The Shulhan Aruch (Orah Haim 217:1) rules that if one walks into a perfumery one should recite the blessing “Bore Mine Besamim”. On the other hand, a blessing at a florist would not be warranted since the purpose of a florist is not to be a purveyor of fragrances and rather that the flowers happen to give off a pleasant smell. Nevertheless, the Mishna Berura (O.H. 217:1) writes that if one takes a bouquet in one’s hand, one can recite a blessing before smelling it. The Hazon Ish disagrees with the Mishna Berura and writes that flowers are not grown specifically for their fragrance and thus one would not recite a blessing. Rabbis Ben Zion Abba Shaul, Ovadia Yosef and other Poskim, however, do side with the Mishna Berura, and therefore practically speaking one would be able to recite a blessing. Additionally, one is permitted to recite a blessing when taking a Nana mint tea bag in one’s hand to smell, so long as the scent is from the actual mint leaves and not from added fragrances. As well, one may recite “Hanoten Re’ah Tov Baperot” over a lemon, even though its primary function is a food and not a fragrance. Similarly, one would recite “Hanoten Re’ah Tov Baperot” over coffee beans, grounds or even instant coffee when taking them in one’s hand to smell, but no blessing is recited when entering a coffee shop which smells of coffee.
There is a discussion among the Moroccan Poskim regarding the blessing over lemon tree leaves. Rabbi Shlomo HaKohen (Veye’esof Shlomo, Orah Haim, § 24) says that even though there are opinions which state that the primary role of the leaves is to protect the fruit and not for fragrance, nevertheless one may recite a blessing, namely “Bore Atze Besamim”. He compares the leaves to cinnamon, which is not the actual fruit of the plant but rather the inner bark, but nevertheless warrants a blessing. Furthermore, the HIDA (Mahzik Beracha) writes that one may even recite a blessing on the peel of fruit.
Rabbi Makhlouf Abuhatzira (Yefe Sha’a, § 10) responds to a question regarding the practice in Beni Mellal, Morocco, of reciting a blessing over lemon leaves during a Brit Mila. On one hand he explains that it is not so clear that one may recite any blessing before smelling these leaves since they are not the fruit of the lemon tree. Nevertheless, he concludes that since it is an established custom in that city, there are sufficient grounds to uphold this practice.
Summary: The blessing when entering a perfume store is “Mine Besamim”. The blessing over lemons, fruit peels, coffee beans or grounds is “Hanoten Re’ah Tov Baperot”. The blessing over lemon tee leaves is “Atze Besamim”.