The Arizona Sycamore ( Platanus wrightii) is a large deciduous tree native to canyons, streams and rivers in south and central Arizona, extending to adjacent western New Mexico and northern Mexico. It is commonly used as a landscaping tree for USDA hardiness zones 7 through 11.
Arizona Sycamores can grow up to 80 to 100 feet tall, though they range between 40 to 70 feet. The trunk can grow to a diameter of 3 to 8 feet, sometimes even larger in very old specimens. The tree’s crown is broad and can spread widely, usually extending as wide as the tree is tall. The trees can live for several decades, with some specimens reaching over 100 years old. However, their longevity can be influenced by various factors such as environmental conditions, disease, and human activity.
The leaves of the Arizona Sycamore are palmately lobed. The leaves are large about 4 to 6 inches (10 to 15 cm) in width, and they are arranged alternately on the branches. The leaves are green on the upper side and a paler green on the underside. The color can vary slightly depending on the age of the leaf and the time of year. The texture of the leaves is typically smooth and sometimes slightly hairy when young. As the leaves mature, they may become slightly rough to the touch. In the fall, the leaves of the Arizona Sycamore turn a golden yellow color before dropping.
The tree produces inconspicuous flowers that emerge with the leaves in April and May. The flowers are monoecious (have both male and female flowers on the same plant). The male and female flowers are segregated into separate flower heads. The male flower heads are dark red and the female flower heads are green. The flowers are arranged in dense globose unisexual heads, either solitary or in racemes. The actual flowers are small and are not particularly showy.
The bark of the Arizona Sycamore is similar to that of other sycamore species, such as the American sycamore (Platanus occidentalis) and the California sycamore (Platanus racemosa). However, the Arizona Sycamore’s bark is described as being more mottled and peeling than that of the American sycamore. The bark can be said as being thin, white, and peeling, with brown-gray patches.
Arizona sycamore is prevalent in riparian areas of the Madrean Sky Islands, mountain sky islands in southeast Arizona, extreme southwest, Bootheel region of New Mexico and along the San Francisco River in Western New Mexico, northeastern Sonora, and extreme northwest Chihuahua).
The species is more prevalent west of the Madrean Sky Islands region, still in the central and northeast Sonoran Desert, an area around the Organ Pipe Cactus National Monument at the Arizona-Sonora border, with the species range extending in Sonora in the Occidentals, or its western foothills. Scattered reports have been made farther east in the Sierra Madre Occidental.
Common American Sycamore Diseases and Pests
Diseases
- Anthracnose: This fungal disease can cause leaf spots, blight, and twig dieback. It thrives in cool, wet weather and can be controlled through proper pruning, sanitation, and fungicide application.
- Powdery mildew: This fungal disease appears as a white, powdery coating on leaves, stems, and flowers. It can cause leaf drop and reduce overall vigor.
- Root rot: Caused by various fungi, root rot can lead to wilting, yellowing leaves, and branch dieback. It’s often associated with poor drainage and overwatering.
Pests
- Aphids: These small, soft-bodied insects can cause leaf curling, yellowing, and distortion. They also produce honeydew, which can attract ants and promote sooty mold growth.
- Sycamore lace bugs: These insects feed on the undersides of leaves, causing stippling and yellowing. They can also produce black, tar-like excrement on the leaves.
- Sycamore scale: These small, armored insects can cause leaf yellowing, stunted growth, and branch dieback. They also produce honeydew, which can attract ants and promote sooty mold growth.