Hymenosporum flavum (Hook.) F.Muell.

Size and Growth Habit

Hymenosporum flavum (Hook.) F.Muell. is a semi-deciduous tree that reaches up to 25 m (82 ft) in height, with a trunk diameter at breast height (DBH) of up to 45 cm (18 in).

Leaf Appearance

Its leaves are simple, obovate, and arranged alternately; they are glossy green on the upper surface and lighter on the lower surface.

Leaf Arrangement and Dimensions

The leaves grow up to 13 cm (5.1 in) long by 4.5 cm (1.8 in) wide, and are clustered near the ends of branches in pseudo-whorls.

Flower Size and Fragrance

The flowers of this species are very fragrant, quite large, and measure around 40 mm (1.6 in) in diameter, with a floral tube up to 28 mm (1.1 in) long.

Initial Flower Stage

When flowers first open, they are functionally male, and colored white with faint lemon tinges.

Floral Development Process

Over approximately 5 days, the stigma develops and the stamens curl inward.

Mature Flower Stage

At the same time, the flower’s color deepens; when the flower becomes fully functionally female, it is golden yellow with red or purple track lines in the throat.

Fruit Characteristics

The fruit is a dehiscent two-chambered capsule, black to brown in color, densely hairy, and about 35 mm (1.4 in) both wide and long.

Seed Features

The numerous seeds are around 7 mm (0.28 in) long with a 4 mm (0.16 in) wing, and are stacked together to fill each capsule chamber.

Native Distribution

The native range of Hymenosporum flavum extends from New Guinea south through coastal Queensland to northeastern New South Wales.

Habitat Preferences

It grows in rainforest or wet sclerophyll forest on a variety of soil types.

Phenology

Flowering occurs from early spring to early summer, and fruits ripen around May.

Cultivated Size

Commonly called native frangipani, this species is widely cultivated. Cultivated specimens usually grow to around 8 meters in height, though wild individuals in rainforest can reach over 20 meters tall.

Light Requirements

It can be grown in shaded locations, but produces the most flowers when grown in full sun.

Common Planting Locations

In Australia, it is commonly planted along suburban streets, shopping boulevards, and walkways between tall buildings.

Soil Adaptability

It prefers well-drained soil with high organic content, but is highly adaptable to other conditions.

Cold Tolerance

Very young seedlings are easily killed by frost, but if they are kept in a sheltered position until they reach 1–1.5 meters in height, they will grow well in cooler areas, as long as they have access to water during hot, dry periods.

Flammability Rating

Hymenosporum flavum is included on the Tasmanian Fire Service's list of low flammability plants, meaning it is suitable for planting within a building protection zone.