"Notify" in what way?
People can choose to be notified1 by your posts (either you specifically or a Circle that they've put you in). But you're not in control; they are.
Elsewise, you can check a box to "also send email to {circlename}" which will do what it says, but a lot of people have been complaining about this feature being abused. (I've gotten my fair share of G+ spam from people I don't really care to hear from. It earned them a "blocked by Al" badge.)
Otherwise, no, you can't foist a notification on someone who would rather not be notified about your posts.2
1 In other words, get Mr. Jingles to alert them to the post in the Notifications panel.
2 Unless you use the trick you've already discovered of including them by name instead of the Circle you have them in.