Sweetbay Magnolia

Size, growth and what to expect

Sweetbay magnolia starts fast and settles down. A first-year seedling grows 12 to 24 inches, rapid for a few years on good ground and poor to medium after that. Our growth estimator models it as a medium tree, roughly a foot and a half a year in its youth. In a garden it makes 15 to 35 feet tall and as wide, while wild trees in the Deep South reach 50 to 100 feet. Seedlings in the open have fruited at 6 years, and trees usually bear from about 10.

Creamy white flowers 2 to 3 inches across open from April into July. It usually sets some fruit every year, though yields are small. The fruit is a cone 1 to 2 inches long that splits in late summer to dangle scarlet seeds on threads for gray squirrels, turkeys, quail and songbirds. Swamp magnolia, its other name, reflects where it grows.

It grows wild along the Atlantic and Gulf coastal plains from Long Island south through New Jersey and southeastern Pennsylvania to south Florida and west to east Texas. Its wild sites are acid, poorly drained ground that floods in winter. Trees typically live about 80 to 130 years. The oldest in a Great Dismal Swamp study was 47 years old.

How to grow Sweetbay Magnolia

Sweetbay magnolia likes full sun or light shade and moist to wet soil, from garden ground to the boggy spot below a downspout. Soil should be acid to neutral; it yellows in limey ground. It makes a broad multi-stem clump, so plant it 10 feet from the house and 12 to 24 feet between trees.

Saplings ship potted. Magnolia roots are thick, fleshy and break easily, so plant in early spring as growth starts. Keep the root ball intact; set it in a hole twice its width, flare at grade, native soil, mulch off the stems, and stake only in a windy spot. Clean the oily red coat off seed and never let it dry; chill it damp for three months, sow in spring an inch deep, and cover with hardware cloth against mice.

Water weekly through the first two summers. Deer and rabbits can damage a young sweetbay, so cage or tube it for two or three years. Prune as little as possible; remove suckers for a single trunk or let them come for a clump.

A single sweetbay sets seed on its own, since pollen from one of its flowers can fertilize another flower on the same tree. Leaves may hang on through winter in the South and drop in the North; both are normal. Magnolia scale, a waxy bump on the twigs, is the main pest.