Juncus usitatus
Australian rush
Overview
Juncus usitatus is an evergreen, clumping rush in the family Juncaceae, forming dense tussocks 2-4 feet (0.6-1.2 m) tall of slender, upright, cylindrical green stems. The stems are smooth and round in cross-section, 0.04-0.1 inch (1-3 mm) wide, filled with continuous white pith, with leaves reduced to brown sheaths at the base. Branched clusters of small brown flowers form near the stem tips from spring through summer, followed by tiny three-celled capsules holding numerous minute seeds. Clumps enlarge steadily by short rhizomes and self-seed freely where soil stays moist. The species grows along creek banks, drains, dam margins, and damp ground, tolerating periods of flooding as well as short dry spells once established. Growth is rapid in warm, moist conditions. In drier sites the tussock thins and the stem tips brown off. The plant holds its green colour year-round in mild climates.
Native Range
Native to eastern Australia, from Queensland through New South Wales to Victoria, and in parts of South-East Asia. Grows along watercourses, drainage lines, swamp margins, and damp pasture, on clay, loam, and sandy soils that hold moisture.Suggested Uses
Planted along pond and dam margins, in rain gardens, swales, and erosion-control plantings at 18-24 inch (45-60 cm) spacing. Used in constructed wetlands and bank stabilisation for its dense fibrous roots and tolerance of wet soil. The self-seeding habit suits naturalistic plantings but can spread into damp lawns and beds.How to Identify
Appearance
Size & Dimensions
Height2' - 4'
Width/Spread1'6" - 3'
Reaches mature size in approximately 2 years
Bloom Information
Flowers from spring through summer (September to February in its native range), producing branched clusters of small brown flowers near the stem tips. The flowers are wind-pollinated and inconspicuous. Seed follows over the warmer months and self-sows readily on bare, moist soil.
Detailed Descriptions
Foliage Description
GreenGrowing Conditions
Sun Requirements
Requires 5-12 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
Grow in moist to wet soil in full sun to part shade, as the species tolerates flooding and damp ground far better than dry sites. Plants accept clay, loam, and sandy soils and need little feeding. Clumps spread by rhizome and seed and can be divided in spring to manage size. Cut tussocks back near ground level in late winter to remove old stems and refresh growth. No serious pests or diseases affect the species. Self-sown seedlings appear around established clumps on bare moist soil.Pruning
Cut clumps back to about 4 inches (10 cm) in late winter to clear old and browned stems before new growth. Division in spring controls clump size and renews vigour. No other pruning is required.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
winter
Container Growing
✓ Suitable for container growing
Minimum container size: 5 gallons