Tips for Growing Lilacs
Lilacs are one of those plants that people either love or hate. Gardeners have been growing lilacs for centuries, not only because of the show-stopping spring blooms but also for the flowers’ exquisite fragrance. Folks who hate lilacs think of them as just a weed, but those of us who disagree with that opinion know that growing lilacs is a labor of love. Lilac-haters just misunderstand these lovely plants.
Whenever someone tells me that they hate lilacs, their reason for this disdain is because they think all lilacs send out suckers, causing the plants to spread out of bounds. While it’s true that the ordinary, common lilac, Syringa vulgaris, does sucker, there are over a thousand varieties of lilacs these days and many of those varieties do not sucker.
Non-suckering lilacs will quite happily continue to grow for many years right where they were originally planted, without threatening to overwhelm neighboring plants. The creation of all these lilac varieties serves as a testament to the popularity of growing lilacs.
Lilac varieties are quite diverse and range from small shrubs that reach only four to eight feet tall, on up to tree lilacs that can grow up to thirty feet tall. Most lilac varieties are hardy in Growing Zones 2 through 7, because lilac plants originated in the cool, lower mountains of Asia. But even those in warmer climates can be growing lilacs these days because there are a few varieties that will bloom in Growing Zones 8 and 9.
Warm-climate lilacs are mainly in the hyacinthiflora and oblate families and they are typically early bloomers, producing their flowers in the cool spring weather. In Zones 8 and 9, you can be growing lilacs called Anabel which produces pink flowers, or enjoying the fuchsia blooms of Pocahontas lilac, or the white flowers of Sierra Snow. In Zones 4-8 you might also look for the cut-leaf lilac, Syringa laciniata. This lilac generally grows up to 8 feet tall and blooms in late spring.
Other varieties that are suitable for growing lilacs in Zones 4-9 include Blue Skies which tolerates heat and humidity. Blue Skies produces highly fragrant lavender-blue blossoms.
Lavender Lady is a bit taller than Blue Skies and will bloom reliably in Zones 3-8, while Miss Kim is a bit shorter and is also a good selection for Zones 3-8.
Miss Kim is one of the more popular landscape lilacs these days. Also known as a Manchurian lilac, Miss Kim grows no more than nine feet tall and produces pink buds that open up to ice blue flowers in late spring. In the fall the foliage becomes an attractive dark red color. If you like growing lilacs but you have a small yard, the compact Miss Kim lilac would be a good choice.
Most folks enjoy growing lilacs for their beautiful flowers, but the plants bloom for only a couple weeks each year. To enjoy lilac blooms for even longer, plant several varieties with different bloom times. Charles Joly produces it’s deep purple double blooms fairly early in the season, while Chinese or Japanese tree lilacs bloom about two weeks later. One of my favorite lilacs, James MacFarlane, produces its flowery-scented pink blooms in early to mid-June.
James MacFarlane is a beautiful lilac variety with an unusual scent. This variety does not sucker and it’s a fast grower, quickly reaching its typical height of eight feet, and this lilac will often begin blooming the very next spring after it is planted. Swallowtail butterflies seem to be particularly attracted to James MacFarlane blossoms, another good reason for growing these lilacs.
While most lilacs bloom in shades of lavender, pink or white, there are also yellow-blooming cultivars available now. Primrose is a yellow lilac that is hardy in Zones 3-7. For a real standout in your garden, add a yellow Primrose lilac to your collection.
Growing lilacs doesn’t come without a few pitfalls, and the most common problem is powdery mildew. Powdery mildew often occurs in hot, humid weather and it causes the leaves to develop a dusty white coating. Powdery mildew is unsightly but it rarely causes serious harm to lilacs.
The foliage can be sprayed with a fungicide two or three times a week to treat powdery mildew, or it can be prevented with a spray of potassium bicarbonate which can often be found at garden centers. Some varieties of lilacs are more resistant to powdery mildew than others, so if humidity is a problem in your area, consider growing lilacs that are powdery mildew-resistant, such as Miss Kim or James MacFarlane.
If a lilac bush isn’t blooming up to par, or not blooming at all, there are several possible reasons for the lack of blooms. It could be that the plant is not yet mature enough to bloom. Most varieties will not begin to bloom until after they have been planted for three or even four years. If you’re newly-planted lilac hasn’t bloomed yet, just give it some time to grow up and establish itself. A lilac that has been transplanted will often take a break for a year also before it resumes blooming.
Make sure your lilacs are growing in full sun. Lilacs bloom best in full sun and may not bloom well if they’re being shaded by taller plants.
If a lilac needs pruning, this should be done immediately after the plant has finished blooming for the season. Lilacs form new buds soon after the flowers die back, so if the plant is pruned later in the summer, over winter or in the early spring, those flower buds will be pruned off and there will be no flower show the following spring.
Growing lilacs is really quite easy, and by choosing the best variety for your yard, even the most ardent lilac haters can learn to love lilacs.