My rock garden has flowers which bloom in the spring (creeping phlox, peonies, columbine, iris), summer (lavender, hostas, marigolds) and fall (sedum). In the winter, some low lying evergreen gives the garden its interest.
English Lavender (Lavandula angustifolia) is beautifully fragrant; think English country garden aromatic. Both flowers and spikey leaves have essential oils. I frequently use the lavender in potpourri.
A perennial, lavender prefers dry conditions. It is a very compact plant. I have two clumps which have remain fairly static in size for 12 years.
Grade: A+ Lavender does well in Ohio's hot Zone 5 summers.