Small-Leaved Bidibidi
Acaena microphylla
This native plant, known as Small-leaved Bidibidi (scientific name: Acaena microphylla ), is a hardy, mat-forming perennial endemic to New Zealand. It is cherished for its dense, bronze-tinged foliage and distinctive reddish burrs. This comprehensive guide provides detailed information on its habitat, cultivation, and ecological importance. Understanding this plant contributes to the appreciation of our rich biodiversity and heritage, and supports conservation efforts for native ground cover .
Plant Description
Identification and Physical Characteristics
Acaena microphylla is characterized by its small, delicate, fern-like, pinnate leaves, which often display an attractive bronze tint, especially when young or exposed to full sun. The leaves can grow up to 3 cm (1.2 inches) long and have serrated edges. It forms dense, spreading mats with reddish-brown stems that root at the nodes. In summer, the plant produces inconspicuous greenish or white flowers on tiny purple spikes. These are followed by its most striking feature: distinctive, attractive reddish burrs, approximately 2.5 cm (1 inch) in length, covered in spines. These burrs are crucial for seed dispersal, readily clinging to animals and clothing.
Quick Facts
| Scientific Name | Acaena microphylla |
|---|---|
| Height | 5-10 cm (Ground Cover) |
| Spread | Up to 1 m |
| Water Needs | Low to Moderate |
| Light | Full Sun to Partial Shade |
| Frost Tolerance | High |
| Salt Tolerance | Moderate |
| Growth Rate | Moderate to Fast |
| Lifespan | Perennial |
Climate Best Suited to
Small-leaved Bidibidi is highly adaptable, found across both the North and South Islands of New Zealand, from coastal areas to subalpine regions up to 1300 meters above sea level. It thrives in cool, moist conditions with good drainage. Its hardiness allows it to tolerate a wide spectrum of climatic conditions, including high frost. This versatility makes it suitable for various landscapes, from sunny open sites to dappled forest edges.
Regional Suitability
| City | Climate Suitability |
|---|---|
| Auckland | Suitable |
| Wellington | Highly Suitable |
| Christchurch | Highly Suitable |
| Dunedin | Highly Suitable |
| Nelson | Highly Suitable |
| Invercargill | Highly Suitable |
Plant Habitat
Natural Occurrence and Ecology
The natural habitat of Acaena microphylla is diverse, ranging from coastal areas to subalpine zones. It is frequently found in disturbed areas such as roadsides, riverbeds, grasslands, and river terraces. It thrives in open, well-drained locations, often establishing in sites with good sunlight exposure. Its mat-forming habit allows it to effectively colonize bare ground, acting as a pioneer species in various ecosystems across New Zealand.
Growing Requirements
Soil Requirements
Prefers well-drained soil; tolerates various types, including sandy or loam soils that maintain some moisture.
- Well-drained soil
- Sandy or loam soils
- Tolerates poor soil
Light Requirements
Flourishes in full sun to partial shade; sunny positions enhance bronze foliage.
- Full sun for colour
- Partial shade tolerated
- Minimum 50% sun
Water Requirements
Low to moderate water needs; prefers consistent moisture but is relatively drought-tolerant once established.
- Water when soil dry
- Drought resistant
- Avoid waterlogging
Planting and Establishing
Establishment Guidance
Establishing Small-leaved Bidibidi is straightforward due to its vigorous growth and adaptability. It is an excellent choice for groundcover, effectively suppressing weeds and controlling erosion on banks and slopes. Plant in spring or autumn. Dig a hole twice the width of the root ball and backfill with well-draining soil. Space plants 30-40 cm apart to allow for its rapid spreading habit. Water well after planting and maintain moisture for the first few weeks. Once established, it quickly forms a dense, low-maintenance mat. It can also be propagated easily from fresh seeds or by dividing existing mats.
Ecological Role
Biodiversity and Ecosystem Impact
Acaena microphylla plays a vital ecological role in New Zealand's natural landscapes. Its mat-forming habit helps stabilize soil, preventing erosion, particularly in disturbed areas and on slopes. The plant's dense foliage provides effective weed suppression, allowing other native species to establish. Its distinctive spiny burrs are crucial for seed dispersal, readily attaching to animals, birds, and even clothing, thus facilitating the plant's spread to new areas. It also provides ground-level habitat and foraging opportunities for various invertebrates and small native fauna.
Uses & Significance
Garden Uses
Widely used as an ornamental groundcover in gardens, rock gardens, and on banks. Its bronze foliage adds unique colour and texture.
- Groundcover
- Erosion control
- Weed suppression
Ecological Value
A key pioneer species for ecological restoration. Its burrs aid in seed dispersal, supporting natural regeneration and providing habitat for small fauna.
- Soil stabilization
- Habitat provision
- Biodiversity support
Landscaping Uses
In landscaping, it is used to create textural groundcover, especially in rockeries, between paving stones, or on slopes. Its ability to tolerate light foot traffic makes it versatile. The bronze coloration provides excellent contrast in mixed plantings.
