This adaptable lavender stands out because of its habit: It grows in a decidedly rounded mound and produces large spikes of dark purple-blue flowers in late spring and early summer. 'Betty's Blue' is a compact variety that shines when grown as a small hedge or in a knot garden. Name: Lavandula angustifolia 'Betty's Blue' Size: To 30 inches tall, 36 inches wide Zones: 5-8