Both single-trunked palms with palmate, fan-like fronds, the Mexican fan palm (Washingtonia robusta) and windmill palm (Trachycarpus fortunei) grow in mild winter regions. They require lots of direct sunlight and moist, well-draining soil to prosper. Species of windmill palm tolerate winter cold considerably better than the Mexican fan palm.
Indigenous to the southern half of Baja California and Sonora in Mexico, Mexican fan palm grows in the desert alongside streams and near springs. Windmill palm hails from central and eastern China, in mixed forests.
Mexican fan palm matures potentially to heights twice that of a mature windmill palm, as well as at a faster growth rate. The Mexican fan palm tends to retain its oldest, dead fronds in a downward "petticoat" below the frond canopy. Windmill palm fronds, once dead, may fold downward along the trunk, but usually drop away to keep the fibrous trunk exposed.
Not as tolerant of winter chill, Mexican fan palm suffers damage when temperatures drop below 20 to 25 degrees Fahrenheit. It grows well in USDA zones 9 through 12 where winter frosts are brief and infrequent. Conversely, windmill palm readily handles winter low temperatures to 5 degrees. This palm finds favor in landscapes in Zones 7 through 10.
Regions with mild winters, hot summers and more arid conditions more heavily utilize the beauty of the Mexican fan palm in landscape designs. Whether planted in rows along avenues, an allee or in groved clusters, this species' canopies provide a graceful, attractive mop-head look upon tall, slender trunks. The persistent dead fronds, the "petticoat," frequently are removed by maintenance workers to make the palms look more refined. It tolerates dry, windy exposures.
Windmill palm, although hardy into subtropical regions, receives preference by gardeners in warm temperate regions because of its excellent cold tolerance. Slow-growing and reaching 40 feet at maturity, it grows in gardens as single specimens or small groupings of various heights. Garden designs place this species in more intimate settings among other trees, as it does not fare well in windy, exposed sites.
The fronds of the Mexican fan palm provide ornamentation for Christian religious services on Palm Sunday, especially in regions with dry soils and arid climates. They do not bear spines on the fronds, unlike date palms. Windmill palm, especially in its native China, traditionally supplied thatch and fiber for making coarse garments, brooms and hanging baskets.