Yes it does grow in Southern Ontario, but only where they did plant it, it's not growing in the wild, and yes it has thorns, one reason they used it for fencing.I don't think that Bois d'Arc (also called Osage Orange) grows as far north as Canada, but it often grows along fence rows and along creek beds in Texas. Bois d'Arc trees have large thorns on the limbs. The wood is very tough, but turns reasonably well with sharp tools. A dead giveaway on identifying the wood is that freshly cut Bois d'Arc is very bright yellow, but the sad news is that the beautiful color doesn't last very long and soon turns to a rich almost chocolate brown.