You have to be sure to harvest mature cane for arrows. River cane, hill cane and switch cane, all US natives have a 3 year life cycle. The first year the culms(canes) reach their ultimate height and diameter but the walls are thin. After the second growing season and until they die after the 3rd growing season the walls thicken as the culm matures. After the second season until the culms begin to turn tan in color the 3rd year is the best time to harvest for arrows.