Sandalwood is a genus of trees renowned globally for their highly fragrant wood and the valuable essential oil extracted from it. The unique, lingering scent has made the heartwood one of the world’s most expensive timber commodities, driving its use in perfumes, cosmetics, and traditional medicine. Cultivating this slow-growing tree outside of its native range is complex due to its specific biological and environmental needs. Experimental growing operations are underway in the United States to meet the high demand for this luxury product.
Sandalwood Species Cultivated in the USA
The United States hosts cultivation efforts for several species within the Santalum genus, focusing on those with the highest commercial value. The most sought-after species is Santalum album, known as Indian sandalwood, which is prized for its superior oil quality and sweet, persistent aroma. This species is the most difficult to grow commercially on the US mainland due to its stringent environmental requirements.
The US territory of Hawaii is the native home to several unique species, including Santalum paniculatum and Santalum ellipticum, collectively known as ʻIliahi. These native Hawaiian sandalwoods are being cultivated and harvested sustainably to produce essential oil with a sweet and gentle aroma. They represent a viable, locally-adapted option for US production. Australian sandalwood, Santalum spicatum, is another species sometimes grown, offering a milder scent and stable source for the essential oil market.
Mapping the Ideal Climate and Growing Zones
Sandalwood is a tropical and subtropical tree that requires a specific, narrow range of conditions to thrive and produce its fragrant heartwood. The most restrictive requirement is a near-zero tolerance for frost, meaning optimal cultivation areas fall within USDA Plant Hardiness Zones 10 through 11. In these zones, minimum winter temperatures remain above 30°F (-1.1°C).
The tree requires a long, hot growing season with temperatures ranging from 54°F to 95°F (12°C to 35°C) to facilitate the development of the aromatic heartwood. This limits commercial feasibility primarily to the state of Hawaii, which naturally falls into the necessary tropical zones. On the US mainland, only the southern tips of certain states offer this required warmth.
The southernmost regions of Florida, particularly South Florida, and the coastal areas of Southern California provide the necessary conditions in Zone 10 and above. Experimental cultivation is also seen in microclimates of South Texas and Arizona, where high heat and long seasons compensate for the desert environment. Sandalwood prefers well-drained, sandy loam soils and a period of dry weather, making areas with distinct wet and dry seasons more suitable.
The Essential Role of Host Plants
The most complex horticultural requirement for sandalwood cultivation is its biological relationship with other plant species. Sandalwood is classified as an obligate root hemiparasite, meaning it must attach its specialized roots to a host plant to obtain essential nutrients and water for survival. Without this connection, a young sandalwood tree will struggle, exhibiting stunted growth and pale leaves, and will likely die.
The sandalwood tree forms a vascular connection with the host’s root system through a specialized structure called a haustorium. This mechanism allows the sandalwood to draw necessary nutrients, particularly nitrogen, phosphorus, and potassium, from the host plant. While the sandalwood tree is capable of photosynthesis, it relies on the host for this nutrient and water subsidy.
Successful cultivation requires the careful selection and planting of suitable, long-term host species alongside the young sandalwood tree. Fast-growing, nitrogen-fixing species are particularly effective hosts, such as certain varieties of Acacia and Casuarina. The host plant must be strategically planted close to the sandalwood, typically within six feet, to ensure the root connection can be established and maintained as both trees mature.