Rats. They didn't say I needed a pollinator either. And it's in an extremely dry area.. very very very very very xeric. OK, another plant to be moved. I can put it elsewhere where it'd get a lot more moisture (which isn't saying anything.. it doesn't get ANY moisture there). And I desperately need to give that lilac a MAJOR haircut. It's huge, old (about 30 years old), and very top-heavy & leggy on the bottom.
Thanks everyone!!