Acaena magellanica aka Buzzy Burr
Taxonomy ID: 4803
Acaena magellanica is a vigorous mat-forming perennial groundcover native to the southern regions of South America and numerous subantarctic islands. This evergreen member of the Rosaceae (rose) family is characterized by its creeping stems and attractive blue-grey pinnate foliage, which forms dense carpets reaching only 6-14 cm (2-6 inches) in height but spreading extensively up to 90 cm (36 inches) wide.
The leaves are oblong to linear-lanceolate, composed of 5 to 10 pairs of small, serrated ovate leaflets that create a fine-textured appearance. The foliage measures 4-15 cm in length and provides year-round interest with its distinctive blue-grey coloration.
During summer (typically June through August in the Northern Hemisphere), Acaena magellanica produces tiny flowers in dense globular heads borne on wiry stems that rise above the foliage. The flowers are petal-less, appearing in shades of brown, white, or with purple-red tinges. Following pollination, the flower heads develop into the plant's most distinctive feature: decorative red-brown seed balls covered in barbed, arrow-headed burrs. These burrs are adapted for animal dispersal, readily attaching to fur and feathers.
In its native habitat, this species thrives in challenging subantarctic conditions, growing from sea level to alpine zones beyond 2,000 meters elevation. It tolerates extended periods of snow cover and temperatures as low as -20°C. The plant is found in diverse habitats including coastal areas, bogs, riverbanks, and mountain slopes, often forming extensive ground-covering patches.
Acaena magellanica is valued in horticulture as a robust groundcover for rock gardens, between paving stones, and for erosion control. Its tolerance of foot traffic, drought resistance once established, and evergreen nature make it a practical choice for difficult garden situations. However, gardeners should note its vigorous spreading habit may require management to prevent it from overtaking other plants.
Common names
Buzzy Burr, Greater Burnet, New Zealand Burr, Cadillo, Prickly BurnetMore information about Buzzy Burr
How difficult is it to grow Acaena magellanica?
Acaena magellanica is an easy-to-grow groundcover that thrives with minimal care. Once established, it is drought-tolerant, deer-resistant, and can even tolerate light foot traffic. The main challenge is controlling its vigorous spreading habit, which may require occasional removal of rooted stems from areas where you don't want it to grow.
How big does Acaena magellanica grow?
Acaena magellanica is a low-growing mat-forming groundcover reaching only 5-14 cm (2-6 inches) in height, though flower stems may rise slightly higher. It spreads horizontally to 30-90 cm (12-36 inches) wide through creeping stems that root as they grow. It is a fast-growing plant that can form dense carpets relatively quickly.
Where is Acaena magellanica native to?
Acaena magellanica is native to the southern tip of South America (Chile and Argentina) and numerous subantarctic islands. Its range includes the Falkland Islands, South Georgia, Heard Island, Kerguelen Islands, Crozet Islands, Prince Edward Islands, and Macquarie Island. It grows from coastal areas up to alpine zones exceeding 2,000 meters elevation.
What soil does Acaena magellanica need?
Acaena magellanica requires well-draining, sandy or gritty soil. It cannot tolerate waterlogged conditions and will die if left in standing water. The plant actually prefers poor-quality soil and does not need rich or fertile conditions. Good drainage is the most critical factor for success.
What temperatures can Acaena magellanica tolerate?
Acaena magellanica is extremely cold-hardy, tolerating temperatures as low as -15°C to -20°C (5°F to -4°F) and extended periods of snow cover. It is rated UK hardiness H5 and thrives in USDA zones 5-10. Its native subantarctic habitat means it is well-adapted to cool, temperate climates but can also grow in warmer regions.
How do you propagate Acaena magellanica?
Acaena magellanica can be propagated by division or from seed. For division, gently separate clumps in spring or autumn when the soil is fairly dry. For seeds, sow in an open frame or cold greenhouse from autumn through spring. Seeds benefit from cold stratification and typically germinate within 1-4 weeks at temperatures of 10-15°C (50-59°F).
Does Acaena magellanica need pruning?
Acaena magellanica requires minimal pruning. Cut back lightly in spring to maintain shape and encourage fresh growth. More importantly, regularly remove rooted stems from areas where you don't want the plant to spread, as it can be quite vigorous. Removing old seed heads after flowering can also encourage new growth.
Can Acaena magellanica be grown outdoors?
Acaena magellanica is exclusively an outdoor plant, ideal for rock gardens, between paving stones, and as groundcover. It tolerates light foot traffic, making it excellent for paths and patios. Hardy to USDA zones 5-10 and UK hardiness H5, it can be grown outdoors year-round in most temperate climates.
When and how does Acaena magellanica flower?
Acaena magellanica flowers during summer, typically June through August in the Northern Hemisphere. The tiny, petal-less flowers are brown, white, or purple-tinged and form dense globular heads on wiry stems above the foliage. After flowering, distinctive red-brown burr-like seed heads develop, covered in barbed spines that attach to animals for seed dispersal.
What pests and diseases affect Acaena magellanica?
Acaena magellanica is generally pest and disease-free. It is deer-resistant and its tough nature means it rarely suffers from significant problems. The main concern is overwatering or poor drainage, which can lead to root rot. Ensure well-draining soil and avoid watering from above to prevent standing water on foliage.
