Species: Magnolia liliiflora
Common name: Lily magnolia, Japanese magnolia, Mulan magnolia, purple magnolia, red magnolia, tulip magnolia
The Magnolia liliiflora (lily magnolia) is a large deciduous shrub (or small tree) that sports profuse pink or reddish-purple blossoms in April and early May, just before the leaves appear. As one of the smaller magnolias, it is popular for informal screens or hedges and as a specimen plant grown for its spring flower display.
Lily magnolia grows to a mature height of 8 to 12 feet with a similar spread. It has a compact, rounded form and produces a massive display of lily-shaped pink or reddish-purple flowers with six or seven petals, with each petal 3 to 4 inches long. The flowers are sometimes followed by cone-shaped purple or brown fruit, called follicles. As with other magnolia species, pollination is facilitated by beetles. The shrub’s dark green elliptical-shaped leaves appear as its flowers fade. Its fall foliage is not showy.
|Plant type||Deciduous shrub|
|Mature size||8 to 12 feet tall and wide|
|Sun exposure||Full sun to part sun|
|Soil type||Rich, well-drained|
|Soil pH||5.8 to 6.8|
|Hardiness zones||5 to 10, depending on variety|
|Native area||China, Japan|
|Water||Once a week|
Water the shrub regularly throughout the year for the first few years, and cover the root zone with mulch to balance out soil moisture levels and temperatures. Once established, lily magnolia is moderately tolerant of dry conditions.
How to grow
Lily magnolia is most often grown as a specimen or accent plant in sunny areas. It’s also good for group plantings or as an informal hedge or screen. It is moderately drought-tolerant once the roots have had a chance to firmly anchor themselves after several years.
You can propagate this magnolia by taking cuttings or planting the seeds. If you have planted a cultivated variety, the plants resulting from the seeds may be different from the parent plant.
For best flowering, lily magnolia requires a site with full sun, though it also grows adequately in partial shade.
The plant does best in moist, rich soils that are slightly acidic and well-drained. Heavy soils should be amended with peat moss or compost before planting.
Temperature and humidity
Lily magnolia is best planted in a semi-sheltered area that is protected from strong winds and cold temperatures. Also, avoid southern exposures where the buds may open too early in spring.
Lily magnolias do not need fertilizer when they are planted. Afterward, they benefit from a spring feeding of slow-release fertilizer, when the flower buds begin to develop.
Magnolia liliflora ‘Nigra’: Darker purple flowers than the species form; hardiness zones 5 to 9
Magnolia liliflora ‘O’Neil’: Grows to 15 feet with dark purple flowers; hardiness zones 6 to 9
Magnolia liliflora ‘Gracilis’: Not quite as wide as the species, with narrower leaves; hardiness zones 5 to 9
In addition to these popular cultivars, ‘Nigra’ is often crossed with other Magnolia species to produce new hybrids. For example, the U.S. National Arboretum created eight different varieties by crossing ‘Nigra’ with Magnolia stellata ‘Rosea.’ They are collectively called “The Girls” since they were given female names: ‘Ann,’ ‘Betty,’ ‘Jane,’ ‘Judy,’ ‘Pinkie,’ ‘Randy’, ‘Ricki,’ and ‘Susan.’ Another is ‘Star Wars,’ a hybrid of M. campbellii and M. liliiflora, with large, rosy-pink flowers up to 11 inches across.
Pests and diseases
Lily magnolia is a relatively problem-free shrub, and those problems that do occur are rarely life-threatening.
- Magnolia scale insects (Neolecanium cornuparvum) suck out sap from the stems. Encourage ladybugs to visit your garden, as they will snack on the scales and help remedy the problem to some degree. Horticultural and dormant oils can be used at different stages in the life cycle, though they will not be so effective against adults that have formed a wax barrier on their bodies.
- Black sooty mold can form on plants that are infested with the magnolia scale. They drop a sugary substance called honeydew that the mold grows on. Control the scale insects to help prevent mold.
- Powdery mildew is another fungal problem that can crop up, especially in humid conditions, but it rarely kills the plant. To reduce powdery mildew, prune to improve air circulation. Keep the area around the tree free of debris. Spraying the shrub with water early in the day may help dislodge mold spores. Fungicides applied early in the season can also prevent mildew.
Magnolias generally do not respond well to severe pruning, but when the shrub becomes overgrown or when there are dead or damaged branches, prune it immediately after it flowers. If you prune too late, it will reduce flowering the following spring.