Dioon (Gum) Palm Tree - Dioon spinulosum Giant Dioon is technically a cycad of pre-historical origin, and the Dioon palm tree can grow up to 1 ½ ft. in diameter with a Dioon trunk growing twelve feet tall. Growing palms can also be done indoors. You can have a palm inside your home or workplace to add a tropical really feel and develop elegance. When increasing them indoors, you should stay away f