| Try lavender, it thrives on heat and can be grown in pots, tubs and windowboxes. If you have room for a small tree (in a pot) there is one called Buddha's Hand citrus which is like a hand-shaped lemon that is very aromatic. I plan to get one soon. Jasmine may also work well for you, it seems to grow vigourously here in Sydney in sunny places. Marigolds and nasturtiums are also very easy and colourful. Likewise geraniums - and there are some geraniums with lemon-scented leaves I think. | 
