Many species of lavender will grow in partial shade and exhibit moderate shade tolerance, but vigor and full blooms are hard to come by in such conditions. If you want strong plants and a heavy aroma from your lavender, you should plant it in a location with full sun and little or no shade. Some species of lavender are more shade tolerant, while others will have a harder time growing at all in low light.
English lavender (Lavandula angustifolia) thrives best in full sun and well-drained soil, but it is somewhat shade tolerant and will still grow under low light. Under optimal conditions, it can reach a height of 20 inches and a width of 24 inches. In shade, it is less likely to achieve full size, though a limited amount of shade is still acceptable for growth. Do not overwater shaded lavender plants, and make sure the soil can drain to avoid root rot. The potpourri-like scent of English lavender is weaker in low light and moist conditions.
Other Shade-Tolerant Species
Some varieties of lavender exhibit moderate to minimal shade tolerance but will not grow vigorously without mostly sunny exposure. These include French lavender (Lavandula dentata), French lace lavender (Lavandula multifida) and Spanish lavender (Lavandula stoechas). These species grow best under full sun or sun with some clouds, but extreme shade can be detrimental to their growth and flowering.
Growing Lavender in Shade
If you insist on growing lavender in the shade, it will probably be somewhat stunted in growth and will not produce as many fragrant blooms. A spot with some dappled shade will be better than full shade. If you find no light is getting to the plant at all, it may be a good idea to transplant it to a sunnier spot. One of the problems with growing lavender in shade is the risk of root rot. Without lots of sun, soil has trouble drying and this disease can affect the plant. Provide quick-draining soil, water only in the morning and allow plenty of space between plants to prevent this problem.
Most species of lavender will grow in partial shade, but Lavandula latifolia, "Spike Lavender," is an exception. It should be planted in a location with full sun exposure and well-drained soil. It may not grow at all if planted in the shade. But it has highly scented flowers and, like all species of lavender, a shady spot is best for drying the flowers once they are cut from the plant.