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Spinifex spp.
coastal spinifex
Coasts of the Indian and Pacific Oceans
Overview
Spinifex spp. is a genus of coastal, sand-binding perennial grasses in the family Poaceae, native to the shores of the Indian and Pacific Oceans, including Australia, New Zealand, and South-East Asia. Plants spread by long, creeping runners that root at the nodes, sending up tufts of stiff, inrolled, blue-green to grey-green leaves 6-18 inches (15-45 cm) tall and binding loose sand into low dunes. The genus is dioecious, with male and female flowers on separate plants. Female plants form large, spherical, spiky seed heads up to 8 inches (20 cm) across that break free at maturity and roll along the beach on the wind, scattering seed as they go. The grasses grow on open coastal sand in full sun and tolerate salt spray, wind, drought, and burial by shifting sand. They spread widely and are grown mainly for dune stabilization rather than border use. Foliage stays grey-green year-round in frost-free coastal climates.
Native Range
Spinifex spp. is native to the coasts of the Indian and Pacific Oceans, from eastern and southern Africa and South-East Asia to Australia, New Zealand, and the Pacific islands. The grasses grow on foredunes, beaches, and sandy coastal flats subject to salt spray and wind.Suggested Uses
Used mainly for dune stabilization, beach restoration, and erosion control on coastal sand. Spaced 24-36 inches (60-90 cm) apart, the runners knit drifting sand into low dunes. It also features in coastal and water-wise gardens within its native range.How to Identify
Appearance
Size & Dimensions
Height6" - 1'6"
Width/Spread3' - 10'
Bloom Information
Flowering occurs mainly in spring and summer. Male plants bear narrow spikelet clusters, while female plants form the large, radiating, spherical seed heads. The mature female heads detach and roll along the beach, dispersing seed through the warmer months.
Detailed Descriptions
Flower Description
Greenish to strawFoliage Description
Blue-green to grey-greenGrowing Conditions
Sun Requirements
Requires 6-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Plants grow in full sun on deep, freely draining coastal sand and tolerate a wide pH from about 6.0 to 8.5. They withstand salt spray, strong wind, drought, and partial burial, conditions few other grasses survive, and need no feeding. Establishment is from runners or divisions planted into bare sand and watered until rooted, after which they are self-sufficient. They do not tolerate heavy, wet, or shaded soils away from the coast. Spread is by surface runners, which can cover wide areas. Hardiness suits frost-free to light-frost coastal regions, roughly USDA zones 9 to 11.Pruning
No routine pruning is needed. Old or storm-damaged foliage can be cleared to tidy the clumps. Runners that spread beyond the wanted area are cut back at the margins.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
winter