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Growing lilacs

Lilacs are an elegant, low-maintenance addition to any garden, providing endless fragrance, colour and drama

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Lilacs aren’t just for spring. There are new types on the market that can bloom intermittently over the summer and into fall. Photo: Proven Winners

Fragrances can spark memories of long ago. For me, the smell of lilacs brings back the memory of my high-school graduation. The stage was lined with huge bouquets and the fragrance drifted throughout the entire gymnasium. Every year when lilacs bloom and I catch the first whiff of their delicate scent, I am transported back to being 17.

For other people, lilacs evoke memories of grandmother’s house, or of the springtimes of youth. Whether you have lilac-inspired memories or not, it is never too late to add this classic shrub to your garden.

The original Syringa vulgaris (common lilac) is a long-lived plant, lasting 200 years or more. You often see forgotten hedges of them in overgrown fields where they once attended a since vanished farmhouse. If you plant this species of lilac, be sure to choose a spot where people won’t disturb it.

Lilac blossoms form panicles of single and double flowers in colours ranging from white to light pink, medium pink, light purple/blue, light purple, medium purple and dark purple. Some have white edges.

While the fragrance hasn’t changed over the years, the lilacs certainly have. Instead of just two weeks of bloom, you can now plant a series of lilacs for early, mid and late blooming pleasure. There are even re-blooming lilacs on the market that give sporadic bloom over the summer and another full flush in early autumn. Along with the large, suckering shrubs of decades ago, there are now tidier dwarf varieties to choose from.

Bob Osborne, owner of Corn Hill Nursery in southeastern New Brunswick, is a fan of lilacs. “Each is unique and can be used in combination with other plants to create interesting tableaus,” says Osborne. His top lilac varities are: “Krasavitsa Moskvy”—a breathtaking double pink/white with very healthy foliage; “Ludwig Spaeth”—one of the best old, deep purples; and “Sensation”—a delicate lilac best viewed close up where you can appreciate its white edges.

If scent is your main priority, Osborne recommends the common vulgaris types. “Some of the hybrids such as “K. Moskvy” and the double white “Mme. Lemoine” are very fragrant,” he says. “Perhaps most intense is the dwarf lilac Syringa patula “Miss Kim.” It is still fragrant after the flowers wither.”

“Bloomerang” is a reliable re-bloomer, especially where summers are not too hot and humid, giving its best show in spring and fall.

Be sure to purchase your lilac shrub while it is in bloom to ensure you pick the colour you desire and to confirm that the shrub is old enough to produce blooms. Some lilacs take three to four years to begin blooming.

Keep in mind the mature size of the plant. The Syringa vulgaris grow to almost four metres high and over two metres wide at maturity. However, there are dwarf species and cultivars that grow to half that size. Lilacs also come in tree varieties, such as Syringa reticulate, that can reach seven metres tall.

Lilacs are a relatively low-maintenance species if you take care of their basic needs from the beginning. They will thrive in zones 3 to 8. Be sure to plant them in an area with full sun—six to eight hours a day—for the best bloom. Lilacs do not like excess moisture near their roots, so avoid planting them in a boggy spot or where they will suffer from water run-off.

If your soil is the typical Atlantic variety, add lime as lilacs like things a bit sweeter than most soils in our region. Osborne says they prefer nearly a neutral pH. Too much fertilizer will result in lush greenery but fewer blooms—keep this in mind if you plant your lilac on a fertilized lawn. A common problem of your grandmother’s lilac bush was powdery mildew but newer varieties have been developed to resist this.

Lilacs need regular annual pruning. As soon as the shrub finishes blooming, cut away the finished blooms, as well as any branches you wish to remove to shape the bush. Lilacs start forming next year’s blossoms soon after they finish blooming. If you wait until summer, fall or early next spring to prune, you will be cutting off the new blooms. This is called “blooming on old wood,” as opposed to “blooming on new wood” like hydrangeas.

If your bush is old or overgrown and needs rejuvenation, cut one third of the branches back to the ground. You can do this in summer or fall as you will be losing the bloom in any event. Do this again the following year with another third of the old growth. The third year, cut the last third of old growth to the ground. This way you won’t overstress your shrub. It will still obtain yearly bloom, and by the fourth year you will have a totally new, invigorated plant. You should prune re-blooming lilacs right after blooming, much like annual flowers.

Lilacs will form dense hedges and screens when grouped—their suckering habit makes this easy. But you can also use them in mixed shrub borders and in large perennial borders.

Remember, if you carefully select and plant your lilac, it will likely outlive you—another reminiscence to add to the fragrance memories.

Bloom times

Early May: Hyacinth lilac (Syringa hyacinthiflora); Early lilac (Syringa oblate)

Mid May: Common lilac (Syringa vulgaris); Persian lilac (Syringa persica); Chinese lilac (Syringa chinesis)

Late May to Early June: Preston lilac (Syringa prestoniae); Komarov’s lilac (Syringa komarowii); Josee lilac (Syringa Josiflexa)

Late June: Japanese tree lilac (Syringa reticulate); Peking lilac (Syringa pekinensis)

“Still grows the vivacious lilac a generation after the door and lintel and the sill are gone, unfolding its sweet-scented flowers each spring, to be plucked by the musing traveller; planted and tended once by children’s hands, in front-yard plots, now standing by wall-sides in retired pastures, and giving place to new-rising forests; the last of that stirp, sole survivor of that family.” —Henry David Thoreau
East Coast Living