Cold hardy, compact and shade tolerant, the windmill palm (Trachycarpus fortunei) is a surprisingly tough, versatile tree, so the care of a windmill palm tree is relatively easy. The palm grows to an average height between 20 to 40 feet, producing a lush, symmetrical crown up to 10 feet wide. With proper maintenance and care, the windmill palm can be grown in a wide range of growing conditions.
Tree Hardiness Help
Windmill palm is among one of the most frost-tolerant palms available and is hardy in U.S. Department of Agriculture plant hardiness zones 7 to 10. Mature trees can generally survive temperatures as low as 10 degrees Fahrenheit, but younger trees often can't withstand quite as cold of temperatures.
If temperatures approach single digits, however, windmill palm can benefit from winter protection. Cover and secure the palm's crown with a plastic sheet. Apply a thin layer of organic mulch around the base of the palm, keeping the mulch from actually touching the trunk.
Location, Location, Location
A windmill palm tree looks its best in partial or even full shade. In the cooler end of its hardiness zones, windmill palm will tolerate full sunlight if the soil is kept consistently moist. The palm's crown will generally be more compact in sunny situations.
Windmill palm is moderately tolerant of salt and wind and can be planted close to the seashore, although the fronds will get ragged in especially windy, exposed locations. A location with some wind protection, such as behind a sand dune or near a building, is ideal.
Windmill Palm Soil and Water
The palm prefers fertile, well-draining soil, although it will survive in just about all soil types except compacted, consistently flooded soil. Amend the soil with compost to make it rich and fertile before planting. If planting multiple palms, space plants 6 to 10 feet apart to prevent competition for nutrients and water and to provide ample air circulation.
Windmill palm is slow growing and can benefit from regular irrigation. Water enough to keep the soil moist, but not waterlogged. A windmill palm doesn't like to have wet feet, and it's susceptible to root rot, which can kill the tree, if there's too much moisture in the soil. Although drought tolerant, windmill palm will become stunted during long dry periods. Mulching around the base of the windmill palm helps to keep the soil consistently moist and keeps it from drying out as fast.
Windmill Palm Fertilizer Facts
To boost growth rate and increase health, fertilize your windmill palm with a slow-release 10-10-10 fertilizer. Fertilize palms monthly with 1/2 to 2 pounds of fertilizer per month during the growing season, with mature palms getting more fertilizer and young palms getting less. Apply fertilizer around the soil under the canopy, taking care not to place fertilizer directly against the trunk. Follow label instructions exactly, and water well before applying to keep from burning the roots.
Pruning Windmill Palm
The care of a windmill palm is relatively minimal, but occasional pruning helps keep the tree looking attractive. Use a sanitized pruning tool to cut out the yellow and brown leaves and the older flowers to clean up the tree.
Michelle Wishhart is a writer based in Portland, Ore. She has been writing professionally since 2005, starting with her position as a staff arts writer for City on a Hill Press, an alternative weekly newspaper in Santa Cruz, Calif. An avid gardener, Wishhart worked as a Wholesale Nursery Grower at Encinal Nursery for two years. Wishhart holds a Bachelor of Arts in fine arts and English literature from the University of California, Santa Cruz.