St. Mary Magnolia
Magnolia grandiflora 'St. Mary'
“'This is called a St. Mary magnolia.' Compact magnolia for the yard.”
Background
'Saint Mary' (syn. 'Glen St. Mary') was selected before 1930 at Glen St. Mary Nursery in Florida, a seedling from Joseph Vestal & Son of Little Rock, Arkansas (per Trees and Shrubs Online). It is a compact, free-flowering-from-youth selection of the southern magnolia, Magnolia grandiflora, the iconic evergreen of the southeastern US coastal plain. Monrovia lists it as a dwarf, compact pyramidal form suited to small landscapes. The UA arboretum notes the genus honors French botanist Pierre Magnol; it is Mississippi's state tree and Louisiana's state flower.
Distinguishing traits
Compact dense evergreen tree, about 20-25 ft tall and wide (much smaller than the species); glossy dark green wavy-edged leaves with conspicuous dark bronze-brown indumentum beneath. Large cup-shaped fragrant white flowers from an early age, mainly late spring and summer. The UA arboretum describes southern magnolia as a fast-growing evergreen tree of 60-90 feet with thick leathery leaves and large creamy-white fragrant spring flowers up to a foot across.
Desert care — zone 9b
- Chill hours
- n/a — ornamental
- Cold hardiness
- USDA 7-10; frost hardy to about 0°F. Queen Creek freezes are no problem.
- Heat tolerance
- Tolerates heat but prefers some afternoon shade in Phoenix; avoid reflected heat from walls and pavement.
- Water
- Moderate to high in Phoenix — not a desert-adapted tree. Deep, regular irrigation; keep soil evenly moist but not waterlogged. The UA arboretum rates water use as low, noting it handles well-drained soil and low water but grows leggy with fewer flowers if overwatered.
- Soil
- Deep, organically enriched, well-drained; prefers slightly acidic — Phoenix alkalinity can limit nutrient uptake, so mulch and amend.
- Sun exposure
- Full sun to partial shade; in Phoenix favor morning sun with afternoon shade.
Where to buy
- Monrovia
- Desert Horizon Nursery (Queen Creek, AZ)