One of the most beautiful, fragrant, and easy to grow shrubs in the garden is the Lilac and its many cultivars. As common as they are, they are not native to this country; the first lilacs were probably brought to New England from Europe in the 1620s. Two species, Syringa vulgaris (the Common Lilac) and S. josikea, are native to Eastern Europe, while the rest come from Asia.
Several species of Lilac can be planted together to create a multi-seasonal bloom, stretching from May (S. vulgaris and cultivars) through July (the Tree Lilacs,S. pekinensis and S. reticulata). The Chinese Lilacs (such as the smaller variety ‘Miss Kim’) boast beautiful purple fall foliage, a striking contrast to the typical yellow and yellow-brown.
Flower color ranges from pure white and cream, to varying shades of pink, lavender, and purple. Fragrance can be almost non-existant, as with the Tree Lilacs, to the heavy, heady, famous ‘lilac’ fragrance of the French Hybrids.
All Lilacs should be planted in well-drained, non-acidic soil, in a place where they will get at least 6 hours of sun, and excellent air circulation. Good air circulation is critical in the prevention of most disease and pest problems (for all plants, not just lilacs).
Lilacs, for the most part, are blessedly free of pests and major diseases. Powdery mildew can be a cosmetic problem in the later months of the year; it rarely is anything more than unsightly. Lilac Bacterial Blight is a slightly more serious disease, characterized by brown leaf spots and rapid browning of young shoots. This disease is rarely fatal to the plant as long as the affected stems pruned and destroyed. There are occasionally caterpillars or leaf miners that find reason to munch on the foliage, but again are rarely an issue.
To rejuvenate overgrown or declining lilacs, cut one-third of the largest trunks to the ground each year to encourage the growth of new shoots from the base. Over a three-year period, the lilacs will rejuvenate without a complete loss of bloom or canopy. Pruning in early spring when leaves are absent will make it easier to see which stems need to be removed.
And now, the question that is asked most frequently in regards to Lilacs:
Why isn’t my lilac blooming??
Some lilacs begin to bloom within two years of planting, while others take five years. Heavy blooms normally occur only every other year as with many woody flowering plants. The following tips can help ensure that you get the biggest bloom for your buck out of your lilac:
- Plant lilacs in full sun. Lilacs will never bloom well in the shade.
- Lilacs need well-drained soil and will not tolerate standing water.
- Prune lilacs immediately after blooms fade; buds for the following year are poduced in June and July.
- Overgrown lilacs with many thick, older branches and rampant suckers do not bloom as well as ones with a few well-maintained branches of younger ages.
- Lilacs rarely need fertilizer. High nitrogen fertilizers favor leaves over flowers and may increase winter injury and bacterial blight.
- Deadheading often improves flowering on young lilacs.
*Some information gathered from the University of Montana. Visit http://www.montana.edu/publications for more information on this and many other gardening topics.