First Year Planting
Common Name: acaena
Type: Herbaceous perennial
Family: Rosaceae
Zone: 5 to 9
Height: 1.00 to 2.00 feet
Spread: 1.50 to 3.00 feet
Bloom Time: June to August
Bloom Description: White
Sun: Full sun
Water: Dry
Maintenance: Low
Suggested Use: Ground Cover
Flower: Insignificant
Leaf: Colorful
Fruit: Showy
Tolerate: Deer, Drought, Dry Soil, Shallow-Rocky Soil
Culture
Best grown in evenly moist, sandy, well-draining soils in full sun. Tolerates some shade in climates with hot summers. Tolerant of poor, shallow, and rocky soils as long as they are well-draining. Hardy in Zones 6-10. Semi-evergreen in the warmer end of its hardiness range, but will die back to the ground in climates with persistent cold. Easily propagated by division. Will spread rather quickly in ideal climates and can become aggressive. This and other species of Acaena are considered invasive in some areas outside their native range. Consult with local resources before planting.
Noteworthy Characteristics
Acaena inermis, commonly called New Zealand burr or sheep's burr, is a low-growing herbaceous to semi-evergreen perennial native to open, grassy, montane and subalpine areas of New Zealand. This mat-forming ground cover will reach up to 2" tall and spread to fill a 2' area. The compound leaves reach around 1" long and are almost fern-like in appearance, made up of small, toothed leaflets. The foliage can range in color from green to bronzy-purple. In summer, globular clusters of small, white flowers are held above the foliage and mature into showy, red, burr-like seed heads. The seeds are not armed with barbs at the end and will not stick to clothing or animals as readily as other species.
The genus name Acaena comes from Greek and means "thorn", in reference to the barbed seeds of many Acaena species.
The specific epithet inermis means "spineless" or "having fewer spines", in reference to the spininess of the seeds of this species compared to other closely related of Acaena.
The common name refers to the native range of this species.
'Purpurea' is a purple-leaved selection of Acaena inermis. Besides the leaf color, it has similar characteristics to the species.
Problems
No major pest or disease problems of note.
Uses
Suitable for use in rock gardens, alpine gardens, cascading down rock walls, and a ground cover for the front of a mixed border. Tolerates some foot traffic, so can be planted in between stepping stones. This and other species of Acaena are considered invasive in some areas outside their native range. Consult with local resources before planting.