These same species also extend at least into zone 9. These two species will be the focus on breeding for more cold hardy evergreen Magnoliaceae . Plant size and growth habit is extremely variable within the evergreen members of the Magnoliaceae. Plants like Magnolia grandiflora can easily grow to be 60 feet tall with equal or greater spread. Smaller members of this family are small shrubs.
Growth habit can range from wide spreading to narrowly upright.
Mangletia yunnanensis has a very upright, formal growth habit and appears to be an ideal candidate for breeding. I have been successful in crossing Magnolia grandiflora 'Little Gem' with this species. The reciprocal cross has not been successful. I have tried crossing many evergreen and deciduous species onto Mangletia yunn . Leaf form varies widely within the evergreen members of the Magnoliaceae.