The great differences in elevation, exposure, and precipitation that exist in the North Cascades promote a range of flowering times. Some plants are flowering by late February and early March in the low elevation forests, and as late as August and early September in the alpine zone. While most of our flowers are insect or wind pollinated, those blooming during the relatively warmer days of April and May, such as salmonberry, Indian plum, and red-flowering currant will be visited by hummingbirds returning to breed.