Fragrance is subjective, so experiment with herbs. Hot summers are ideal for annual basil (Ocimum basilicum), which smells as good as it tastes. Grow several plants, and run your hand through the leaves to release their aroma. Do the same with rosemary (Rosmarinus officinalis), an herb that's evergreen in Zones 7-10. In colder climates, grow it in a pot and take it indoors over the winter. Lemon verbena (Aloysia triphylla) is another fine candidate. Grow it in a roomy pot that you can move into a garage or other protected place during hard freezes. Try a few scented geraniums (Pelargonium selections) too; they come in scents from citrus to rose and make attractive houseplants. Humidity is a problem for English lavender (Lavandula angustifolia), so if your climate is damp, a better choice would be Spanish lavender (L. stoechas).