SQL Server 2012 AlwaysON Replica Backups

I am using SQL Server 2012 on Windows Server 2008 R2 Core.

I have alwayson configured and running.

I have transaction log backups set to run on the replica.

They are running successfully. 

I do NOT have any transaction log backups running on the primary server, only full backups 1x a day.

The transaction log on the primary is not truncating, just keeps getting bigger and bigger.

Is this by design?  If so, I MUST run transaction log backups on Primary, which negates the performance gain of just running them on the secondary replicas.

The question is...do I have to run tlogs on the primary even if I'm doing them on the secondary to keep the log file from growing out of control?

Thanks!  Ben Jongewaard