Roystonea borinquena aka Puerto Rican Royal Palm

Roystonea borinquena is an evergreen palm in the Arecaceae family. Its common names include Puerto Rico royal palm and mountain-cabbage. Its native range runs from Hispaniola to the Virgin Islands. It grows in Puerto Rico, Vieques, and St. Croix. PACSOA also lists Tortola, though that record remains uncertain. It grows in forests, pastures, and along river banks. Moist limestone hills provide good sites for natural regrowth.

This palm has one tall trunk and no branches. Useful Tropical Plants gives a height of 49 feet [15 metres]. PACSOA reports taller trees reaching 82 feet [25 metres]. The smooth, gray trunk widens at its base. Reported trunk widths reach 2.3 feet [0.7 metres]. A green crownshaft rises above the trunk. It measures about 3–10 feet [1–3 metres] long. The crown holds as many as 15 pinnate leaves. These droop and reach 11.5 feet [3.5 metres] long. Bees pollinate the flowers, but the sources give no bloom season.

Grow this palm in full sun with good soil drainage. It prefers limestone-based soil and grows well in moist ground. It also tolerates partly compacted fill and polluted city air. Its native climate stays free of frost. Rainfall there totals about 49–98 inches each year. The mean yearly temperature is around 25°C. Young plants grow fast, and seeds germinate with ease. Seedlings can take full sun from the start. Even mature palms move well, and established trees withstand hurricane winds.

People plant this species along roads and in city spaces. The sources report that its roots do not damage nearby paving. This makes it useful where planting space is tight. People have used its trunks for rural buildings. The hard outer wood supplies boards for floors and siding. Leaves provide roof thatch, while flattened leaf sheaths form walls. Young leaf strips also supply material for woven chair parts. Fresh leaves serve in local Palm Sunday events.

Dry-wood termites can attack boards made from the trunk. The supplied sources name no other pests or diseases. Useful Tropical Plants lists no known hazards. However, that does not establish safety for people or pets. Its account does not confirm that this species has edible buds. The food notes rely on related palms, so edibility remains uncertain.