Coral Broom

Botanical name: Carmichaelia crassicaulis subsp. crassicaulis
Synonyms: Corallospartium crassicaule, Corallospartium crassicaule var. crassicaule
Common name(s): Coral broom

About:
A distinctive upland native broom forming a rigid shrub with thick grooved green branches that resemble coral. Mature plants are almost leafless and produce clusters of small cream to pale purple pea flowers. This unusual species is one of New Zealand’s most recognisable brooms and is naturally restricted to inland eastern South Island habitats.

Natural habitat:
Montane and subalpine tussock grasslands, shrublands, rocky slopes and open upland habitats.

Growing environment:
Prefers full sun and well-drained soils in cool, dry climates. Tolerates frost, drought and exposed conditions but dislikes humid environments and poor drainage.

Endemic distribution:
Endemic to New Zealand. Found east of the Main Divide in Marlborough, Canterbury and Otago.

Height:
Up to 2 m tall

Width:
Typically 1–2 m wide

Flowering:
December – January

Fruiting:
March – May

Uses:

• Native shrubland restoration
• Dryland revegetation
• Rock gardens
• Alpine gardens
• Rare plant conservation
• Habitat restoration
• Feature planting

Appearance:

Growth habit:
Rigid upright shrub with stout erect branches and a sparingly branched structure.

Leaves:
Juvenile plants bear small rounded leaves, while adult plants become almost entirely leafless with leaves reduced or absent.

Stems:
Thick yellow-green branches deeply grooved with numerous parallel furrows lined with white hairs. Young branchlets are flattened and densely covered in soft white hairs.

Flowers:
Small cream to pale purple pea flowers with darker purple markings, produced in dense clusters along the stems.

Fruit:
Produces small rounded hairy seed pods, usually containing a single hard yellow seed.

Ecology:
A specialised species of dry inland grassland and shrubland ecosystems. Like other native brooms, it is a nitrogen-fixing plant that contributes to soil fertility and supports native insect life.

Associated habitats:
Montane tussock grassland, subalpine shrubland, rocky outcrops, scree margins and dry inland basins.

How to grow:
Plant in full sun in very well-drained soil. Avoid humid conditions and minimise root disturbance after planting, as established plants dislike being moved. Best suited to dry inland climates.

Propagation:
Readily grown from fresh seed. Semi-hardwood cuttings can be successful but are generally more difficult to strike.

Cultural use:
Part of New Zealand’s unique indigenous broom flora and a characteristic species of the eastern South Island’s dry inland landscapes.

Garden value:
An outstanding architectural shrub valued for its unusual coral-like branching, year-round structure and ability to thrive in harsh dry conditions. Particularly effective in rock gardens, alpine plantings and specialist native collections.