Sabal causiarum

Sabal causiarum, the Puerto Rican Hat Palm, is the heavyweight of the palmetto family. A single smooth gray trunk swells to as much as four feet through, the thickest of any Sabal, and rises forty or fifty feet beneath a crown of enormous costapalmate fans six feet across, stiff and deeply divided, each with a conspicuous tan ligule at the base of the stalk. Cream flowers on branched stalks longer than the leaves give way to round black fruit. Where the native palmettos read as graceful, this one reads as monumental.

The palm grows wild in Puerto Rico, on Hispaniola, and on a few of the British Virgin Islands, in open country near sea level. The name is a hat. Causia was the broad-brimmed sun hat of ancient Macedonia, and causiarum, of hats, records the industry that grew up around the palm: by 1901 the village of Joyuda on the west coast of Puerto Rico was turning the fans into hats in quantity, and the common name has followed the palm ever since. The leaves also served for thatch, brooms, and baskets, in the long tradition of the genus.

What makes the Hat Palm interesting to a Southern gardener is that a palm from the Caribbean has no business being as cold hardy as this one is. Established specimens shrug off the low twenties without leaf damage, the palm is rated to Zone 8b, and growers have raised the species as far afield as Houston and the coastal Pacific Northwest. Among the big trunked Sabal, only the Texas Palmetto comes close for cold tolerance, and the Hat Palm grows faster, which for a palmetto is saying something. Our plants came from Joe LeVert of Aquinas High School in Augusta, Georgia, whose palm collection has sent more than one rarity down the road to Aiken, and Woodlanders is growing a small first batch on in one-gallon pots. This is one of the rarest palms we have ever listed.

Give the Hat Palm what any monument needs: room. Full sun, sharp drainage, and a site where a four-foot trunk and a thirty-foot crown will not be an argument in twenty years. The palm tolerates drought and salt once established and asks for little else beyond patience and an occasional feed, since the big fans show potassium hunger on lean ground. Plant as a specimen on a lawn or a wide avenue, where the trunk can be read whole, and underplant with sun-loving, salt-tolerant companions once the canopy lifts. A palm for the gardener who wants the largest palmetto that can be grown this far north, and a story about hats to go with it.