Southern magnolia
Magnolia grandiflora
also called bull bay, evergreen magnolia
The South in one tree: huge glossy evergreen leaves backed in rust felt, and dinner-plate white flowers all summer with a lemon perfume that carries across the yard.
- Type
- Tree · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green · Bronze, red and brown
- Flower color
- White
- Sunlight
- Full sun to part shade
- Watering
- Moderate; mulch wide and let its own dropped leaves lie
- Soil
- Rich, acid, moist, well-drained
- Feeding
- All-purpose balanced
- USDA zones
- 6b–10a
- Frost tolerant
- Yes
- Plant out
- 14 days before the last spring frost
- Plant spacing
- 32 ft 10 in
- In-row spacing
- 26 ft 3 in
- Between rows
- 39 ft 4 in
- Square-foot density
- Not suited to SFG
- Root system
- A fine surface mat, and nothing below it
- Working depth
- 8–20 in
- Spread
- 39–59 ft across, about 1–1.5× the width of the plant
- Shallowest pot
- 16 in of soil
Hair-fine roots in a shallow felt, with no deep anchor to fall back on. It cannot chase water, so it is the first casualty of a drought and the first thing killed by a hoe. Mulch it, never cultivate around it, and never let it go dry in its first two summers.
Wide, ropey, shallow roots and a permanent litter of heavy leaves, so very little grows underneath a magnolia. Take the ground under it as a mulched bed rather than a border, and never cultivate it.
Figures recorded for Southern magnolia itself. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- When
- Not harvested, though the flowers and seed cones cut beautifully. Glossy branches for the mantel in December.
- What to look for
- For the vase, a flower just opening from the candle stage; it lasts a single perfumed day indoors and browns at a touch.
- How to harvest
- Cut foliage branches back to a side shoot, taking them from inside the skirt so the wall of green stays whole. Float a just-open flower in a wide bowl and accept its one-day reign.
- How often
- A December cutting for the house; otherwise let the skirt grow to the ground and rake nothing.
- Storing the crop
- Cut magnolia foliage dries bronze and lasts for months in arrangements, which is why florists sell it by the pound.
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Hoverfly SyrphidaeHunts Scale insects
Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.
- Ladybird (lady beetle) CoccinellidaeHunts Scale insects
The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.
It sheds old leaves all year, and grass will not grow under it anyway, so the honest planting is a skirt of branches to the ground hiding its own leaf litter: self-mulching, zero raking. 'Little Gem' fits a small yard; the species does not.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com