Planar antenna with vertical polarization ?

Depends on the orientation of your PCB.

Vertical polarization means that a linearly-polarized antenna has the E-vector oriented vertically to ground. So if you already have such antenna on a PC board, set it so that the E-vector is normal to ground, and your antenna will radiate with vertical polarization.

You should be more specific on the orientation of the pcb material. Is the board lying flat on a table, or is it standing on edge upright?

I want to have my pcb horizontally planar (xy-plane), while I want to have vertical polarization (z-axis).