The Windmill Palm Tree, scientific name Trachycarpus fortunei, is one of the most popular palms because of its beautiful appearance and easy maintenance. This super cold tolerant palm is great for landscapes in USDA zones 7b-11.
Being native to China, this palm likes climates with cool summers and can be grown in states like Alaska, Alabama, Delaware, Maryland, Massachusetts, Mississippi, New Jersey, New York, Oklahoma, Tennessee and more.
|Scientific name:||Trachycarpus fortunei|
|Common names:||Windmill Palm, Chusan Palm, Chinese Windmill Palm.|
|Origin:||Native to central and eastern China.|
|Growth Rate:||Slow. Up to 25 ft in height and 5 ft wide.|
|Cold Tolerance:||USDA Zones 7b (5 – 10 F) to 11 (above 40 F).|
|Light Req:||Partial shade to full sun.|
|Water Req:||Drought tolerant.|
|Soil Req:||Widely adaptable.|
|Fruit:||Yes. Blue. Not edible.|
|Propagation:||By seeds, germinating in 2 months|
Windmill Palm Appearance
Trachycarpus fortunei is slow growing palm that can reach 25 ft in height and 5 ft wide but is also known to grow as tall as 40 ft in the wild.
It has a slender single trunk that is around 8 to 10 inches in diameter. The trunk is covered with a loose mat of coarse gray or brown fiber and is a bit narrower at the base.
The windmill palm has palmate, sword-like leaves that are 4 ft in diameter. They range from dark green to yellow-green in color that seem almost silvery on the underside.
Leaves grow upward more so than outward. The petiole is about 1 ½ feet long and armed with sharp thorns.
Windmill Palm Flowers and Fruits
The windmill palm is dioecious, male and female flowers are borne on separate plants. In the early summer, it produces large plumes of yellow flowers on the male plants and greenish on the female plants
Flowers are held on 3ft long branched stalks. Later flowers of the female plants transform into bluish-black fruits that are about 1/2 in (1.3 cm) in diameter. The fruits get ripe in the mid fall. The Windmill Palm fruit is not edible.
How To Care For Windmill Palm
This plant can adapt to wide range of soils as long is it drains well. Although it can tolerate drought for short period of time, it does best when watered and fed regularly. It has salt tolerance.
Despite being mildly susceptible to lethal yellowing and phytophthora bud rot, it rarely develops nutrient or pest problems unless weakened or injured. It looks best when planted in an area with some wind protection to prevent leaf tearing.
Trachycarpus fortunei likes partial shade or full sun. While it can even tolerate full shade, the growth rate will be much slower. The amount of sunlight needed really depends on the climate.
If your area has hot summers with frequent droughts, it’s better to plant it in partial shade to prevent leaf burn.
On the other hand, if you live in a climate with cool summers and cold winters, full sun would be a better choice. If you are growing it indoors, find a bright spot with plenty of sunlight.
This plant grows in any kind of soil, even heavy clay, so there is no need to amend a soil when planting a newly purchased plant.
It will succeed in alkaline or acidic soil as longs as it has good drainage. Therefore, test the drainage of the soil before planting it.
This plant is very prone to drought stress until fully established which takes about 3 years. So, water newly planted palm every other day, for the first three months, and weekly for the remainder of its first year. Don’t let the soil dry out, especially during hot summer days.
If you are growing it in a container, make sure the soil is moist but well drained. Don’t let it sit in soggy soil since it might lead to root rot.
While it’s not fussy about the soil, it thrive with ample soil fertility so try to fertilize it regularly to prevent nutritional deficiency. Apply good quality palm fertilizer that has continuous release formula twice a year during growing season.
This palm seem to like occasional application of Epsom salt (magnesium sulfate) in spring. If it’s growing in clay soil poor in iron, add minerals that include high chelated iron to keep the foliage greening and canopy developing.
It is great for growing in USDA Zones 7b (5 – 10 F) to 11 (above 40 F). Trachycarpus fortunei is extremely cold hardy palm that can grow throughout all of the zone 8 and most of the zone 7b with little or no winter protection.
They can even be grown in zone 7a and some microclimates of zone 6 with some winter protection, but expect full loss of foliage during cold winter months.
Keep in mind, there is a big difference in cold tolerance between young and mature Windmill palms. As this plant matures, it develops much larger root system thus becomes much hardier.
There has been reports of mature windmills in Ohio surviving -14F. While individual plants vary, on average a mature windmill can survive lowest temperatures of about -10F without protection. We are talking about survival, so don’t expect it to keep all of it foliage. Significant leaf damage usually occurs at about 10F.
