I have seen goats and camels get very sick (I even think one of the goats may have died) after eating azaleas. They were immediately taken care of medically after ingesting the leaves, but it was still real bad for the animals. I’m not sure how a tortoise would react. Some things that are no good for mammals don’t seem to be as bad for tortoises, but I would avoid them anyways. You don’t want to learn anything the hard way.