Sandhill Rosemary

Description:

Sandhill rosemary is a perennial, aromatic shrub with a fragrance resembling rosemary. The species grows to approximately 2 to 2.5 meters in height with dense, multi-branched, grayish, twigs that are covered with short, gray, tomentose (wooly) hairs. The needle-like evergreen leaves are 8 to 15 mm in length by less than 1 mm in width. Leaf margins are revolute and the leaves are arranged in whorls of 4 or 6. This arrangement exhibits a square like or hexagonal shape when viewed from above (see left, above image). Plants are sexually mature at 10 to 15 years or age, with peak seed production between 20 and 30 years or age. Sandhill rosemary produces flowers from March to June and sporadically in other months especially after long rain events. The plants are dioecious meaning individual plants are either male or female. Flowers of both sexes are composed of persistent yellowish to reddish sepals and petals. Sepals and petals are normally 2 in number and are approximately 1.5 mm in length with two stamens (male plants) or two styles (female plants) which are long and protrude from the flowers. Both sexes have flowers borne from the leaf axils. The fruit, produced from June through August, is yellow or pinkish-red and 2 to 3 mm in diameter (Patrick et. al. 1995).

All sandhill rosemary plants that are burned will die, but patchy fires that are typical in many habitats may leave patches of surviving plants. Salt-spray and storms may induce mortality in coastal habitats. Sandhill rosemary populations have exhibited a slow recovery after fire with slightly increasing local abundance for the first decade. Thinning of the populations due to resource competition occurs between 10 to 20 years of age. Plants may lose productivity and begin partial dieback after 20 years, but some plants can survive in excess of 50 years. Although 50 year old individuals have been found, after age 35 large branches may rest on the ground and successfully root as the rest of the plant dies back, making aging of older individuals difficult). Uneven-aged inland stands are typically dominated by a single cohort or a few cohorts, whereas coastal populations are all-aged (Wally and Menges 2002).

Habitat:

Sandhill rosemary inhabits the driest, openly vegetated, scrub oak sandhills and river dunes containing deep white sands of the Kershaw soil series. Woody goldenrod (Chrysoma pauciflosculosa) and extensive mats of lichens are common associates (Patrick et. al. 1995).

Range:

Sandhill rosemary is found on the Coastal Plain from Mississippi to South Carolina, found mostly on coastal dunes, but also inland on the Florida Peninsula, river dunes and sand ridges in southeastern Georgia, and on sandhills along the Fall Line in eastcentral Georgia and South Carolina (Wally and Menges, 2002).