Gonocarpus micranthus
creeping raspwort
Eastern and southern Australia, New Zealand, eastern Asia
Overview
Gonocarpus micranthus is a low, mat-forming perennial herb in the family Haloragaceae, growing 2-4 inches (5-10 cm) tall and spreading 8-16 inches (20-40 cm) across. Slender four-angled stems, often flushed red, creep along the ground and root at the nodes, building loose mats over damp soil. The opposite leaves are ovate to elliptic, 0.1-0.4 inch (3-10 mm) long, with shallowly toothed margins; foliage is green in shade and turns bronze-red in full sun or cold weather. From late spring into summer the plant produces slender terminal spikes of minute flowers under 0.08 inch (2 mm) wide, each with four small reddish to greenish sepals, followed by tiny ribbed nut-like fruits about 0.04 inch (1 mm) long. The species occupies a wide range of damp habitats and tolerates seasonal waterlogging, but it declines in prolonged drought and in deep shade, where stems grow lank and sparse. It spreads steadily where moisture is reliable and can knit into surrounding low vegetation. Growth is densest in cool, moist conditions and slows markedly through hot, dry summers.
Native Range
Gonocarpus micranthus is native to eastern and southern Australia, including Queensland, New South Wales, Victoria, Tasmania, and South Australia, and also occurs in New Zealand and parts of eastern Asia. It grows in damp grassland, heath, swamp margins, and montane to subalpine sites.Suggested Uses
Used as a groundcover in moist rockeries, pond and bog margins, and damp native garden beds. It knits between stepping stones and stabilises soil in consistently moist, low-traffic areas.How to Identify
Appearance
Size & Dimensions
Height2" - 4"
Width/Spread8" - 1'4"
Bloom Information
Detailed Descriptions
Foliage Description
Green to bronze-redGrowing Conditions
Sun Requirements
Requires 4-8 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 Gonocarpus micranthus in full sun to part shade in soil that stays consistently moist to seasonally wet. It adapts to a range of textures from sandy loam to clay, so long as drainage is not sharply dry. Water regularly during establishment and through dry spells, as the species declines without reliable moisture. It withstands light to moderate frost once established. Growth is fastest in cool, humid conditions; hot dry summers slow it and can scorch exposed mats. A light application of compost in spring supports denser cover.Pruning
Light trimming or mowing in late winter to early spring removes worn growth and encourages fresh mats. Stems that root as they creep can be cut back to keep the plant within a bed. No structural pruning is required.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
winterearly spring
Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons