Green Mountain Gardener

A visit to the UVM Hort. Farm proved to be well worth the trip, as lilacs are in their prime during the month of May.  Hundreds upon thousands of cobs of bloom dressed in shades of purple, pink, and rich cream were admired.  Walking down a path jam-packed with lilacs provides the senses with an overload of their lovely fragrance.  Lilacs are such a part of New England’s heritage that many believe them to be native, though the common lilac, Syringa vulgaris, originated in eastern Europe.  This species and hybrids of it were so frequently grown and selected by French nurserymen that France became synonymous with fine lilacs; we know them today as “French hybrids.” The term now commonly includes lilacs of that type even though they may not have been bred in France.  In 1767, Thomas Jefferson recorded his method of planting lilacs in his garden book, and on March 3, 1785, George Washington noted that he had transplanted existing lilacs in his garden. The oldest living lilacs in North America may be those at the Governor Wentworth estate in Portsmouth, N.H., believed to have been planted around 1750.

Lilacs grow best in full sun and well-drained soil. Lilacs grown in partial sun or shade will not flower well. The shrubs may take three to four years to establish themselves in a new site, but once established they can live for centuries. Soil pH (alkalinity or acidity of the soil) may affect the plant’s growth. Lilacs do well in a slightly acid to alkaline soil. New England soils are often very acidic and may require some modification for best lilac growth.

To ensure abundant flowering, cut off all spent blossoms each year and prune the flowering stem back to a set of leaves, thus preventing seed formation. If this is not done, good flowering years may be followed by bad years. Since flower buds are formed the summer before they bloom, it is best to prune right after flowering, preferably before the 1st of July.