Are you using powdered rooting hormones? They have a tendency to have a difficult time staying on the roots.
You may want to see if other members have better advice concerning root hormones. I personally think that if you're gonna use rooting hormones, that you get some quality lab hormones, and you apply it directly on the roots as a short soak.
I would not continually reapply rooting hormones, I don't know what kind of specific side effects it may have, but it may not help your cause if overdone.
You may get lab quality hormones at Phytotech Laboratories:
Home Page - PhytoTechnology
Being that I'm not really the hormone go-to-guy, you might want to ask around first as people may have differing points of views.