Trachycarpus wagnerianus is unknown in the wild but may have originated in cultivation in Japan where it was first discovered early last century. It is still somewhat hard to find and costs more than the fortunei due to demand.
This palm is similar in appearance to the Windmill Fan Palm, Trachycarpus fortunei but its overall appearance is smaller and more dainty and It is tolerant of more wind and coastal conditions than T. fortunei. We feel it is one of the Best Palm choices for the Northern Oregon and Washington coastal areas.
Trachycarpus wagnerianus has smaller (2 to 3 feet wide), stiff, deeply-cut dark green leaves that are rounded in outline and held on shorter petioles than T. fortunei, which gives the plant an overall more compact look. The trunk grows to 15 feet and is 8 to 10 inches in diameter Hardy to 5º to 10 degrees F.or lower when mature Younger or potted plants will need some protection at 10 º to 15º .
When younger they make a good potted palm however will need protection if left outside in the pot on colder winter nights. Growth rate very Slow to Slow. The leaves of younger palms are nearly circular, but those of older plants tend to be hemispherical. At all ages they are relatively small, from 18 to 26 inches wide, and are borne on 2- to 3-foot-long petioles. This is an easily identified species with small, stiff leaves (much unlike that of Trachycarpus fortunei). New growth is margined with a short but dense white woolly tomentum. To plant and grow them west of the Cascade Mountains of the Pacific NW, you will need to make a mixture containing 50% good potting soil, with 25% sand & 25% small gravel. (Never use beach sand in the soil mix) Have the root ball raised about 1/4 out of the hole but mounded up with the soil mixture. Try to plant in an area that will get morning & mid day sun during the winter months. I recommend using a water meter the first few years.
For more information on the planting and care click on this link