Yes rosemary can sometimes raise your blood pressure.
If you already have high blood pressure then you should avoid using rosemary because the rosemary could cause your blood pressure to get to dangerously high levels.
Also if you suffer from other things such as ulcers, Crohn's disease, or ulcerative colitis then you should also avoid using rosemary because it can cause problems.
Pregnant woman should also avoid using rosemary during their pregnancy because it can lead to a miscarriage.
As long as you do not have high blood pressure then using rosemary is okay in moderation but keep check on your blood pressure to make sure it doesn't get too high.