The king palm is the patriarchal monarch of all palms because of its elegant fronds, beautiful symmetry and tropical effect in the landscape. While it is not the largest of the palms grown locally, it can reach 40 to 60 feet tall and commands a royal prominence along many of our city streets.
The king palm has a solitary, smooth, light gray trunk that is “crowned” with a lush umbrella of arching fronds, each 6 to 10 feet long. The pinnate (feather-like) fronds have dark green leaflets that are up to 1 feet long and 3 to 4 inches wide.
A green to purplish-brown columnar “crown shaft,” 2 to 3 feet long, rises just above the top of the trunk; this is actually formed from the fronds’ leaf bases that are compressed together, one on top of the other, with the newest ones in the very center. The king palm is considered “self-cleaning” because, as the newer fronds grow, they push against the oldest one on the outside layer, forcing it to peel away and shed naturally, without requiring any pruning by humans.
From November to February, pendulous, multi-branched, whitish inflorescences (flower-bearing stems) break out of their enveloping spathes (bracts) in the area between the trunk and the crown shaft — and, once fully extended, display long strings of hundreds of tiny mauve-pink to lilac-colored, slightly fragrant, flowers. Male and female flowers occur on the same inflorescence. After pollination, the flowers develop round, green fruits, 1 inches in diameter, that ripen gradually to a stunning bright red in the summer to fall.
The king palm is a native of Australia, where it grows in the wet subtropical regions of New South Wales and Queensland. There, it has the common name of “piccabeen palm,” derived from the Aboriginal name for the palm, “Pikki.” Its botanical name is Archontophoenix cunninghamiana; the genus name comes from the Greek words “archontos” (meaning chieftain or ruler) and “phoenix” (the date palm); the specific epithet honors the 18th century botanist and surgeon James Cunningham.
Despite its subtropical origin, the king palm does quite well in our Mediterranean climate, particularly once well established. It will do better with additional irrigation, but most have managed to survive through the long dry seasons and even the recent drought. It likes full sun to partial shade. It does prefer a moist, non-acidic, well-drained soil, though it will tolerate heavier soils. Under good conditions, it can grow up to a foot per year! The king palm can be planted singly or in groups of two or three for a more dramatic effect.
While normally quite pest-free, king palms can suffer infestations of spider mites or mealy bugs, and are susceptible to “pink rot,” a serious (and sometimes deadly) fungal disease that usually attacks stressed or damaged palms. They can also develop root rot if the soil stays too wet without draining. They are cold hardy to 28 degrees; young trees can be killed if the temperature falls below 25 degrees.
The king palm is remarkably wind-tolerant, but its fronds keep their lush appearance best when in sheltered locations. If the fronds fade to light-green and then to yellow, the palm is telling you it needs nitrogen and micronutrients. To solve the problem, apply a fertilizer formulated specifically for palms during late winter or early spring.
In Santa Barbara, king palms have regularly been planted as street trees over the years and are seen on the 400-1000 blocks of Chapala Street (planted in recognition of the contributions of past presidents and board members of Santa Barbara Beautiful); on the 00-200 blocks of East Victoria Street; on the 2900 block of State Street; and interspersed with queen palms on the 800-1400 blocks of Anacapa Street and the 100 block of East Anapamu Street.
Tree-of-the-Month, presented by Santa Barbara Beautiful, increases awareness and appreciation of Santa Barbara’s many outstanding trees. The nonprofit organization partners with the Parks and Recreation Department to fund tree planting along city streets.