New Zealand Burrs SEEDS, Ground covers

Acaena microphylla — New Zealand Burrs — is a fast-spreading, low-growing alpine ground cover forming a bronzy mat of intricate, lacy foliage just 3 inches tall. Greenish flowers appear in early summer and mature into eye-catching bright red burrs by mid-summer — an ornamental feature in its own right and unique among ground covers. Evergreen in mild winter climates; recovers quickly from hard winters with fresh foliage. An excellent, vigorous choice for between flagstones, rock gardens, edging, and as a lawn substitute in areas with light foot traffic. USDA Zones 5–8.

Note: Acaena spreads vigorously — plant thoughtfully and monitor spread in smaller gardens.

Plant Highlights

• Bronzy, lacy foliage mat just 3 inches tall; spreads 12–24 inches wide — dense and vigorous
• Bright red ornamental burrs in summer — striking, unusual feature
• Evergreen in mild winters; rebounds quickly after hard winters
• Fast-spreading; excellent for flagstone gaps, rock gardens, dry banks, and edging
• Light foot traffic tolerance
• USDA Zones 5–8

Sowing Guide

Acaena requires a two-stage temperature treatment for best germination:

1. Warm humid phase: Keep seed at warm, humid conditions for 2–3 weeks.
2. Cold phase: Move to 35–39°F for 4–6 weeks (cold stratification).
3. Germination phase: Germination occurs at 41–55°F after cold treatment. Germination time is highly variable: 30–120 days.

Alternative: If two-stage stratification is not possible, sow when frost season is nearly over and outdoor temperatures naturally range 41–55°F for best results.

Depth: Surface sow — do not cover. Light required for germination.

Rate: 3–5 seeds per plant; approximately 100 seeds covers 20 square feet.

Care Guide

Light: Full sun to partial shade.

Soil: Well-drained; pH 5.8–6.8. Tolerates poor, rocky soils.

Division: Divide easily in early fall or spring to control spread and increase stock.

Winter: Clip back any winter-damaged foliage — plants regrow quickly with fresh foliage.

Planting Specs

• Common name: New Zealand Burrs, Biddy-biddy
• Botanical name: Acaena microphylla
• Type: Perennial alpine ground cover; evergreen in mild climates
• Bloom: Greenish flowers maturing to bright red burrs
• Bloom/burr season: Early to late summer
• Height: 3 inches | Width: 12–24 inches
• Growth rate: Fast
• USDA Zones: 5–8
• Light: Full sun to partial shade
• Soil: Well-drained; pH 5.8–6.8
• Foot traffic: Light
• Sowing: Surface sow | Germ: 30–120 days at 41–55°F (two-stage stratification recommended)
• Coverage: ~100 seeds per 20 sq ft