River cane(each shoot or culm)has a 3 year life cycle. The first year it grows to it's ultimate height. The second year it matures and the shoot becomes thicker. At each node there is a paper like sheath. When that sheath begins to deteriorate, or has fallen off, the cane should be mature enough for arrow making. Also the color of new shoots is bright green. towards the end of the second year it begins to dull out and by the summer of the 3rd year it will be from olive green to tan. Once it turns tan, in the wild, it too far gone for arrows. Ideally, the fall to winter of the second year is the time to harvest it. Pat