The two common herb/spice brands are McCormick and Masterfoods,
available from most supermarkets, even Fairprice.
I've heard that one can make rosemary tea from dried rosemary but I
haven't tried it, as I only use it in cooking. I'm not sure about
using fresh leaves to make tea. Perhaps a search on the internet
may yield some info?
Re your last question, a herb such as mint - even if the leaves are
not harvested, they turn yellow, wilt and die, and afterwards the
whole plant (ie the stem) reaches maturity, dries up and die too -
that's the nature of a herb.
Some herbs need to be replanted from seeds, while others (e.g. my
catnip) is able to regerate new shoots/stems from the existing stem
before it dies.
