Bidibid

Botanical name: Acaena saccaticupula
Synonyms: None
Common name(s): Bidibid, Piripiri

About:
An attractive alpine groundcover forming dense, spreading mats of dull green to bluish-green foliage. Acaena saccaticupula is particularly distinctive when flowering, producing rounded red to pink flower heads held above the foliage on sturdy reddish stems. These are followed by characteristic hooked burr-like fruits that assist with dispersal.

Natural habitat:
Montane to alpine environments, particularly snow tussock grasslands, herbfields, fellfields and other open high-country habitats. It occurs in exposed mountain environments, including areas subject to prolonged winter snow cover.

Growing environment:
Frost, sun, wind and free-draining tolerant. Best suited to cool, open situations with excellent drainage. Once established, it is well adapted to exposed alpine conditions and relatively lean soils.

Endemic distribution:
Endemic to New Zealand’s South Island, principally east of the Southern Alps from Marlborough south through Canterbury to Otago.

Height:
Approximately 5 cm tall, with flowering stems rising above the foliage.

Width:
Spreading mats may reach approximately 1 m across.

Flowering:
December–January. Rounded red to pink flower heads are carried on stout reddish stems above the foliage.

Fruiting:
January–March. Develops pale brown burr-like seed heads armed with short hooked spines that readily attach to passing animals.

Uses:
• Alpine and rock gardens
• Low-growing groundcover
• Scree and gravel gardens
• Erosion control on suitable slopes
• Exposed high-country planting
• Texture planting
• Specialist native plant collections

Appearance:
Growth habit:
A very low, stoloniferous perennial herb forming dense spreading mats. Creeping stems extend across the ground and root at the nodes, allowing individual plants to gradually colonise surrounding open ground.

Leaves:
Leaves are finely divided, typically into 9–15 toothed leaflets. The foliage ranges from dull green to bluish-green, sometimes developing attractive pinkish or reddish tinges around the margins, particularly under cold or exposed conditions.

Flowers:
Numerous tiny flowers are grouped together into conspicuous rounded flower heads. These are predominantly red to pink and are carried above the foliage on sturdy reddish flowering stems.

Fruit:
The flowers develop into distinctive compact, somewhat cone-shaped burr-like seed heads. Individual fruits bear short hooked spines that become pale brown as they mature.

Ecology:
An alpine mat-forming species adapted to exposed, cold and windswept environments. Its creeping stems help stabilise loose surface material while allowing the plant to spread through gaps between grasses, herbs and rocks.

The hooked fruits are adapted for external animal dispersal, readily attaching to fur or feathers and being transported away from the parent plant.

Associated habitats:
Snow tussock grassland, alpine herbfield, fellfield, rocky slopes, scree margins and other open montane to alpine vegetation.

It commonly occupies sites amongst low alpine herbs, tussocks and other vegetation adapted to cold, exposed South Island mountain environments.

How to grow:
Grow in full sun in exceptionally free-draining soil. A gritty or gravel-rich soil resembling its natural alpine habitat is ideal.

Avoid rich, permanently wet or poorly aerated soils. Plants are particularly suitable for rockeries, alpine troughs, gravel gardens and exposed slopes where their creeping stems can spread naturally.

Once established, little maintenance is required. Excessive competition from taller or vigorous plants should be controlled to prevent the low mats from being overwhelmed.

Propagation:
Propagation is by division or seed.

Established mats can be divided by removing rooted sections of creeping stem and immediately replanting them into free-draining soil.

Seed can be collected from mature burrs and sown into a fine, gritty propagation medium. Cool conditions that approximate the species’ natural alpine environment are preferable.

Cultural use:
No specific traditional Māori uses are widely documented for Acaena saccaticupula. The names piripiri and bidibid are widely applied to members of Acaena, referring particularly to their characteristic hooked fruits that cling readily to clothing, fur and feathers.

Garden value:
An excellent specialist groundcover for alpine, rock and gravel gardens. Its extremely low growth, spreading habit and finely textured blue-green foliage provide year-round interest, while the reddish flowering stems and rounded red-pink flower heads add a particularly attractive seasonal display.

It is especially valuable where a genuinely low-growing New Zealand alpine species is required for exposed, sunny and sharply drained positions.