Culture
Grow in average, medium moisture, well-drained soils in full sun. Winter hardy to USDA Zones 9b-11. Plants are generally intolerant of frost. Best growth occurs in climates where nighttime winter temperatures do not dip below 45 degrees F., but plants will generally survive a few brief dips to 25 degrees F. albeit with some damage. Propagate by cuttings or seed.
Noteworthy Characteristics
Lagunaria patersonii, known by a wide number of common names including Norfolk Island hibiscus, primrose tree and cow itch tree, is a fast-growing, evergreen tree with a slender pyramidal habit that typically grows to 20-30’ occasionally maturing to 50’ tall with a spread to 10-20’ wide. It is native to Australia, principally being found on Lord Howe Island, Norfolk Island, parts of coastal Queensland and parts of north eastern New South Wales. It is cultivated as an ornamental for streets and parks in California, Florida and Hawaii. Australian island populations are usually classified as subsp. patersonia and the mainland populations are usually classified as subsp. bracteata.
Leathery oval leaves (to 4” long) are olive green above and gray-green beneath. Hibiscus-like flowers (to 2” across) are pink fading to white with petals encircling a conspicuous column of projecting stamens featuring showy gold to orange anthers. Flowers bloom summer to fall. Flowers are followed by pendant fuzzy brown capsules which release kidney-shaped seeds when ripe. Seeds are enclosed by fine hairs which can cause skin irritation to humans, hence the common name of cow itch tree.
Genus name honors Andrea Laguna (1494-1560), Spanish botanist.
Specific epithet honors Colonel William Paterson (1755-1810), Scottish soldier who was first sent to Australia in 1791, pursued interests in botany and exploration, and became Lieutenant Governor of New South Wales in the early 1800s. He reportedly first sent seeds of this tree to England.
Problems
No serious insect or disease problems. Susceptible to root rot.
Uses
Best for streets and parks in frost-free climates.