36-40" tall x 36-40" tall. Rosemarinus Hill's Hardy (Hill’s Hardy Rosemary) is a cold hardy form of Rosemary. 'Hill's Hardy' is an irregular, upright growing variety that blooms in early to mid-spring with large, light blue flowers. The evergreen foliage is intensely aromatic and this selection is especially cold hardy for climates that dip below zero degrees in winter. The bees love the nectar-rich early spring flowers.