This palm seem to be very sensitive to wind chill damage, therefore should be sheltered as much as possible. Of course it gets harder and harder to provide wind protection as it gets larger. The great news is that it will quickly recover the next growing season.
I think that if you live in a colder area, heaving a nice looking palm 8 months out of the year might not be such a bad trade off.
This plant doesn’t require much pruning. Just trim off dry brown fronds as close to the trunk as possible.
Insects and Diseases
Very few insect and disease problems exist to endanger growing windmill palm trees. Scales and palm aphids are pests that usually cause problems.
Also, it may be infected by root rot, moderately susceptible to lethal yellowing disease, and leaf spots.
Propagated by seeds. Trachycarpus fortunei seeds will germinate in 8 to 12 weeks without a lot of fuss. Sow seed at 75°F in spring or fall.
First, soak the seeds in water for a few days. Next, plant seeds, as deep as they are wide, in rich, potting soil mixed with peat moss. Place them in bright sunlight and water regularly.
It might take one to seven months for seeds to germinate. You can replant it once the seedling’s first leaf is over 2-inches long.
Landscaping With Windmill Palm
It makes an excellent focal point in small garden or courtyard. In larger landscape several windmills look better. If you planting it next to the house or other building, leave about 5 feet for the fronds to fan out.
For planting in the row, leave about 7 feet between plants. This stunning palm is perfect for lining a driveway or accenting entryway. It looks great alone or in groups with different heights, especially if planted in front of a fence or a wall.
They do well with wide variety of companion plants and can anchor a planting bed with flowering shrubs or colorful tropical plants.
Growing Windmill Palm Indoors
Windmill palms make great indoor houseplant because it’s slow growing, adapts to different types of soil, and can tolerate low humidity levels. To grow it indoors successfully provide it with plenty of sunlight, regular watering and fertilizing.
You can take it outdoors during warm months but make sure to do it gradually to avoid sunburn. Indoor palms usually get stressed when suddenly exposed to direct sunligh.
Keep the soil moist during hot summer months, but allow for the soil to dry between watering in fall and winter. Use distilled or filtered water to avoid chemical buildup.
This slow growing palm doesn’t need annual repotting like a lot of other houseplants. You should re-pot it every three years to freshen up the soil even if you are using the same pot.
Fertilize it twice a year, in the spring and in the summer with slow release fertilizer for indoor palms. Watch out for magnesium deficiency which might cause yellow spots on the leaflets.
Other Butia Varieties
The genus Trachycarpus contains several closely related species with the same high cold tolerance. For example Trachycarpus wagnerianus, also known as Miniature Chusan Palm, is a dwarf version of windmill palm, but has stiffer and shorter leaves that are less sensitive to wind.
The Trachycarpus takil (Kumaon palm, Himalayan windmill palm) found it extreme elevations in he Himalayas, is considerably more cold hardy than Chinese windmill palm, easily able to survive regular drops below 0F. It also can grow much taller than Trachycarpus fortunei, with larger crown and thicker, often bare trunk.
The Trachycarpus martianus (Nepal Windmill Palm) and Trachycarpus latisectus (Sikkim Windmill Palm or Windemere Palm) are less cold hardy than windmill palm and have bare, ringed trunk rather than the furry one.
Frequently Asked Questions
In this section I want to answer some of the most popular questions I get about this plant.
How Fast Do Windmill Palms Grow?
It’s a slow growing palm the grows 10-15 inches a year reaching its maximum height of 25 feet. Enough moister in the soil speeds up plant growth and improves the appearance. Water it more during warm months and reduce watering in the cool winter months.
Although Windmill Palm is very drought tolerant, irregular watering and drought will slow its growth rate dramatically.
Are Windmill Palm Fruits Poisonous To Dogs and Cats?
According to ASPCA, Windmill Palm fruits are NOT toxic to cats and dogs. You pet might have an upset stomach but these fruits are not poisonous.
How to Protect Windmill Palm From Cold?
While windmills are very cold tolerant, if you are growing it in zone 7, it will need winter protection. The minimal protection you can offer is heavy mulching and application of fungicide/bactericide spray.
For more serious protection, build a wire or burlap enclosure about 1ft away around the trunk. It should be tall enough to protect the entire trunk and the lower portion of the crown, so called ‘crown cavity’.
Spray entire plant with anti-transpirant, which reduces moister loss, and fungicide/bactericide spray to prevent crown rot. Next, fill the entire enclosure with pine straw mixed with dry leaves or just dry leaves.
This treatment can help you overwinter your windmills with temperatures dropping below 0F!