An Old Fashioned Favorite
Lilacs are hardy and easy to grow in just about every zone. Most varieties do best in zones three through seven although there are also varieties that will do well in zones eight and nine. Lilacs generally grow as large shrubs. There are tree varieties that grow as small trees from a single trunk and dwarf varieties for those with smaller spaces in which to garden.
Lilacs have lovely heart-shaped leaves and blossoms ranging from deep red to white and even yellow. In most parts of North America, the flowers arrive in later spring, but here in the Rogue Valley (zone 7 or so), it’s earlier. They arrive in large clusters and have a short bloom period. Since their amazing fragrance is the most desirable quality of lilac, it would behoove Rogue Valley gardeners to plant several varieties – either from the nursery, from catalogs or from cuttings – that bloom at different times.
When planting, the choice of location is important and a decision to be made carefully. Lilacs resent being transplanted. They may root easily, but they tend to go sulky and refuse to bloom for several years after being dug up and moved. Lilacs require a minimum of four hours of full sun, but for the best blooms and disease-resistance, six hours is better. They like rich but sandy soil that is slightly alkaline and well-drained. Lilacs hate wet feet! If your drainage is wonky, lilacs will likely fail to grow and thrive. Proper planting, nutrients, ample water and a lack of stress will gain your garden fabulous foliage and fantastic blooms. No stress means no wet soil. All of the research I’ve done indicates that good drainage is absolutely key in keeping lilacs stress free. If your soil is too acidic, they won’t bloom well, if at all. Some varieties of lilacs can grow to 15 feet in height and quite wide, so be sure the spot you plant them will be big enough for their adult size. If you are planning on making a lilac hedge, be sure to plant them at least six feet apart.
Put your lilacs in the ground during a cool period in the year. Early spring is ideal; before they leaf out. Keep them watered while they get established. Too much nitrogen will cause your lilacs to have lots of leaves but few blooms. A little 5-10-10 organic fertilizer in the early spring is usually a good idea.
Powdery mildew is a fungal disease that makes the leaves appear as if they’d been dusted with white powder. While it’s unsightly, it doesn’t really affect the plant much at all. You can use one of the chemical fungicides if you must, or the good, old baking soda/water/soap blend that seems to work for everything, including roses.
Another issue with lilacs is the lilac borer. If your bushes seem to be wilting, look on the stems for tiny holes. You’re more likely to find this on older, woody stems. If you do find these holes, cut the stem off as close to the ground as you can get and burn the stem if you can. Whatever you do, get the stems off of your property. Taking the oldest of the stems off of your lilacs when pruning will help prevent an infestation of lilac borers.
Lilacs bloom on old wood. This year’s blooms will form on the stems that grew the year before. Too much pruning at the wrong time of the year will leave you with no blooms the following year. The main thing with lilacs is if you’re going to prune to do it IMMEDIATELY after the bloom fades. If the bush is large or overgrown, prune off the largest and oldest of the stems first. Look for the ones with woody bark. Unless your lilacs require major pruning to restore their shape and health, don’t remove more than 1/3 of the plant at a time. You can trim the tops back to a more manageable height, but you may not have as many blooms the following year. Shrub lilacs, the most common kind, will produce suckers from their root system. Remove suckers that are spreading too far out of their area. You can dig up the suckers and transplant them to start new shrubs. All lilacs benefit from deadheading so that they don’t form seeds. There is debate amongst gardeners about the need for deadheading. Deadheading will encourage more blooms, fuller growth of the bush and also keeps it tidier looking. It will also channel energy away from seed production and into the plant itself.
There are literally hundreds of lilac varieties. If you prefer the look of the old-fashioned lilac, the common lilac, Syringa vulgaris, is the ticket for you. Among the most popular varieties are Lilac Sunday (loads of fragrant blooms), President Lincoln (blue), Primrose (pale yellow), Krasavitsa Mosky (double flowers in pale pink), Sensation (violet/red with white edges), Charles Joly (double flowers of red/purple) and the late blooming James McFarlane. Of the dwarf varieties, the three most popular are the Red Pixie (burgundy red), Miss Kim (late blooming, traditional color) and Tinkerbelle (rose pink).
Lilacs are extremely long lived. There are lilacs in the Rogue Valley that have survived generations, giving their gardeners much joy and endless fragrance, both in the garden and in the home as cut flowers.