Magnolia odora Seeds | Odour Magnolia
LATIN NAME: Magnolia odora
COMMON NAME: Odour Magnolia
Plant Profile
The odour magnolia belongs to the evergreen, axillary-flowered group that botanists long kept as the genus Michelia and have since folded back into Magnolia. It is a small to medium tree, eight to fifteen metres in the wild, with a dense crown of leathery, obovate leaves eight to fourteen centimetres long, dark green and glossy above and paler beneath, with a wavy margin and a blunt tip. The young growth is covered in a fine brown down, and the buds are enclosed in hairy scales that split as the shoot extends. The bark is grey and smooth, and the wood is pale, close-grained and faintly aromatic.
The flowers are the point of the tree. They open singly in the leaf axils rather than at the ends of the shoots, so they sit close against the branches and are easy to miss until the scent gives them away. Each has nine tepals, creamy white to pale yellow, and a heavy, fruity fragrance that carries a long way on still, humid evenings. Flowering runs from late spring into summer on the main flush, with sporadic flowers produced on new growth into autumn. The fruit is an aggregate of follicles that splits in autumn to reveal seed with a bright orange-red aril, and those seeds are taken by birds. The species is native to the hill forests of southern China and northern Vietnam, where it grows in deep, acid, humus-rich soil in moist valleys, and it is uncommon throughout its range and rare in cultivation.
Science & Biotechnology
The flower scent has been analysed in some detail, and it is dominated by linalool, methyl benzoate and phenylethanol, a combination that reads as sweet, fruity and slightly citrus, and that is strongest in the evening. The chemistry is consistent with beetle pollination, which is the ancestral condition in the family: the flowers offer pollen and scent rather than nectar, and the beetles use the floral chamber as a shelter while they feed. The extended flowering period, unusual among magnolias, is thought to spread the risk of pollination failure in the wet, cloudy conditions of its native forests.
The species also matters in the ongoing reorganisation of magnolia taxonomy. Molecular phylogenies have shown that Michelia is nested within Magnolia, and that the evergreen, axillary-flowered species form a group inside the genus rather than a separate one, which is why the name has changed. Work on the family’s seed biology has shown that the seed is recalcitrant: the orange aril is rich in lipids and the embryo has no dormancy, so the seed cannot be dried or stored and must be sown within days of ripening. That fact, combined with the species’ rarity, explains why it is so seldom offered. Conservation assessments place it among the threatened magnolias of the region, and ex situ collections are few.
Uses & Benefits
As a garden tree the odour magnolia is grown for scent and evergreen structure, and it is best placed where the evening air will carry the fragrance to a terrace or a doorway. It is slower and less showy than the deciduous magnolias, and it does not flower young, so it suits a collector or a patient gardener rather than someone wanting immediate effect. In a warm, sheltered garden it makes a handsome small specimen with clean, dark foliage and a long, modest flowering season. The flowers last well in water and are used in southern China as a fragrant cut flower, sold in small bunches at markets.
There is a nomenclature trap to flag. Magnolia bark in Chinese medicine, Hou Po, comes from Magnolia officinalis and its close relative M. officinalis var. biloba, and the bark of evergreen michelia species is not a substitute. Several members of the group have aromatic bark, and substitutions have been recorded in the trade, but the chemistry is different and the medicinal dose is not transferable. The wood of Magnolia odora is used locally for light construction and for furniture, and the tree is sometimes planted around villages for its scent. It has no significant commercial plantation presence.
Growing from Seed
Sow the seed as soon as the aril is removed, because it will not keep. Rub the orange coating off in water, and sow into a mix of leaf mould, coarse sand and loam, covering the seed by its own depth. Keep the tray at twenty-two to twenty-five degrees, in bright filtered light, and hold humidity with a clear lid, ventilating daily. Germination takes six to twelve weeks and is uneven. Do not let the mix dry out at any point, and do not store seed in a refrigerator in the hope of saving it for spring; it will be dead by then.
Prick the seedlings out into deep pots once the first true leaves have hardened, and grow them on in a shaded frame, moving them gradually into more light in their second year. Plant out in spring into deep, acid, humus-rich soil in a sheltered position, with shade from strong afternoon sun while the tree is young. Mulch with leaf mould each autumn and keep the ground clear of competition. The species is frost tender below about minus five degrees, so in cool climates it needs a conservatory or a walled garden. Water steadily through the first three summers.
Our Take
A tree for the collector and the patient, grown for the scent rather than the display. Fresh seed and a frost-free site are the two things that decide whether it succeeds.
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