Blackthorn bushes
You’ve probably seen those “Irish shilelagh” sticks or “Irish walking stick” made from some brambly-looking wood with little gnarls and knobs all over it. That is the wood of the blackthorn bush which grows all over Ireland, mostly in the hedges dividing fields. It’s called “blackthorn” not so much for the wood (which can look black), but for the black berries that grow among the thorns.
Prickly and strong, the thorns are stout things, growing up to an inch in size; straight, pointy and strong.
Mind any tearable clothing when around the blackthorns – they can be treacherous things.
Because the blackthorn wood is strong and grows easily and plentiful, it was often used to make walking sticks or, yes, shilelaghs, which were more often than not used for farming and not beating off hordes of vikings or englishmen.