Introduction

Star Magnolia is the hardiest of the Magnolias. It is a small tree or large shrub, 15 to 20 feet tall with a 10 to 15-foot spread. Typically branching close to the ground, the multi-stemmed form develops with a dense head of foliage. Star Magnolia makes a wonderful patio, lawn specimen or accent tree. Lower foliage can be removed to show off the trunk and to create more of a tree-form. Otherwise, the persistent lower branches and oval to round form lend a "large bush" look to the plant. When planted against a dark background, the branching pattern and light gray trunk will show off nicely, particularly when lit up at night. The leafless winter silhouette looks great shadowed on a wall by a spotlight at night. The white flowers are produced in spring before the leaves appear, even on young plants. Flowers are usually not as sensitive to cold as Saucer Magnolia, but they can still be injured if cold weather arrives during flowering.

General Information

Scientific name: Magnolia kobus var. stellata

Pronunciation: mag-NO-lee-uh KOE-bus variety stell-AY-tuh

Common name(s): Star Magnolia

Family: Magnoliaceae

USDA hardiness zones: 5A through 8B (Fig. 2)

Origin: not native to North America

Invasive potential: little invasive potential

Uses: deck or patio; specimen; container or planter

Availability: not native to North America

Description

Height: 15 to 20 feet

Spread: 10 to 15 feet

Crown uniformity: symmetrical

Crown shape: round

Crown density: moderate

Growth rate: slow

Texture: medium

Foliage

Leaf arrangement: alternate (Fig. 3)

Leaf type: simple

Leaf margin: entire

Leaf shape: oblong, obovate

Leaf venation: pinnate, brachidodrome

Leaf type and persistence: deciduous

Leaf blade length: 2 to 4 inches

Leaf color: green

Fall color: yellow, copper

Fall characteristic: not showy

Flower

Flower color: white/cream/gray

Flower characteristics: very showy

Fruit

Fruit shape: elongated, irregular

Fruit length: 1 to 3 inches

Fruit covering: dry or hard

Fruit color: brown

Fruit characteristics: does not attract wildlife; not showy; fruit/leaves not a litter problem

Trunk and Branches

Trunk/bark/branches: branches droop; not showy; typically multi-trunked; thorns

Pruning requirement: little required

Breakage: resistant

Current year twig color: brown

Current year twig thickness: thin, medium

Wood specific gravity: unknown

Culture

Light requirement: full sun, partial sun or partial shade

Soil tolerances: clay; sand; loam; acidic; slightly alkaline; well-drained

Drought tolerance: moderate

Aerosol salt tolerance: none

Other

Roots: not a problem

Winter interest: yes

Outstanding tree: no

Ozone sensitivity: tolerant

Verticillium wilt susceptibility: susceptible

Pest resistance: resistant to pests/diseases

Use and Management

Star Magnolia is intolerant of root competition or dryness, and plants grow slowly, perhaps one foot per year. Plant in the full sun in a rich, porous and slightly acid soil. It is hard to transplant successfully and in the north should be moved balled and burlapped when actively growing. In USDA hardiness zones 7 and 8, transplant in late winter while the plants are still dormant or plant from containers at any time.

There are a few cultivars: `Centennial' - some pink in petals; `Jane Platt' - new, superior type with many pink petals when opening; `Keiskei' - flowers purplish on the outside; `Rosea' (Pink Star Magnolia) - pale pink flowers; `Rubra' (Red Star Magnolia) - purplish flowers, darker than `Rosea'; `Waterlily' - pink flower buds, white flowers, flowers larger with narrower petals. The "Little Girl Hybrids" have an upright habit and flower later than the species, thus avoiding frost injury in most years. They include `Ann', `Betty', `Jane', `Judy' `Randy', `Ricki' and `Susan'.

Pests

Basically trouble free although scales of various types may infest twigs and leaves. Magnolia scale is the most common scale and can be one half-inch-across. Overwintering scales can usually be controlled with horticultural oil.

Tulip-Poplar weevil (sassafras weevil) feeds as a leaf miner when young and chews holes in the leaves as an adult.

Diseases

None particularly troublesome. Magnolia may be subject to leaf spots, blights, scabs, and black mildews caused by a large number of fungi or bacterium. Leaf spots rarely require chemical controls. Rake up and dispose of infected leaves.

Canker diseases will kill branches. Cankers on branches can be pruned out. Keep trees healthy with regular fertilization and by watering in dry weather.

Verticillium wilt may cause death of a few branches or may kill the tree. Prune out dead branches and fertilize regularly.