Encouraging adoption of Google+ (whether for internal or external use) has been tricky because it was the responsibility of the user to create their own profile. With a recent update to the Google Apps Admin Console, Administrators have the ability to create Google+ profiles for their users.
As of right now, this is only available on an individual basis, with hopes of bulk actions being added in the near future. Either way, this can make the process of rolling out Google+ even easier if the Admin has the power to create profiles.
This update is also only available for Premier, Gov and higher-education EDU domains only, so K-12 EDUs will not have access to this in the Admin Console.