Above is a partial view of my test garden filtering through the webbing of a window screen. It's fascinating that only my camera lens would pick up the visual barrier because my brain doesn't see the screen at all. This idyllic image is the first thing that my wife sees each morning when she opens the bedroom window shades. At this time of the year, here in USDA Zone 4, perennials are still emerging and therefore, not very noticeable from far. What I like best about the above view is the fact it is framed in the foreground by the newly opened lilacs.
As the early species tulips are just about to mature and fade, this reliable, aromatic, flowering shrub is the next most exciting gardening event that we experience. The opening of its buds always precedes Mother’s Day by one week. That timing prompted me to create a family ritual. Every year on that special day, I harvest flowering branches and deliver them to my mother-in-law.
I am thankful to the original homeowners who chose to plant lilacs under the bedroom window. They intended that these shrubs grow tall enough to be seen from indoors and fill the room with sweet aroma. Ironically, here in Zone 4, spring is too cold to permit us to keep the windows open and our lilacs’ aroma does not enchant us into sleep. Instead, we cut a few branches and place them in water indoors. Then, the entire house is filled with lilac perfume, and we imagine that we have been transported to the fantasy of Shangra-la.
In the photo above, the white shrub to the left produces an intense sweet perfume. The pale rose-mauve shrub on the right, which I suspect is a very common variety, produces a too-mild aroma. Unseen in the photo, but to the right, is a purplish-wine bush emitting a deep, rich scent that is so intoxicating that it causes goose bumps to appear on my arms.
Gardeners who intend to plant lilac shrubs should keep in mind that at least six hours of sun is essential, full sun is best, and that many varieties will develop into a wide grove, so that it’s wise to allocate space for them to grow exponentially. Not all lilacs are alike; therefore, a plant may not bloom exactly when or how the gardener imagined that it would. That is why it’s a good idea to research online the habit of several varieties, and to carefully read the plant tags at the nurseries. Also, some plants perform bigger and better in climates warmer than mine. Local nurseries can be helpful in guiding gardeners in that regard.
French varieties are leggy and barren at their bottoms with a wide expanse at their tops; the Prestonia may be denser and more columnar in shape. The dwarf varieties, such as Meyeri Palabin, Kim, or Sugar Plum Fairy, grow into large round spheres measuring between three to four feet in diameter in my growing zone, and larger in warmer locations. Some nurseries offer them transformed into a costlier tree. That is done by grafting the miniature shrub onto a slender tree trunk to create a large lollipop-shaped plant. As a shrub or a tree, the pungent, spicy aroma of the dwarf varieties defies description.
Some varieties are miniature, short, medium, or tall. Bloom time may be early or later. Syringia Bloomerang and S. Josée, bloom in spring, and again later in the season, but I have not yet tested them. Some lilac shrubs are more fragrant than others are, and the nuances in the available color choices are excessive. Due to the large number of lilac varieties, controlling for specific characteristics often makes the selection more challenging than is necessary.
However, the most important advice about this shrub is that gardeners in cold climates should not attempt to control its height or shape. Although it is impossible to discern at first glance, lilacs set next year’s flowering buds on the branch tips of this year’s growth. In colder climates, with a shorter growing season, any attempt to trim the shrub will remove these buds and eliminate next year’s flower display. Some of us wait all year long to feel on high when we inhale a lilac's sweet aroma. Therefore, to avoid deep disappointment, this shrub should remain unclipped. For those in warmer climates, this issue may not be a problem. Please read what Carolyn reports in the comment section below.