Take a walk outside lately and you may notice the air is thick with the fragrance of Japanese tree lilacs in bloom. The trees’ sweet, heady scent might grab your attention even before the large clusters of creamy white flowers that cover their branches do.
A popular choice in recent years for planting in parks, residential areas and along city parkways, the Japanese tree lilac is prized for its showy spring flowers, as well as its ability to adapt to somewhat challenging sites. Trees tolerate soil conditions ranging from acid to alkaline, and even salty, making them an ideal choice for planting along roadways where salt spray is common in winter.
Native to northern Japan, Japanese tree lilacs reach 20 to 30 feet in height, with a spread of 15 to 25 feet, and mature into a graceful, rounded shape. The aforementioned flowers bloom in 6- to 12-inch clusters at the ends of branches for a week or two in early summer and are followed by capsules of winged seeds that are scattered by wind – if the songbirds don’t get them first.
Trees are hardy from zones 3 to 7, which means they can withstand our cold northern Illinois winters. They are susceptible to very few diseases and require little in the way of pruning. Simply remove damaged branches and twigs as needed.
Japanese tree lilacs thrive when sited in full sun (at least six hours of direct sunlight per day) and moist, well-drained soil. They are attractive when planted singly as specimens or in a group. These prolific bloomers are easy to transplant, and readily available at most nurseries and garden centers.
And since Japanese tree lilacs flower after the blooms have faded on most shrub lilacs, but before many of the summer blooming perennials really burst into color, they are a nice way to fill in the gap. Once flowering has ended for the season, the deep green leaves and glossy reddish-brown bark make the trees an appealing part of the landscape.
To establish a healthy root system, water Japanese tree lilacs regularly throughout their first growing season, and always remember to water in periods of drought or extreme heat.
Trees can be fertilized in early spring, and any necessary pruning can be done before new growth begins as well. These trees have a life expectancy of 40 to 50 years, though their life span may be shortened if planted in an urban landscape.
Sarah Marcheschi is a University of Illinois Extension master gardener for Kane County. The “Learning to Grow” column runs weekly during warmer months of the year. Call the extension office at 630-584-6166 for more information. Feedback on this column can be sent to firstname.lastname@example.org.