Seasonal Care Calendar
Spring
Active growth period. Monitor for any invasive weeds. Light fertilization can be applied.
- Light weeding
- Spring mulching
Summer
Fruiting season; burrs develop and ripen. Ensure consistent moisture during dry spells.
- Occasional watering
- Burr management (if needed)
Autumn
Ideal time for dividing large clumps or establishing new plantings. Foliage often intensifies in colour.
- Divide clumps
- Prepare new sites
Winter
Growth slows. The plant is evergreen and maintains its foliage. Minimal care is needed.
- Minimal care
- Check drainage
When to Prune and How Much
Small-leaved Bidibidi requires minimal pruning. It can be trimmed along the edges to control spread or to remove any leggy growth.
- Light trimming for shape
- Remove unwanted spread
If the burrs are a nuisance in high-traffic areas, they can be mown or clipped off in early summer before they fully mature.
How to Grow Small-Leaved Bidibidi
Growing Small-leaved Bidibidi ( Acaena microphylla ) is a highly rewarding experience due to its hardiness, attractive foliage, and rapid growth as a groundcover. It is particularly valued for its ability to form dense, weed-suppressing mats, making it an excellent choice for erosion control on banks and slopes, or as an ornamental feature in rock gardens and between paving stones. This plant readily roots at the nodes, allowing it to spread naturally and cover large areas effectively. Its adaptability to various light and soil conditions further enhances its appeal to both novice and experienced gardeners seeking a low-maintenance yet visually appealing native plant.
From Cuttings
Cuttings are an extremely effective and easy method for propagating Small-leaved Bidibidi. Stems that have rooted at the nodes are ideal.
Take semi-hardwood cuttings in late summer or autumn for the best results.
- Select healthy, vigorous stems, ideally those that have already formed aerial roots.
- Cut sections approximately 10-15 cm long, ensuring each cutting has several leaf nodes.
- Remove the lower leaves and lightly wound the base. Rooting hormone is optional but can speed up the process.
- Plant into a well-draining potting mix, such as a blend of sand and peat.
- Keep in a warm, sheltered spot with indirect light and maintain consistent moisture without waterlogging.
- Roots should establish within a few weeks, after which the new plants can be hardened off and planted in their final location.
From Seed
Seed propagation is also a successful method, especially if you need to produce a large number of plants for a restoration project.
Collect the dry, reddish burrs in late summer or autumn.
- Remove the barbed spines from the burrs to extract the seeds. Wear gloves to protect your hands.
- A cold stratification period of 4-6 weeks can significantly improve germination rates.
- Sow the seeds onto the surface of a sandy seed-raising mix.
- Lightly cover with a fine layer of sand or grit and water gently.
- Place in a protected outdoor area; germination usually occurs in spring as temperatures rise.
- Prick out seedlings once they are large enough to handle and grow them on in individual pots.
By Division
Division is the quickest and easiest method for expanding existing mats. Simply use a sharp spade or knife to cut a section of an established plant, ensuring each piece has roots attached. Replant immediately in a prepared site and water well. This can be done almost any time of year, though spring and autumn are ideal for optimal establishment and to minimize stress.
Pests & Diseases
Small-leaved Bidibidi is a remarkably robust plant, rarely affected by serious pests or diseases. It is quite resistant to grazing from deer and rabbits. In very humid or poorly drained conditions, it may occasionally suffer from minor fungal leaf spots, but these rarely impact the overall health of the plant. Ensuring good air circulation and avoiding excessive watering will help keep the plant in prime condition, allowing its bronze foliage to shine.
Cultural Significance
The name 'Bidibidi' or 'Piripiri' is widely applied to various Acaena species and refers to the "clinging" nature of their hooked fruits. For Māori, these plants are a familiar part of the landscape, especially in open, disturbed areas. While not a primary food source, the plants are recognized for their toughness and their ability to thrive in diverse environments. The burrs are a nostalgic part of the New Zealand childhood experience, readily clinging to clothing and socks during walks through the natural bush or grasslands.
- Iconic groundcover
- Part of childhood memories
Bonus Tip
If you are growing Small-leaved Bidibidi where foot traffic or pets are present, be aware that the hooked burrs will attach to clothing and fur. To mitigate this, consider mowing the plant before the burrs fully ripen in summer. This will also encourage denser, more vibrant foliage.
Related Plants
Explore other native plants that share similar characteristics or habitats with Small-leaved Bidibidi ( Acaena microphylla ), offering further insights into New Zealand's diverse flora. These related species provide context and opportunities for complementary planting in your garden.
Plant Conservation
Conservation Status and Threats
Acaena microphylla is currently classified as Not Threatened in New Zealand. It is a widespread and common species, often abundant in suitable habitats. However, local populations can be threatened by intensive development, overgrazing, or competition from aggressive introduced weeds. Protecting its natural habitats, particularly grasslands and open disturbed areas, and promoting its use in appropriate restoration projects are key to ensuring its ongoing success.