One plant I'm sure you are probably aware of is lilacs....fragrance second to none, with an added benefit being that the flowers can be cut and brought indoors for vase arrangements....a sure sign that spring has arrived. Another you may want to pick up is the Osmanthus fragrans. This is an evergreen shrub with tiny white flowers with an enjoyable floral aroma, but one a bit more subtle, yet definitely a pleasing smell you can not miss. Best of all, its flowering period is late spring into mid summer after the lilacs are finished, giving you much more time to enjoy the wonders of your garden.