You Will Get 10 Seeds Paulownia Kawakamii Sapphire Dragon Tree. This tree grows extremely rapidly, and it can reach heights of 40’+.. It gets large clusters of purple flowers in spring, and make quite the show.. The leaves are heart shaped, and are extremely large on young trees, but they do get smaller as the trees mature.. These trees are hardy to zone 6 and are extremely beautiful, and still fairly rare and uncommon.