Lilacs are certainly among the most beautiful and fragrant flowers grown in area gardens and landscapes. The scent of lilacs is often described as intoxicating, captivating, alluring or heady. And for many of us, the beautiful clusters of showy flowers framed in lush, green foliage mark the start of the summer gardening season.
Most natural lilac varieties are of Asian origin. But a few, including the common lilac, Syringa vulgaris, originated in Eastern Europe. They were brought to Western Europe in the 1500s, by Ogier Ghiselln, Count de Busbecq, and presented to Ferdinand I of Austria as gifts from the Constantinople court of Suleyman the Magnificent. In 1579, Ghiselln brought shoots from those lilacs to France where they quickly became all the rage in Paris.
French nurseryman Victor Lemoine created the first intended vulgaris hybrid in 1867. His son and grandson continued to hybridize lilacs until 1953. Extensive cultivation and hybridization by French, Russian and North American horticulturalists have resulted in perhaps 30 known species of lilacs that account for as many as 2,000 cultivars. Modern day hybrids are available in a wide range of colors that includes purple, lavender, white, pink, red and yellow. Most grow to between 8 and 15 feet tall.
It is difficult to ascertain how far back lilacs date in this country, but there is no doubt that the common lilac was brought to the American continent by early European settlers, most likely prior to the year 1700 and perhaps as early as 1620. They were widely grown in the American colonies and are a part of this nation's history, cultivated by George and Martha Washington at their Mount Vernon estate, by Thomas Jefferson at Monticello and in America's first botanical gardens. Jefferson recorded his method of planting lilacs in his Garden Book, now part of the Coolidge Collection of Thomas Jefferson Manuscripts.
New Hampshire Governor John Wentworth also planted lilacs, before he was driven out of his Portsmouth home in 1775 for supporting British authority and imperial policies. Those bushes, planted circa 1750, are still alive today. In fact, it is not at all uncommon to find lilacs, which can live for hundreds of years, in rural landscapes beside centuries-old homes and marking sites where homesteads and farmhouses once stood.
Lilacs have often been celebrated in literature and poetry. Classic examples include Walt Whitman's "When Lilacs Last in the Dooryard Bloomed," T.S. Elliot's "Portrait of a Lady" and Amy Lowell's "Lilacs," part of a collection that won the Pulitzer prize for poetry in 1926.
Because lilacs need a period of cold dormancy to set their buds for flowering, they grow and bloom well in colder regions, like ours. And although they are rather adaptable and easy to grow, they will perform best in good soil with adequate drainage (pH 6.0 to 7.0) and plenty of sunlight are provided.
It is much easier to propagate new plants from suckers taken from the base of existing plants than from cuttings. They should be given plenty of growing room. Providing 100 square feet (10 by 10) per plant is not at all unreasonable. Crowding will just cause them to grow tall and become leggy and unkempt.
There are differing schools of thought on maintenance pruning. To increase budding and reduce seed production, many gardeners remove spent blooms soon after the flowers have faded. Others claim there is no noticeable difference in the number of blooms that will result from pruning. And there are those that prefer to leave the flowers, so birds will have the seed to eat during the fall and winter months.
All agree, however, that annual pruning, as soon as the flowers have faded, although not compulsory, will keep the shrubs well shaped and healthy. This includes the removal of dead or broken branches (which can be done any time of the year), cutting back woody main stems by about one-third, and pruning branches back, as needed, to a bud or shoot that you want to favor. Older, thicker stems can be removed completely.
There are two approaches (that I am aware of) to successfully bring back old, neglected lilacs. Both seem a little extreme, but lilacs are tough. One calls for cutting one-third of the shrub to the ground soon after the flowers fade. Wait until the following year and cut the next one-third to the ground. Wait until the third year and cut the final third to the ground. With each cutting, the plant will put out new shoots until, at the end of the third year, all of the old wood has been replaced with new growth.
The other method calls for cutting back the entire dormant shrub, leaving only about a foot or so of each stem, or shoot. (A few thinner stems may be left to promote photosynthesis.) Wait a year and then select several of the healthiest looking shoots and branches. Leave those and cut everything else to the ground. The remaining growth can then be pruned to just above the buds, as desired. Keep in mind that it may take up to three years to have flowers again.
Although they are often used as landscape accent plants, lilacs can be used in hedgerows on property lines or in backyards along fences. They are also attractive when used as a shrub row along the outer edge of windbreaks.