Story by Hugh Conlon
Oyama magnolia, indigenous to eastern Asia, is a deciduous 10-15 feet tall tree or shrub ideally suited for a small garden. Nodding, goblet-shaped, fragrant flowers bloom two to three weeks after the leaves emerge in April, thereby escaping injury from spring frosts.
In mid to late May, egg-shaped flower buds unfold with nine to 12 white tepals (sepals plus petals). At the center of 3-4-inch-wide blooms are the reddish brown stamens. Secondary flowers form intermittently through summer.
Autumn foliage turns pale yellow before abscising. Small 3-inch pink fruits form in late summer and split open to reveal bright orange red seeds.
This unique magnolia is limited to online specialty nurseries.
Quick Facts and Keys to Success
Common Name: Oyama magnolia
Botanical Name: Magnolia sieboldii
Varieties/cultivars: ‘Colossus’, a vigorous tetraploid selection, 10-20 feet tall.
Color: Creamy white flowers in late May
Type: Late spring flowering medium-to-large shrub
Size: 10-15 feet tall and wide
Exposure: Partial sunlight, full morning sun preferred; protect against strong winds.
When to Plant: Spring to late summer, either balled and burlapped (b&b) or container grown.
Soil: Prefers moist, humus-rich, slightly acidic soil.
Watering: Average heat and drought tolerance, mulch and deeply water during long dry spells.
When to Prune: The need for pruning is rare, but should be done within one month after flowering.
When to Fertilize: In early spring with a slow-release formulation.
In Your Landscape: An easy flowering magnolia that blooms for three to four weeks beginning in late May. Oyama begins flowering at an early age.