Culture
Best grown in organically rich, neutral to slightly acidic, medium moisture, well-drained soils in full sun to part shade. Appreciates a root-zone mulch to help retain soil moisture. Also appreciates a location protected from strong winds, but avoid warm southern exposures which may promote premature bud opening in spring. Fleshy root system is easily damaged during transplanting, so it is best to select a landscape location carefully and leave this magnolia undisturbed once planted. Prune as needed immediately after flowering. Usually requires little pruning other than removal of dead or damaged branches.
Noteworthy Characteristics
The genus Magnolia consists of about 100 species (plus numerous additional hybrids and cultivars) of deciduous or evergreen trees and shrubs. Most plants feature large simple leaves and showy, sometimes fragrant flowers (yellow, white, pink or purple) which bloom in early spring before or while the leaves are emerging or in late spring to summer when trees are fully leaved.
Genus name honors Pierre Magnol, French botanist (1638-1715).
'Sunspire' is a yellow-flowered hybrid magnolia (M. ‘Woodsman’ x M. ‘Elizabeth’ which was registered in 1999 by Dr. August Kehr (1914-2001), geneticist and plant breeder, who registered a total of 31 magnolias in his lifetime. It is a columnar (very unusual for magnolias), deciduous, tree with fastigiate branching that typically matures to 20-25’ tall but to only 6-12’ wide. Deep yellow upright flowers bloom late in spring (late April – May). This cultivar has been voted to be the best yellow magnolia by the Magnolia Society members.
Problems
Potential disease problems include leaf spots, anthracnose, canker, dieback and powdery mildew. Potential insect problems include weevils, snails, scale, and thrips.
‘Sunspire’ blooms later than many of the magnolias and its flowers are very unlikely to suffer frost damage in spring.
Uses
Excellent specimen or accent for sunny areas in the landscape where spring flowers can be appreciated. Small shade tree.
'Sunspire will fit into narrow spaces in the landscape due to its columnar form.