The scent of sweet alyssum (lobularia maritma) is as pretty as its name. Fortunately, it's also one of the easiest annuals to grow. Seeds can be sown uncovered directly in the ground as soon as it thaws or in pots, and the plants will bloom from early spring to fall in full sun to part shade.
Alyssum is a mat-forming plant with dense clusters of tiny, sweet-smelling flowers. With little effort and expense, this plant will give you the most fragrance in your garden for a minimum investment; although it's low to the ground, the intense scent floats through the air. It also grows easily from inexpensive seed and reseeds itself [source: Ferguson].