This genus contains only a few species, one indigenous to California, one to Europe, two to Japan and one to Canada. It grows to a height of sometimes forty feet, is bush-like in habit, has a willow-like bright-green leaf and bears a purple or red fruit. It delights in a light sandy soil in a sheltered situation with plenty of moisture, preferably the margin of a lake or swamp.

Propagate by seeds sown one-eighth of an inch deep in Spring, or by cuttings placed in the open ground in October.