Beyond their size and leaves, there is little to distinguish the American sycamore (Platanus Occidentalis), also called the buttonball, buttonwood tree or Eastern sycamore, from the California sycamore (Platanus racemosa), also called Western sycamore and "aliso" in Spanish. If you live in a colder climate, the American sycamore likely a better choice. If you live in a warmer, drier climate, the California sycamore may be more suitable.
The American sycamore is native to moist, warm climates of the southeastern United States, and you can grow them in U.S. Department of Agriculture plant hardiness 4 through 9. California sycamores grow naturally on the sides of streams, moist valleys, arid foothills and rocky canyons in the mountains coast and central areas of California south into Mexico. You can grow them in USDA hardiness zones 7 through 10.
American sycamores like rich soil with lots of humus, although they will grown in average to consistently moist soil as long as it drains well. Dry soil can shorten its lifespan. California sycamore also likes moist soil, but its natural range in the drier climate of central and Southern California means you can grow it in a greater range of environmental conditions.
The American sycamore is a slightly larger tree, growing from 75 to 90 feet high. The California sycamore grows from 30 to 80 feet high with a canopy spreading from 20 to 50 feet wide. Both trees are described as fast-growing, meaning under good conditions they will grow more than 26 inches a year. Fast-growing California trees grow from 15 to 20 feet in the first five to 10 years.
The medium to dark green leaves of American sycamore are 8 to 12 inches long and 4 to 8 inches wide with three to five lobes and coarse teeth on the edges. They turn yellow-brown in the fall. Light to dark green California sycamore leaves are 5 to 10 inches long and 5 to 10 inches wide and also turn yellowish brown. Their five long lobes extend more than half the length of the leaf. The lobes of American sycamore are shallower than the deep lobes of the California sycamore.
- Missouri Botanical Garden: Platanus Occidentalis
- Lady Bird Johnson Wildflower Center, University of Texas: Platanus Racemosa
- Florida Cooperative Extensive Service: Platanus Occidentalis Sycamore
- University of California, Irvine: Platanus Racemosa
- Arbor Day Foundation: California Sycamore (Platanus Racemosa)
- City of Glendale Public Works: California Sycamore – Platanus Racemosa
- Ohio Department of Natural Resources: American Sycamore (Platanus Occidentalis)
- Santa Monica Mountain Trails Council: Sycamore