The time of year is not critical but fall and winter is better for the sake of bugs and snakes. What is more important is to harvest mature culms. Native canes have a 3 year life cycle; the first year it grows to its ultimate height. The second year it matures(walls thicken) and after the 3rd growing season it begins to die. Ideally you want to harvest it after the second growing season until it begins to die(no longer green on the stump) during the 3rd growing season. A couple of ways of telling if it is mature is when the paper like sheath has started to deteriorate or is already gone and when the culm turns from bright green to a yellowy green or olive green.
What kind if boo do you have growing in your yard? Pat