- Written by Robbi Hoy
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I can't imagine spring without the sweet smell of lilacs filling the air. Many of my childhood memories of spring involve picking lilacs and sharing them with friends and family.
Folklore tells us that lilacs were once associated with love. If you wanted to know if your secret crush felt as you did, you were to eat five lilac petals one after the other. If you could do this without one getting stuck in your throat, then your feelings were shared. It was also believed if a lilac limb was cut in late autumn and able to be forced to bloom by Christmas Day, an intended marriage would prove to be a good match. On the other hand, an old wive's tale says to bring lilacs in the house is sure to bring death upon it. This belief stems from the act of lining coffins with lilacs to reduce the odor. No matter if you are superstitious or not, most of us enjoy the bright blooms that lilac brings to us in the spring.
Here in Minnesota, lilacs can be seen lining the streets and alleyways from town to town. It is one of those plants that I can offer up to my southern friends who brag about what they can grow and I can't. I never fail to say "but I can grow beautiful lilacs!!" because although Syringa are great performers in northern gardens, hardiness zones 3-7 for most species, it struggles and rarely flowers reliably in southern gardens (Zone 8 and higher).
Common species of lilacs include the following:
- Syringa x chinensis: Chinese Lilac - Fragrant lilac purple flowers. 15 feet tall by 15 feet wide Zone 3-8
- Syringa meyeri: Meyer Lilac - Lightly fragrant bluish pink or lavender pink flowers. 6 feet tall by 4 feet wide. Zone 4 to 7
- Syringa persica: Persian Lilac- Fragrant purple flowers. 6 feet tall by 6 feet wide. Zone 3-7
- Syringa pubescens subsp microphylla: Littleleaf Lilac- Lilac-pink flowers. 20 feet tall by 20 feet wide. Zone 5-8
- Syringa reticulata: Japanese Tree Lilac- Fragrant, creamy white flowers. 30 feet tall and 20 feet wide. Zone 3-8
- Syringa villosa: Late Lilac- Fragrant pink flowers. 12 feet tall and wide. Zone 3-7
- Syringa vulgaris: Common Lilac- the most common form of lilac that comes in various colors and sizes depending on cultivar. Usually 22 feet tall and wide . Zone 4-8
Lilacs are very low maintenance and can survive a bit of abuse, especially Syringa vulgaris. They do best in fertile, humus rich, well drained, neutral to alkaline soil in full sun. For best results, mulch regularly and deadhead newly planted lilacs before fruits form. S. vulgaris tolerates hard renovation pruning very well. If planted in shady location, Lilacs will be afflicted with powdery mildew fungus yearly. Annual pruning of old flowers should be done as soon as flowers fade, to keep plants healthy and blooming profusely.
Pruning from University of Nebraska - Lincoln
To prune lilacs, cut out one-third of the oldest, woodiest stems as close to the ground as possible each year. This encourages the plant to generate new stems each year, and avoids the development of thick, heavy stems that are attractive to borers.
Unfortunately, as lilacs mature, the lower portions of the shrub become shaded and usually lose their leaves. As a result, large, overgrown specimens are often leggy and unattractive. Their thick, heavy stems are very attractive to lilac borers. Old, neglected lilacs can be renewed or rejuvenated by pruning. Home gardeners can choose between two different pruning methods.
The best way to rejuvenate old lilacs is to cut back the overgrown shrubs over a three-year period. Begin the procedure by removing one third of the large, old stems at ground level in late winter. The following year, again in late winter, prune out one half of the remaining old stems. Finally, remove all of the remaining old wood in late winter of the third year. Additional thinning of the new shoots should also be done if the new growth is too dense. Since lilac wood needs to be 3 or more years of age before it blooms, this pruning method should allow you to enjoy flowers every spring.
One way to renew an overgrown lilac is to cut the entire plant back to within 6-8 inches of the ground in late winter, March or early April. This severe pruning will induce a large number of shoots to develop during the following growing season. In late winter of the next year, select among last year's new shoots and retain several strong, healthy shoots to form the shrub framework. Remove all other shoots at ground level. Cut back the retained shoots to just above a bud; this encourages branching.
When properly pruned, an old, overgrown lilac can be transformed into a vigorous attractive shrub within a few years. Once rejuvenated, pruning should be a regular part of the maintenance program for lilacs. The shrub can be kept healthy and vigorous by removing a few of the oldest branches every 3-5 years.
Source: The American Horticultural Society A to Z Encyclopedia of Garden Plants and University of Nebraska - Lincoln