Archontophoenix is a small genus of feather palms from Australia. They are moderate size to large, very majectic, tropical looking palms with crownshafts. They do well in cool climates, but are not very cold hardy. Some have tried A. var. 'illawarra' in the Pacific Northwest, after hearing a report of it surviving -8°C/17°F in California. However, this palm has definitely not shown a lot of promise in the Pacific Northwest and it seems to be quite tender. Like Rhopalostylils, this is a very cool tolerant palm that would be happy here in the spring, summer and fall, but does not quite have what it takes to survive Arctic blasts.
Archontophoenix likes rich soil and lots of water. They are easy and fast-growing from seed and their very elegant tropical look makes them among the most worthy of garden plants. But, my personal guess is that they will not ever grow in the Northwest, north of Curry County, Oregon.
My best guess on Archontophoenix hardiness translated to our maritime climate, roughly, would be as follows:
A. purpurea 'Mt. Lewis': -5°C/23°F
A. cunninghamii: -4°C/25°F
A. var. 'Illawarra': -3°C/27°F
A. maxima: -3°C/27°F (might be hardier, according to some reports)
A. alexandrae: -2°C/28°F
A. 'Peach River': not sure