A Gardeners Forum Forums General Discussion The Plants and Flowers Forum lilac....berries?

Hello everyone,
it's been forever since i posted- happy to be back I have moved into a new house and with this house comes a ginormous lilac bush/tree- or at least, that's what i'm told it is. It's very very tall and wide and growing over my fence into my neighbor's yard. At the moment, it has these small dark purplish berries on it- which the birds love, which is great because it keeps my cat entertained from the window, but not so great because she wants to escape outside Before I forget to mention- the leaves looked incredibly unhappy and spotty before the weather got colder. Like there was mildew or some sort of disease issue.
So- leading to my question/questions: is it a lilac bush? If it is I never realized they grew berries.
Also, what is the best way to prune something that large and overgrown? It doesn't do much for the space of the yard- it grows over the sidewalk and i don't think the neighbors are in love with it. My dad thinks I can level it completely and it will still come back. I'd love a lilac bush (and i have one from the Arbor Day foundation- but it's still a very small stick- which I am fine with) but I don't want something that massive.
Any ideas on how to take care of this?

Thanks!

lilacs can have berries, so it may be a lilac bush. They can get quite large as well. The best time to prune a lilac is right after it blooms because if you wait until fall/winter, you will be cutting off many of next years blooms. However, if it simply must be pruned now, you'll get more blooms the year after next. BTW, you should never prune more than 1/3 of it's size.