Calliandra haematocephala Seeds | Red Powderpuff
LATIN NAME: Calliandra haematocephala
COMMON NAME: Red Powderpuff
Plant Profile
Red powderpuff is a bushy evergreen shrub of the pea family, two to four metres tall and often as wide, with feathery, bipinnate leaves and a dense, rounded habit. The leaves are made of many small leaflets, which gives the plant a soft, ferny texture and a slightly shaggy look, and they fold slightly at dusk, which is a small daily event worth watching for.
The flowers are the point. Each head is a sphere of long, silky stamens, scarlet to deep pink, about five to seven centimetres across, with the actual petals reduced to almost nothing. The effect is a pom-pom of thread, and it is produced in repeated flushes through the year in a warm climate, with a peak in late winter and spring.
The fruit is a flat, brown pod that splits with a distinct snap when ripe, throwing its seed a metre or two. The seed is hard-coated and glossy, and it germinates readily after scarification. In the tropics the plant can become weedy along roadsides and in disturbed ground, though it is not usually considered a serious invader.
The species is native to Bolivia and possibly to adjacent parts of Peru and Brazil, and it has been planted across the tropics for so long that its natural range is uncertain. It is a plant of warm, humid, frost-free climates, and it will not survive more than a degree or two of frost.
Science & Biotechnology
The powderpuff flower is a pollination device built for hummingbirds and long-tongued butterflies. The stamens are the showy part, and the nectar is held at the base of a long, narrow tube, so that only a visitor with a long beak or proboscis can reach it. The plant is self-incompatible in many populations, which means it needs a second individual to set good seed, and the pollinator has to move between plants for the system to work.
The genus is large, with around two hundred species in the tropical Americas, and it sits in the Ingeae tribe of the mimosoid legumes, close to Inga and Albizia. The mimosoid group is known for its extrafloral nectaries, small glands on the leaf stalk that secrete sugar and attract ants, which then patrol the plant and deter herbivores. Calliandra has these glands, and the ant bodyguard service is part of its defence.
The seed biology is typical of the mimosoids. The seed coat is hard and water-impermeable, and germination follows scarification by fire, abrasion or passage through an animal. In cultivation, nicking the coat or soaking in hot water is the standard treatment, and untreated seed can remain dormant for years.
The chemistry of the genus has been studied mainly in the forage species, where condensed tannins and flavonoids are of interest. Red powderpuff itself is not a significant forage plant, and its main research value is ecological, as a model for hummingbird pollination and ant-plant defence in the neotropics.
Uses & Benefits
In the garden it is a specimen shrub for a warm, frost-free climate, grown for the flower heads and for the ferny foliage. It can be used as an informal hedge, as a background plant in a tropical border, or in a large container where it can be moved under cover for winter. It responds well to pruning after each flush of flower, and it can be kept to a compact two metres with annual cutting.
The flowers are long-lasting on the bush and are useful for cutting, though the stems are short. They attract hummingbirds in the Americas and sunbirds in Africa and Asia, and they are one of the most reliable nectar sources for butterflies in a tropical garden. The plant is also a larval host for several skipper butterflies.
It has a modest medicinal record in South America, where the bark and leaves are used in folk practice for inflammation and for skin complaints, and extracts have shown antimicrobial activity in vitro. There is no clinical evidence and no standardised preparation, and the plant should not be used as a medicine.
Ecologically, the shrub is a useful nectar source and a shelter plant, and its extrafloral nectaries support a small community of ants that patrol the leaves. In a garden managed for wildlife, that is a genuine benefit; in a pasture, the plant can spread and become a nuisance, and it is controlled as a weed in parts of Australia and the Pacific.
Growing from Seed
Scarify the seed by nicking the hard coat with a file, then soak in warm water overnight until it swells. Sow one centimetre deep in a loose, free-draining mix, and keep at twenty-two to twenty-eight degrees in bright light. Germination is usually two to four weeks, and fresh seed gives the best results.
Grow the seedlings on in full sun, in a rich but well-drained soil, and pinch out the growing tips to encourage a bushy shape. Plant out once the root has filled the pot and the risk of frost has passed, into a sheltered, sunny position. Water regularly through the first season, and feed lightly in spring. Prune after flowering to keep the plant compact and to prevent it from becoming leggy and bare at the base.
Our Take
Red powderpuff is one of the most generous flowering shrubs in the tropics: fast, free-flowering, insect-friendly and easy from seed, with a flower that looks manufactured rather than grown. It needs warmth and sun, and it needs a firm hand with the secateurs once a year, but beyond that it asks for nothing. Grow it where you sit in the evening, and the hummingbirds or sunbirds will find it.
Related Reading
More species in the same orbit as Red Powderpuff: