Southern magnolia

About Southern magnolia

Southern magnolia is a large native evergreen tree of the Southeast with glossy leaves, rusty-fuzzy undersides and huge, fragrant, creamy-white flowers in late spring and early summer. Full-size trees reach 60-80 ft and shade out everything underneath, so semi-dwarf cultivars like 'Little Gem' suit most yards. NC State notes it often escapes from cultivation.

Zones 6-10 (NC State); 'Bracken's Brown Beauty' and 'Edith Bogue' are noted for winter hardiness.

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Plant container or balled-and-burlapped trees. Container trees can go in any time the ground can be worked, but fall is the best season in the South because roots keep growing through mild weather (Clemson). Dig the hole no deeper than the root ball and at least twice as wide, keep the top roots level with the soil, and mulch 2-4 inches without touching the trunk. Lower branches sweep the ground and can be pruned off for a tree shape. It drops leaves in spring and fall; NC State suggests mowing them and blowing them back under the canopy.

Soil

Rich, moist, well-drained soil, acidic to alkaline; very salt and wind tolerant, but not for swampy ground or long flooding (NC State).

Test the soil first. Loosen a wide planting area and mix 10-20 percent compost into the native soil you dig out; don't use uncomposted bark, and don't dig deeper than the root ball (Clemson).

Feeding

• Spring to early summer, after the tree is established, and only if a soil test or pale leaves and weak twig growth show a need: slow-release nitrogen fertilizer with a ratio near 3-1-1 or 3-1-2 (3-0-1 or 3-0-2 if the soil test shows enough phosphorus). Spread it evenly from just outside the trunk flare to the dripline and water it in. Clemson cites 2-4 lb of slow-release nitrogen per 1,000 sq ft per year, split into a spring and a late-summer feeding; follow your soil test.
• Late summer to early fall, the second half of the year's split feeding (only if a soil test calls for it): slow-release nitrogen fertilizer, same as spring. Apply the rest of the year's amount over the root zone and water in. Don't feed a drought-stressed tree in summer (Clemson).

First-year watering matters far more than fertilizer: water daily for the first 1-2 weeks, every 2-3 days until week 12, then weekly, using about 1-1.5 gallons per inch of trunk diameter, until the tree is established, roughly 1.5 years per inch of trunk (UMN). Don't count on rain unless it was over an inch. Mulch to prevent erosion under the canopy, and leave fallen leaves (mowed) under the tree to recycle nutrients (NC State). Too much fertilizer can burn roots and push soft growth that pests and cold injure (Clemson).

Harvest

Main bloom May-June with a few flowers through summer; no deadheading needed. Cone-like pods split in September-October to show red seeds that birds eat (NC State).

Varieties (7)

NC State documents these; several are semi-dwarf picks for home yards.

Pests to watch for

Magnolia scale, Scale insects

Diseases and problems

Sooty mold, Drought stress, Leaf scorch, Winter injury

In the kitchen

Pets: Not on the ASPCA's toxic plant list for dogs.