It seems like everywhere you look these days, lilacs are in full bloom, filling the air with that unmistakable sweet scent. It’s no wonder so many gardeners want to bring these lush, dark-green shrubs into their own backyards. One of the biggest perks of growing lilacs? They are incredibly tough—and most of that “invincible” nature comes down to their powerhouse root systems.
Lilac Root Systems: Shallow or Deep?
If you’re wondering whether the common lilac is a shallow-rooted or deep-rooted plant, the answer isn’t exactly black and white. In reality, lilacs tend to spread their roots out in a wide, fan-like pattern just beneath the soil surface. You’ve probably even noticed a few roots popping up above the ground near the base of the shrub. However, they are also perfectly capable of digging deep.
A lot of this depends on your specific soil conditions and location. Lilacs are famous for being adaptable and will thrive even when conditions aren’t perfect. Depending on how much water and nutrients are available in the upper layers of your soil, the plant will decide just how deep it needs to go to find what it needs.
Generally speaking, a plant only works as hard as it has to. Deep roots are the “straws” that reach down for water and nutrients, while the shallow roots are responsible for sending out suckers and helping the plant propagate. So, technically, a lilac can be both a shallow and deep rooter depending on its environment.
What to Keep in Mind Before You Plant
Because lilac roots can be quite aggressive and spread far and wide, you really need to plan ahead. Keep an eye on nearby flower beds or stone walls that might get crowded out. If you’re dreaming of a lilac hedge, getting the spacing right is key. A good rule of thumb is to leave about 5 to 6 feet between plants to give them breathing room, though you can tighten that gap slightly for a denser hedge.
The fact that lilacs send out so many root suckers makes them super easy to propagate if you want more plants. On the flip side, it makes them a real pain to remove completely. Since the roots grow both deep and wide, getting rid of a lilac is a bit of a workout. If you ever decide to dig one out for good, you’ll need to make sure you remove the entire root ball and every stray runner, or it’ll likely find its way back!
