I don't know how it's possible but I'm a bit envious :)
My lilac died- the soil was just too sandy and dry for it and I'm not going to try again until I prepare a site for it, but I remember the wonderful smell of the one in our backyard when I was a child.
Two things that occur to me- one, I would think the variety of lilac might make a difference, and 2nd, perhaps the area where you have it- microclimate. No doubt, there are some real experts on here, so hopefully they will be able to help you answer that question. (One other thing- your local extension office- agriculture- probably has master gardeners available at certain times who could help- you might try that.) Brandy

Oooh, micro climates. I need to find out more about this to extend my growing capabilities.

But yeah, it is weird. Branches keep dying from this thing and I keep cutting those off. I need to move it. It's not very tall either. Maybe it's that dwarf lilac that I can't remember the name of.

It's also not impossible that this blooming one is a different lilac species from the others you have. "Lilac" as a word tends to cover a suite of species & hybrids from the genus Syringa. The one we tend to grow most is "common lilac" (Syringa vulgaris). There are also quite a few well known cultivated varieties of that species (Mr. Lincoln, Boule de Neige, Beauty of Moscow, Primrose, etc., etc.) However there are other species than S. vulgaris. One of the more famous of those is Korean lilac (Syringa meyeri).

In any case, congratulations!

How do I id it if it is Syringa meyeri? They all look the same to me.

Does it smell like a lilac?

That is neat! I don't know if it is a dwarf Korean one or a standard purple one, but it sure looks like a lilac to me.

My lilac needs to be cleaned out and tidied up. Should I prune it now or wait until fall? I was planning on severely pruning it.

To my nose the Korean smells distinctly differently - still "like a lilac" but nowhere near as sweet - more pungent somehow. It's also a smaller shrub and if I recall correctly I believe its leaves are smaller (but I'm not 100% on that).

I've never grown it and only seen it in person a few times, but that's what I recall.

I wonder if it is Korean. The flowers smell like lilac but more pungent. Very much like jasmine.

It's possible. Because it's more pungent, and definitely not as sweet, the adjective I usually use to describe the smell of a Korean lilac is "spicy", rather than "sweet" (which is definitely the word I'd use for common lilac, one of my all time favorite scents!!! :-))))

Personally I'm not a big fan of the odor of Korean lilac. I wish I was since it's a smaller bush and blooms later in the season, but - there ya go.........

aliska, the best time to prune a lilac is right after its flowers die. If you wait until autumn, you're bound to cut off some of next year's flowers, whereas if you prune right after flowering you won't sacrifice flowers because the buds you leave behind will have the whole season to develop flower buds if they can.

A variety of the Korean Lilac, I believe, is called 'Miss Kim'.