Edward F. Gilman, Dennis G. Watson, Ryan W. Klein, Andrew K. Koeser, Deborah R. Hilbert, and Drew C. McLean
Introduction
Creating a striking landscape effect wherever it is used, screw-pine has a pyramidal, sometimes irregular, open, but much-branched silhouette. The smooth, stout trunks is topped with full, graceful heads of long, thin leaves, three feet long and three inches wide, emerging spirally from stubby branches. It is not a true pine tree. The blue-green foliage color adds to the striking nature of this exotic tree. The leaves are edged with small red spines and are used to make mats and baskets in the tropics. Branches have prominent leaf scars which encircle the stems. Large brace-roots emerge from the trunk several feet above the ground, helping to support the plant. Screw-pine is capable of reaching 60 feet in height but is not usually seen over 30 feet in USDA hardiness zone 10 and 11, with a spread of 20 feet. Growth rate is slow to moderate, depending upon fertilization and watering schedules, and screw-pine is very popular for use as a specimen or container planting.
Figure 1. Full Form - Pandanus utilis: screw-pine Credit: UF/IFAS
General Information
Scientific name: Pandanus utilis
Pronunciation: pan-DAY-nus YOO-tih-liss
Common name(s): screw-pine
Family: Pandanaceae
USDA hardiness zones: 10B through 11 (Figure 2)
Origin: native to Madagascar
UF/IFAS Invasive Assessment Status: not assessed/incomplete assessment
Uses: reclamation; deck or patio; specimen; container or planter; street without sidewalk; highway median
Soil tolerances: clay; sand; loam; alkaline; acidic; wet to well-drained
Drought tolerance: moderate
Aerosol salt tolerance: high
Other
Roots: not a problem
Winter interest: no
Outstanding tree: no
Ozone sensitivity: unknown
Verticillium wilt susceptibility: unknown
Pest resistance: free of serious pests and diseases
Use and Management
Although the male plants possess conspicuous, fragrant flowers, it is the female plant which is preferred for landscape use because of the large, eight to nine-inch, globular fruits which hang from "cords". The fruits are made up of 100 to 200 tightly compressed drupes, similar to those of a pineapple, and change from green to yellow when ripe. There is only a small amount of edible pulp but the fruits are quite showy.
Screw-Pine produces fruit when grown in full sun but young plants may be kept in the shade. Soil should be well-drained and plants kept well-watered. Screw-Pine may be considered messy due to the constant leaf-drop throughout the year.
Veitch Screw-Pine or Ribbon-Plant (Pandanus veitchii) has white-banded, spiny leaves, does not fruit, and is often used as a pot plant. Sander Screw-Pine (Pandanus sanderi) has denser, more tufted foliage with golden yellow bands from center of leaf to margin.
Propagation is by seed (soaked 24-hours before planting), basal sucker division, or large cuttings.
Pests and Diseases
No pests or diseases are of major concern but occasionally scales.
References
Koeser, A. K., Hasing, G., Friedman, M. H., and Irving, R. B. 2015. Trees: North & Central Florida. University of Florida Institute of Food and Agricultural Sciences.
Koeser, A.K., Friedman, M.H., Hasing, G., Finley, H., Schelb, J. 2017. Trees: South Florida and the Keys. University of Florida Institute of Food and Agricultural Sciences.
