Ornatec InternationalSpecies reference sheet ยท ornatecinternational.com
Acorus gramineus
Japanese Sweet Flag
Acorus gramineus, the Japanese Sweet Flag, is a low, evergreen, grass-like perennial that spreads slowly by a creeping rhizome to form a dense mat of narrow, fan-arranged leaves. The foliage carries a sweet spicy scent when bruised, and the plant holds its colour through the year wherever the ground stays damp. It is not a true grass, but it is used exactly as one in planting schemes.
Specifiers reach for it at the wet edge of a scheme, where turf fails and a marginal aquatic is too coarse: pond and stream margins, rain gardens, swale bases and the shaded damp ground under trees.
Specifications
- Height0.2 to 0.4 metres
- Width0.3 to 0.5 metres, spreading slowly by rhizome
- Native toEast Asia, including Japan, Korea and China
- FoliageNarrow, arching, strap-shaped leaves held in flattened fans, mid-green and aromatic when crushed; evergreen
- Growth rateSlow to moderate
Conditions
- SoilPrefers consistently moist to wet, humus-rich soils; tolerates shallow standing water and heavy ground
- LightFull sun to partial shade
- WaterHigh; needs permanently moist soil and is not drought-tolerant
- ClimateThrives in temperate and subtropical regions; frost hardy
Additional Features
- FormDense, low, fan-leaved clump that knits into a continuous mat
- UsesIdeal for pond and stream margins, rain gardens, swale planting, damp shaded ground cover and soft edging to water features
- SpacingPlant 0.2 to 0.3 metres apart for a closed mat within two seasons
- Low MaintenanceCut back tired foliage in late winter; divide congested clumps every few years
- Pest ResistanceGenerally trouble free
- VersatilityWorks as a marginal aquatic in shallow water or as a ground cover in permanently moist borders
Japanese Sweet Flag is the reliable answer to the damp, part-shaded ground that defeats most ground covers.
Availability by project review. Sizes, quantities, origin and export readiness are confirmed after your plant schedule is reviewed against destination, timing and quarantine requirements. MEWA certified for supply into Saudi Arabia; Australian Export Registered Establishment.
Enquiries: sales@ornatecinternational.com
310 Donkin Rd, Utchee Creek QLD 4871, Australia
Prepared 09 September 2026