None directly under - 2 or 3 feet away maybe, if you're prepared to water when its dry.

Euphorbia robbiae is the only one I can think of, and that is growing strongly for me under a big conifer where the ground is extremely dry. If you put the first one a few feet away from each tree as Bamboo says you may well find it will spread nearer the trees as time goes by. Once well established it usually romps away.