Beach naupaka invading seaside habitat on Virginia Key in Miami, Florida.
Beach naupaka is a robust bushy evergreen shrub to 10 ft (3.1 m) tall and about as wide. Its habit is a dense, multibranched mound of light green foliage. Branches root where they touch the ground. The leaves are 3-6 in (7.6-15.2 cm) long and crowded at the tips of the twigs. Beach naupaka is sometimes called half-flower because the flowers have petals on just one side, like a hand fan. The five petals are white to pale violet. It blooms most of the year with a peak in summer. The mature fruits are fleshy white drupes about 0.5 in (1.3 cm) long. Beach naupaka is similar to the native herbaceous shrub, inkberry or beachberry (Scaevola plumieri), which is listed as a Threatened Species by the State of Florida. The native species is smaller and less woody, has more succulent leaves that are just 1-3 in (2.5-7.6 cm) long and has black fruits.
Beach naupaka occurs naturally on beaches and atolls throughout the tropical Pacific and Indian Oceans. It often forms dense thickets on seaside cliffs and sand dunes. Beach naupaka is highly invasive and has become a troublesome weed in South Florida where it was was first reported in 1976, apparently introduced from Hawaii. In South Florida, beach naupaka has established itself on sand dunes and coastal hammocks, displacing native species, and is quickly becoming one of the most common shrubs along the South Florida coast.
As evidenced by its ability to rapidly colonize much of the coastal South Florida environment, beach naupaka is an adaptable shrub and one that is easy to grow.
Light: Full sun. Moisture: Beach naupaka is drought tolerant. Hardiness: USDA Zones 10 - 11. Propagation: Beach naupaka is propagated from seed. The fruits float and the seeds remain viable for more than a year in sea water. However, they will germinate only with fresh water. No doubt the plant also could be propagated by division.
The 'half' flowers of the beach naupaka resemble those of the fairy fanflower (Scaevola aemula) a relative that is becoming a popular garden plant.
Beach naupaka was formerly promoted for beach stabilization programs, but is no longer recommended due to its aggressive tendency to invade and displace native coastal species. The native inkberry is a better choice for seaside gardeners.
The genus Scaevola includes also the cultivated (noninvasive) fanflowers, popular ornamental perennials from Australia. See Floridata's profile for fairy fanflower.
The Florida Exotic Pest Plant Council lists beach naupaka as a Category I species, defined as a plant that is invading and disrupting native plant communities. It is reported that beach naupaka is now supplanting native coastal vegetation, including some Endangered and Threatened Species, in South Florida.