Betula occidentalis Hook. Syn. Betula fontinalis Water Birch or American Red Birch Native to western N. America, where it tends to be rather shrubby forming dense thickets along streamsides. Height to 6-7.5m (20-25ft) but may be shrubby in cultivation. Flowers open in April, male catkins 5cm (2in) long, females about 0.8cm (1/3in), ripening to erect, stalkless fruiting catkins 2.5-3.7 cm (1-1½in) long, only slightly downy. These shed seeds in September. Leaves are dark green with only 3-5 pairs of veins and no hairs underneath with rounded or slightly heart-shaped bases. Young leaves and twigs are rather sticky. Bark is shiny dark brown, almost black, and does not peel into layers. Z3.