What Is a Screwpine?

The screwpine is not a pine tree at all, but rather a type of monocot tree resembling a palm. About 600 species of Pandanus trees exist, which are commonly used for landscaping, food, weaving and even medicinal tonics in tropical climates. Though some variations exist between this large group, most are mid-size trees with visible roots above the ground, which grow pineapple-looking fruit that actually divides into dozens of miniature fruits.

Screwpines grow in tropical regions, primarily in sandy, alkaline soil. They are found naturally throughout the Pacific islands from Hawaii to North Australia. They have also adapted in California and Florida, where landscapers use them to build interest with their long flowing leaves, exotic fruit and vibrant flowers. Average temperature cannot drop too far below freezing for screwpines to survive.

The trees grow as tall as 25 feet (about 7.6 m), with long frond-like leaves that flow from central points where flowers and fruits are formed. Perhaps the most distinguishing feature of the screwpine is its fan or above-ground roots. Some biologists speculate that the roots evolved to help these trees withstand fierce shore-line winds, despite the looser sandy soils in which they are most commonly found.

Since these trees are dioecious, separate plants form male and female flowers, requiring cross-pollination. Due to this, landscapers will plant them in clusters containing male and female representatives. Screwpine fruit will turn to orange or red from green to indicate ripeness.

In Hawaii, the screwpine's fruit is called hala. According to Maui Magazine, ancient residents put the whole screwpine to use, making roofs and clothes from the leaves, foundations and tools from the wood, and food, paint and medicine from the fruit. The spiked male fruit of certain species were also thought to be powerful aphrodisiacs by ancient Hawaiians.

Those who use this storied tree in landscaping have some considerations. A tropical climate is imperative, and direct sunlight is preferred, though some screwpine trees can thrive with periods of indirect light. They also are frequently planted far from sidewalks and homes since many species not only grow upward quickly, but also outward. Some root thickets extend just as wide as the Pandanus tree is tall. These trees are quick to sprout new saplings too, which is a boon to creating wide swaths of exotic cover but a nuisance to gardeners trying to grow other types of plants.