'Prostratus' spills down retaining walls in this Southern California garden; DESIGN: Carole McElwee
'Prostratus', 2 feet tall and 4 to 8 feet wide. Pale blue flowers. Most commonly used rosemary for cascading down walls, as in the photo at left of the garden designed by Carole McElwee of Capistrano Beach, California. Fairly frost tender.
'Irene', 1 1/2 feet tall; spreads 2 to 3 feet per year. More hummocky form than 'Prostratus' or 'Huntington Carpet' (see below). Showy violet blue flowers. Good choice for draping slopes or walls. Hardier (to 15°) than most trailing types.
'Huntington Carpet' ('Huntington Blue'). About half as tall and wide as 'Prostratus' (above). Leaf nodes are closer, so the ground cover has a denser appearance. Pale blue flowers. Excellent choice for covering slopes or trailing down walls.
BEST KINDS FOR COLD OR WET CLIMATES
'Arp', 4 feet tall and wide. Rather open habit but can be kept denser with frequent pruning. Gray green leaves; bright blue flowers. Hardy to -10°.
'Hill Hardy' ('Madalene Hill'), 3 to 5 feet tall and as wide. Foliage denser and brighter green than 'Arp'. Hardy to at least 0°.
'Salem', 2 feet tall and wide. Fairly tolerant of wet soil, it's a popular choice in moist areas of the Pacific Northwest.
BEST CULINARY KINDS
You can use any R. officinalis for cooking, but upright kinds with broader leaves contain more aromatic oil. 'Tuscan Blue' is the favorite of many chefs, but 'Blue Spires' and 'Miss Jessup's Upright' are also good. So is 'Spice Island', which is normally sold in the herb section; it grows into an upright, 4- to 5-foot-tall shrub.
Garden centers and nurseries may carry only a few kinds of rosemary, but most can usually order other varieties from wholesale growers on request. Or order plants from the following mail-order suppliers.
Forestfarm: www.forestfarm.com or (541) 846-7269. Sells 'Arp', 'Blue Spires', 'Golden Rain', 'Spice Island', and 'Tuscan Blue'.
Goodwin Creek Gardens: www.goodwincreekgardens.com (800) 846-7359. Sells 'Arp', 'Blue Spires', 'Collingwood Ingram', 'Golden Rain', 'Gorizia', 'Hill Hardy', 'Miss Jessup's Upright', 'Prostratus', and 'Tuscan Blue'.
Mountain Valley Growers: www.mountainvalleygrowers.com or (559) 338-2775. Sells 'Arp,' 'Golden Rain', 'Hill Hardy', and 'Spice Island'.
Territorial Seed Company: www.territorialseed.com or (541) 942-9547. Sells 'Arp' and 'Salem'.