Native to eastern Asia and the eastern Americas north of the equator, the genus Magnolia includes approximately 80 species of trees and large shrubs. These plants generally like moist soils but will tolerate various conditions.
Magnolias grow in many soils and climates, but they thrive in moist soils in mixed deciduous-coniferous woodlands. They generally don't like dry or sterile soil.
Magnolias grow best in moist, rich soils with good drainage and high organic content. They prefer acidic to neutral soil but a few varieties, such as cucumber magnolia and sweetbay magnolia, can grow in alkaline soil. Organic mulch enhances soil acidity.
Various magnolia plants have different tolerance levels when it comes to soil. For example, pyramidal magnolia does not tolerate poorly drained soil, while sweetbay magnolia can grow in wet areas. Star magnolia varieties such as 'Royal Star,' 'Waterlily' and 'Centennial' tolerate many soil types.