A little more on ents:
Ents are extremely strong. When attacking Isengard they litteraly hew and break the stone wall surrounding it. Their hands cling to the rock like old treeroots and crack it. They break iron posts and throw them high into the air. As Treebeard puts it himself, they have the strength of the earth itself in them.
When going to war, the Ents are roused, they are wild and terrible. They do not like being roused however, and they only take part in war at all in the assault on Isengard and the slaying of the orcs at Helm's Deep. The Ents (Treebeard in any case) prefers walking in the forest talking to the trees and taking care of them.
Ents take a long time to think, and even longer to say anything in their own language. Indeed, their language is different from any other language in that the names of things grow longer as the thing grows older. As an example, Treebeard's name in old "Entish" would take a long long time to say (days, maybe weeks), as he is old as the forest of Fangorn itself.
The entwives were female Ents that dissapeared a long time ago, after the great war. Long ago they lived together with Ents, but they grew different and had different interests. The Ents preferred the forest as it is in the wild, while the Entwives would make gardens and tend them and organize them as they fashioned. At some point the Entwives left the Ents, and after the great battles at the end of the second age they were not seen again.