Sabal causarium - Puerto Rican hat palm

Sabal causarium is a large palm tree native to the Caribbean, specifically Hispaniola, Puerto Rico, and the British Virgin Islands. It is commonly called the Puerto Rican hat palm, as its leaves were locally used for making wide-brimmed hats. In its native lands, it grows in pine forests and rocky areas, and easily colonizes old fields and fallow land. It is characterized by a slender habit, with a straight, smooth, grey false trunk topped by a relatively narrow, somewhat shaggy crown of fronds. Its behaviour in European climates is still not well understood, but it seems to be quite resistant to cold and drought once established. This is a plant that will delight collectors of rare species and enthusiasts looking for a challenge.

The Sabal causarium belongs to the Arecaceae family. It can reach a height of 16m (52ft) in nature, shorter in European climates. This species exhibits slow to very slow growth, especially during the early years of cultivation.

It develops a single false trunk (stipe), cylindrical, straight, robust, slender, grey in colour, and smooth, sometimes reaching 50cm (20in) in diameter and 8m (26ft) in height. The stipe forms after 10 to 12 years. The foliage is arranged in a terminal crown at the top of the stipe, eventually spanning 4m (13ft) in width. The crown consists of 20 to 30 costapalmate leaves, which means they are palmate leaves arranged in a fan shape around a central axis. In the Sabal causarium, each leaf, 1m (3ft) wide, has a medium green colour. It is divided into 60 to 120 rigid segments, with a cleft at the tip. The flowering, which occurs on mature individuals, consists of branched inflorescences with bisexual white flowers (both male and female), erect or pendant, extending beyond the leaves. They give way to oval to globose black fruits measuring 1.5 to 1.9cm (1in) in diameter.

The Sabal causarium is a beautiful specimen to plant in coastal gardens, either as a solitary tree or in rows, especially in warm climates. Its hardiness will likely depend on soil drainage, duration of frost, and ambient humidity. Plant this rare and prestigious species near an entrance or on either side of a gate. When planted as a solitary tree near a swimming pool, it will look stunning and amaze your visitors.