I went for a walk in our woods the other day with my pruners on my hip. This time of year it is easy to see sourwood trees because of their color. In a few weeks the leaves will be down and I'll take pics of more visible sourwood shoots.
These pics aren't real clear because of the bright sun but if you look closely you will see the sourwood shoots sticking straight up above the clusters of brightly colored leaves.
...some are bigger than others. These two will be atlatl shafts with the longest being about 75" long...
Each shoot is one years growth. For shafting you want shoots after their second growing season. From these pics you can see how the sourwood grows with a shoot and a cluster of branches at the top and another shoot the next year and a cluster of branches, etc...