Yes it is very possible to get high off of smoking the rosemary leaves.
When you dry the rosemary leaves and then smoke them in either a bong or make them into a cigarette and you smoke the rosemary you should be prepared to get high.
I would not recommend smoking the rosemary though because it could be harmful to your health but if you want too then just be aware that you will likely become high off of smoking the rosemary and won't know what's going on.
That is until the high from the rosemary being smoked eventually wears off.