Both jade and kalanchoes are considered nonpoisonous. They also both don't need much water, so they are pretty easy keepers. If you'd like an indoor tree, the Norfolk pine and the Madagascar dragon tree are two possibilities that are believed to be nontoxic. To round out your nontoxic, toddler-proof plant room, consider the corn plant and coleus. Yucca filamentosa is an outdoor plant that can also be grown as a houseplant.