Another fragrant early bloomer is the star magnolia (M. stellata, Zone 4). Star magnolias can be small trees or large shrubs, making them suitable for the smaller garden. Each flower is made up of 12 to 40 narrow white or pale pink tepals. ‘Centennial’, an introduction from the Arnold Arboretum, is more tall than broad and reaches 25 feet tall at maturity. This wonderful small tree deservedly received the Pennsylvania Horticultural Society Gold Medal, given to trees and shrubs that have outstanding ornamental attributes. ‘Rosea’ is soft pink in flower. ‘Royal Star’ opens pink and fades to white.
Magnolia x loebneri (Zone 4) is similar to the star magnolia—one of the parents of this hybrid—but generally flowers slightly later. ‘Leonard Messel’ bears fragrant, soft pink flowers that are larger than those of a star magnolia. At maturity, it will reach up to 15 feet tall and can be treated as a large shrub or small tree. ‘Merrill’ is also fragrant and has white flowers.
The Little Girl hybrids (Zone 5) are the result of breeding work by the U.S. National Arboretum in the late 1950s, using varieties of M. liliiflora and M. stellata as parents. In all, the arboretum released eight cultivars: ‘Ann’, ‘Betty’, ‘Jane’, ‘Judy’, ‘Pinkie’, ‘Randy’, ‘Ricki’, and ‘Susan’. These hybrids reach from 8 to 15 feet tall with an equal spread. The flower colors range from deep pink to a deep purple. They flower in midspring and therefore are less likely to be damaged by freezing weather.
Similar in color but larger in stature to the Little Girls are ‘Galaxy’ and ‘Spectrum’, both hardy to Zone 6. ‘Galaxy’ is a pyramidal tree that reaches 30 feet at maturity. The large flowers are deep pink-purple. ‘Spectrum’ has a broader habit and darker flowers than ‘Galaxy’. I have seen ‘Galaxy’ used effectively as a street tree.
The largest of the magnolias for North American gardens is the cucumber tree magnolia (M. acuminata, Zone 4). It is native from eastern Canada to Florida and can reach over 100 feet tall at maturity. It produces relatively small greenish yellow flowers that are often found high up in the tree and are hard to see from the ground.