Can I combine St. Johns Wort tea and Rhodiola Rosea?

Not advisable. St John's Wort is a flowering plant of the species Hypericum perforatum. It contains a substance that acts like an SSRI, similar to Prozac or Zoloft (sertraline). SJW has the same problems that all herbal or "natural" compounds have - the concentration of the active ingredient is unknown, and such compounds are often heavily contaminated with aspirin-like compounds, or worse (e.g., heavy metals).