What kink of shrub? How large is the shrub? What kind of clematis do you have?

I have two...Ville de Lyon and Duchess of Albany for Clematis. I have a Cornus racemosa that is plain all season long, about 8ft tall. Or I have a few Hydrangeas, a Viburnum maresii, or a Physocarpus. All of those are under 5ft at this point.

I have a Ville de Lyon growing through an Endless Summer hydrangea and from there onto the fence behind it. I have another type 3, white, but I don't remember the exact hybrid, up into a lilac. In each case I planted the clematis on the north side of the shrub, outside of the shrub's dripline by about a foot. I had read that the clematis would grow toward the light and therefore into the shrubs. It seems to have worked well as the Ville de Lyon has been there 3 or 4 seasons and the white one two or three. The lilac looked like it had white clematis flowers this year for the first time, and VdeL has been growing up into the hydrangea for several seasons. The shrubs were a year or two in the ground and at least three feet tall when I planted the clematis which were pretty small. I may need to move the VdeL at some point if it seems like the hydrangea is getting overwhelmed.