Lilac has long been a favourite garden shrub or small tree. It featured prominently in the old-style cottage gardens and in the great gardens of the big landowners alike.

It is a good cottage garden flower, because it readily produces suckers that can be dug up and used to grow new plants, and it is easily passed around, at no expense, between neighbours and friends.

Its popularity goes back centuries, when it was especially prized for its distinctive sweet perfume. Plants with good scent were greatly valued in former times.

The scent can fill a garden or part of a garden space, but it takes a big bush to generate a sufficient volume of scent to achieve that. It makes a good cut-flower and will last in water for a few days, bringing the scent indoors. If the woody stems are re-cut under water they are better able to draw up water and keep the blooms upright.

Last year saw a great display of lilac flowers, and this year it is exceptionally good too. The flowers of lilac have a distinctive pale blue-purple colour, and the name of the plant is used to describe the colour. There is some natural variation of colour and these variations have been selected over the centuries, developing a range of colour shades around the standard lilac.

Some are darker, some lighter in colour, including white forms. There are dark purples and wine-reds, and there are double-flowered varieties with very large and full flowers.

Souvenir de Louis Spaeth’ has single-flowered, dark-purple flowers. ‘Marechal Foch’ has single pink flowers. ‘Katherine Havemeyer’ has double-flowered blue-purple flowers. ‘Charles Joly’ has dark-purple flowers. These are all selections from the common lilac, Syringa vulgaris, the vulgaris bit just meaning popular – and not vulgar!

Lilac is a small tree or large bush, definitely not a shrub, as it is often considered. It looks very much at home in a country garden. It is long-lived and survives for decades in old gardens and often in old hedges.

It is easy to grow in any good garden soil, neutral or slightly limy, though it grows in acid soil too. The soil should be good and of reasonable depth.

A key aspect is drainage. Waterlogging in winter can cause bushes to die back. If the soil is heavy and rich, it tends to make the bush grow too luxuriantly, with lots of leaves and shoots and few, if any, flowers.

Responding to this growth by pruning is the wrong approach, as pruning simply encourages more leafy growth and further puts off flowering. Plants sold in flower in garden centres often cease flowering a year or two after they are planted out in the open ground and are no longer subject to the restricted root volume of the pot. But when the young plants have made a couple of metres in height, they begin to flower again, a couple to begin with, increasing in number. A shake of potash in spring helps to encourage flowering.

Ideally, the spot for lilac to flower best should be open and sunny with free-draining, good but not overly rich or fertile ground. Some garden compost could be dug in to open the soil – but no rich manure.

Time for staking flowers

Although it is a nuisance to have to stake flowers in borders, some kinds must have artificial support. Lupins, delphiniums, giant centaurea, altroemeria, crambe and others have a tendency to be knocked over in a few hours of a windy night in early summer. To prevent this, some suitable form of support is often needed: staking with canes, iron hoops or bushy, leafless branches. Be careful with canes and wear some form of eye protection. The extent of support needed will vary. If the garden is exposed, more plants will need support, or if feeding has been generous, or the soil is rich, plants might grow tall and be too soft to stand up under their own weight. In any case, the supports should be put in place in good time, before the stems, about to flower, suddenly break or are knocked sideways.

>> This week

Trees, shrubs and roses

To gain the benefit of a full growing season, pot-grown trees and shrubs can still be planted. It is important to water new plants if the weather is dry, and even with rain, there is usually not enough moisture. Spray roses for blackspot disease if they had it last year.

Fruit, vegetables and herbs

Sowing of many kinds of vegetable seeds can continue with good soil conditions, or in celltrays for transplanting. Thin vegetable seedlings as they reach a suitable size and take out weed seedlings at the same time. In a greenhouse or indoors, sweet corn and runner beans can be sown in the greenhouse for planting out in June.

Flowers

Tubers of begonias and dahlias and corms of gladiolus can be planted out where they are to flower. Watch for slug and snail damage, as plants are attacked as they come through the soil. Bedding plants should be regularly watered and given liquid feed to make good size. Space the plants well to give them room to grow.

Lawns

Grass growth has been fairly active, despite cool conditions at times. There should be no need to feed unless an old lawn is looking tired. Apply lawn feed or high-nitrogen fertiliser if needed. Do not use too much and repeat after eight weeks if necessary. Trim lawn edges and borders as flowering stems begin to extend.

Greenhouse and house plants

Feed and water greenhouse plants each week. Spray grapevines for mildew with a rose spray before flowering if it had the disease last year. Houseplants can be re-potted now, if they are pot-bound and inclined to topple over. Over-grown house plants can be cut back, well-watered and fed until they show signs of new growth.