– Christine Gelley, Agriculture and Natural Resources Educator, Noble County OSU Extension
Lilacs are most often shades of purple but can also be white, pink, or nearly blue.
Lilacs are already actively blooming in Southeast Ohio! According to my records of lilac bloom times, they are a bit earlier than I’ve seen in the past three years or so. Lilac bloom time will forever be stamped in my memory for comparison because last year when we brought our baby Naomi home from the hospital, the lilacs were just starting to bloom along our deck. Their delightfully sweet fragrance wafted in through the windows while I held that precious newborn close and soaked up everything about spring. That was May 13, 2022. That memory is just one reason I love lilacs.
Lilacs are most often shades of purple (my favorite color), but can also be white, pink, or nearly blue. They often cross-pollinate with one another creating hybrid seed and spread easily by root suckers, giving planted areas a naturalized feel. There are many varieties and cultivars of lilacs available for purchase, but lilacs can also be found across the United States and Canada growing wild and free. The common lilac (Syringa vulgaris) was originally from Europe, but is now considered a naturalized species of North America. Hardy to -60°F, they have no trouble over wintering. Because they are fast growing, they can recover quickly from physical damage like cicada activity, ice, wind, excessive rain and drought.
These hardy shrubs are a fabulous option for people that lack a green thumb. They are quite tolerant of gardening neglect and abuse. They are not picky about soil conditions, rarely require fertilization, and have few pest or disease problems. They work well as border shrubs, privacy screens, vertical interest, and are highly attractive to pollinators.
The most common problem I seem to hear related to lilacs is that they are growing and spreading more than desired. The good news here is that lilacs are easy to prune, divide, and replant. If your lilacs are getting out of control, the best time to prune them is after they finish blooming.
Lilacs that are less than three years old usually do not require pruning. Wood that is older than four years is often removed in order to keep the plant looking more like a shrub than a tree. Prune older stems from the middle of the shrub to encourage new shoots to fill in evenly.
To keep tall growing lilacs from appearing leggy with growth and blooms at the top, but bare at the bottom, prune the oldest stems back (equivalent to about one third of the plant per year) until they reach the desired height for your landscape. To prevent tree-like lilacs, you can select other species, like little leaf lilac (Syringa microphylla) or Korean dwarf lilac (Syringa palebinina), which are bushy species, rarely exceeding five feet tall.
The best time to divide, replant, or share lilac root suckers is in the fall after the leaves have dropped, but before the ground freezes. This will encourage root growth before winter and help the young shrub to acclimate to the environment before winter. Spring division and replanting can be accomplished in spring, but the window of opportunity for success is shorter. Divide the root suckers from the mother plant before the flower buds begin to unfold. Otherwise, the plant will allocate energy to the flowers instead of to the roots.
To divide the root suckers, use a clean, sharp garden spade/knife, or pruners to cut the root connecting to the mother plant. Choose suckers that have healthy looking bark and lots of other roots developing. Replant these cuttings immediately or repot them in a moist soilless potting mix until you can plant them or share them.
On rare occasion, I have seen lilacs bloom in the fall. Out of season blooming occasionally occurs with flowering trees and shrubs after being subjected to an extended period of drought which induces dormancy and when conditions improve, triggers flowering. Much to my delight, it happened to my neighbor’s lilac last year, right across from our mailbox. I got to enjoy lilacs in bloom twice in 2022. Plants that flower out of season due to environmental stress may skip flowering or struggle in the following year. Just treat them like normal during the in-between time.
Overall, lilacs are a welcomed low-maintenance, flowering shrub, hardy to our area that I recommend for use in the landscape. If you want to learn more about lilacs, you can call your Extension Office or Cornell Cooperative Extension has a great fact sheet on the topic that can be accessed online at http://chemung.cce.cornell.edu/resources/lilacs.