I don’t think there is evidence of any consistent effect of cannabis on blood pressure outside of the effects that accompany relaxation or excitement, and those have little to do with the chronic kind of high blood pressure treated with medications. Insofar as you can select strains of cannabis that tend to relax or excite you I suggest a bit of cautious experimentation, following the advice usually given that “indica” effects tend to be relaxing and “sativa” effects tend to be activating. Throw in terpene effects and the way most strains of cannabis are now extensively hybridized, along with the variability of people’s reaction to cannabis, and you can see why there is no simple answer to your question. If you are already being treated for hypertension I would not rely on cannabis replacing your medical treatment. If you do want to decrease your medication use while using cannabis I’d recommend doing it under your physician’s care and not on your own.