I seem to recall that lilacs are one of those plants that are cold-adapted. That is, they require a cold period to reset and come back better next year. If there’s no cold period, they don’t do well. (I think rhubarb’s another one of these - it won’t grow without a winter.) Personally, I’m rather glad that there’s some of these type plants - I’m tired of all the really pretty stuff only growing down south. At least they can’t have lilacs too.
And it’s lie-lacks for me.
They don’t grow in the South - well, that’s not true. They grow but don’t bloom. I have never smelled one.
Waiting for an expert to show up.
Anyone live in “the Lilac Village” - home to Lilacia Park and the annual Lilac Parade?
C’mon, dropzone - settle this one!
Well, I actually say it “lye-licks.” Between the two pronunciations in the OP, however, “lye-lacks” sounds more natural than “lye-locks.”
The last time someone gave me a lilac I smoked it.
LOL! 
I grew up in upstate NY where we called them Lie-Locks. It is the ONE thing that I miss about the nawth. They don’t grow here in Flawduh and I sure would love to put a big bouquet in a vase (pronounced like pace ) and have my whole house smell wonderful. I love them.
None of the above, for me.
It’s LIE-luhx, or in fact more like LIE-l’x, with a very short schwa vowel.
How else would you say vase? You mean how people pretend to be snooty and say “vaaazzz,” or is there some secret dumb Yankee way?
LOL This dumb yankee says vase/pace.
I love Lye-locks. I have three but only one blooms. I think the secret is a lot of sun.
Can’t wait for my Lily-of-the-Valley and Honeysuckle to bloom.
I use both lye-lock and lye-lacks interchangably – FWIW, my mother (a Northerner) always said lye-locks, while my father (most decidedly Southern) said lye-lacks.
Lily-of-the-valley smells positively divine. I don’t have enough sun for those, but I used to have an entire hill of them. It was a thing of beauty.
My Lily-of-the Valley grow in the shade of my lilac…which I pronounce lie-lack.
Lie-locks. Michigan and Minnesota influences.
Lie-locks
Heh, someone didn’t tell that to the ones in my front yard: they’re going freakin’ NUTS and have been since we’ve planted them! (We have a mix of lilac varieties.) Their blooms will be over soon though, they don’t last anywhere near as long as up North.
And I tend to waffle between pronouncing 'em ‘lie-lacks’ and ‘lie-locks’ depending on what other words are around them.
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What Colophon said. The second syllable isn’t emphasized and the ‘a’ is not pronounced like it is in ‘back’.
I thought* I* lived in the lilac (lie-lack) city! In Rochester, NY, where we have the annual lilac festival, most of us say lie-lack. I notice that some of the local news reporters say lie-lock.
lie-lacks. Never heard it pronounced any other way, certainly not “lie-locks”.
Me either. It’s always been “lie-lacks” in my part of the world.