty has deep pink outer petals and a boss of cream-yellow slender stamens. Avalanche is white with a hint of yellow and a fleck of red sometimes, and it has good fragrance. Some peonies are scented, usually those of lighter colour, but many are not. Duchess de Nemours is fully double, white-flowered, and Sarah Bernhardt is fully double, frilly, and soft pink. All of these are semi-double flowers or double-flowered. Claire de Lune is a single-flowered yellow variety, early to flower, a hybrid of the very beautiful species Paeonia mlokosewitschii, which also has beautiful foliage. Sea Shell has large single lavender pink flowers and sweet scent. White Wings has single flowers, very large to over 20cm across, white with a touch of yellow and fragrant.

Peonies can take a while to settle in after planting as they are not too keen on being disturbed. Plants bought growing in pots are easier to get started than those in plastic packets. Some nurseries offer bare-root plants which should be replanted right away. If it is a bad position, the time to move a peony is early autumn or early spring. They start into growth early in the year and it is best to move them before the leaves begin to push out. The plant has thick tuberous roots that supply food for early season growth. Peonies dislike wet soil, but they like rich, fertile, humusy, well-drained soil that does not dry out, and they can tolerate dry soil, though making weak growth and poor flowering. The common double-flowered kind has a tendency to flop over, particularly in an open garden and if the weather is wet and windy. Over-feeding makes this problem worse, but some feeding is needed to encourage more flowers.

The peony is one of the most durable garden plants, known to pass 80 years in the one spot. Even somewhat shaded, it survives, though it will not flower if there is too much shade. As shrubs and trees grow outwards, they reach out over peonies that were previously in full sunshine. Increasing shade is a common occurrence and explains why some old plants produce masses of leaves each year but few, if any, flowers. The solution is to lift the plants and move them to a sunny position. If you have an old peony that has not flowered this year, first consider if it is too shaded or whether it just needs feeding and a mulch. If the flower buds did not form, it may have virus disease which can cause discoloration of the foliage with marks and rings, and there is a peony wilt too that rots the flower buds and developing flower stems. Grey mould can kill buds in a wet summer. If an old plant is moved to a sunny position in fertile ground and does not flower in a couple of years, it is likely that disease is the problem and healthy new plants should be bought. It is a chance to buy some new varieties!

This week

Flowers

Bedding plants can still be planted, and containers and baskets planted up. There is still plenty of time for them to give value through summer into autumn, especially if large plants in individual pots or cell trays are used. Watch for slugs and snails in beds in the first few weeks after planting.

Trees, shrubs and roses

Despite recent heavy rain, young trees and shrubs still can struggle for moisture and need to be checked for signs of drought, principally poor leaf growth. Water well to go deep. Continue to tie in the new shoots of climbing roses so that they will be in the correct position for training later.

Fruit, vegetables and herbs

Repeat sowings of vegetables sown early, such as lettuce, radish, rocket and peas, could be made. Thin out vegetables that have reached suitable size, and control weeds early. There is still time to sow Savoy cabbage varieties. Use herbs as they come ready or trim back.

Lawn

Lawns have benefitted from the increased wet weather after quite a dry time in May. If growth is poor, even after recent rainfall, some fertiliser will boost growth. Now that the soil is moist, lawn weedkiller can be used. If you like a wildflower lawn, do not use weedkiller as it will kill wild flowers.

Greenhouse and house plants

Continue to feed greenhouse plants every two weeks to get good growth before midsummer and water well. Control pests such as greenflies, because the natural predators and parasites of pests are generally absent within a greenhouse. Display flowering greenhouse and house plants.

Rose blackspot

With the return to showery weather, there are already signs of an increase in rose blackspot disease. This is a severe disease of roses, especially bush roses in a rose bed, but it can affect climbers too. While a few spots are not significant to the vigour of the plants, the numbers quickly increase in summer and the older leaves begin to yellow and drop off. Leaf drop continues as the disease progresses until the rose bushes are stripped bare, only flowers remaining and often the plant, hardly growing, struggles to open some of these. Spraying with rose spray is effective but must be started in spring to give good control. Take note now of the roses worst affected and consider replacing them with more resistant varieties, though not in the same positions to avoid rose replant disease.