This thread prompted me to go and cut the blackthorn stick I noticed last year. It's gorgeous - a dead straight limb about 8 feet long and 2.5 inches in diameter, which has grown up out of another limb, which will provide plenty of handle. I'm half-tempted to make a wizard's staff out of it next year, but my ankles are giving me gyp and I think a proper blackthorn walking stick will get more use.
Just remember that a wizard's staff has a knob on the end!

In my case, a big knob...
Rat