perennial
Japanese sweet flag 'Ogon'
Acorus gramineus 'Ogon'
Preview: plant data is awaiting horticulturist review. A professional horticulturist hasn't reviewed our plant table yet. Lists still follow fixed rules for zone, sun, pets, deer and invasive status.
Japanese sweet flag 'Ogon' is a semi-evergreen perennial hardy in zones 6–9. Expect 0.75–1 ft of height and 0.75–1.25 ft of spread; our lists space it 1 ft apart. It does best in part sun to part shade with steady moisture, and it copes with wet soil. It is grown for its foliage rather than its flowers. In a FloraVista list it usually plays the grass role: a grass-like plant with narrow leaves that adds fine texture in the middle of the bed. Deer usually leave it alone, and it is toxic to dogs and cats. Our rules leave it out of lists in the Desert Southwest, where summer heat, humidity or mild winters hold it back even inside its zone range.
Facts from our plant table
- Botanical name
- Acorus gramineus 'Ogon'
- Plant type
- Perennial, semi evergreen
- Hardiness zones
- 6 to 9
- Sun
- Part sun (4–6 hours); Part shade (2–4 hours)
- Water
- High; tolerates wet soil
- Soil
- Moist to wet soil; fine at pond and rain-garden edges.
- Mature size
- 0.75–1 ft tall × 0.75–1.25 ft wide
- Spacing
- 1 ft apart (centre to centre)
- Growth rate
- Medium
- Bloom
- Grown for foliage
- Roles in a bed
- Grass, Edge
- Styles
- modern, classic
- Deer resistance
- High: deer rarely eat it
- Pets
- Toxic to dogs and cats. Acorus contains asarone; A. calamus is considered toxic. Not confirmed for this species, so marked toxic.
- Native to
- Not native to the US (or a garden hybrid)
- Pot size and price
- 1-gallon pot, typically $10–$16 (sometimes stocked)
- Plant in
- Spring or Fall
- First-year watering
- Keep the soil consistently moist the whole first year; water two or three times a week in summer heat. Mulch to hold moisture.
- Pruning
- Trim brown leaf tips in spring.
Sources: Missouri Botanical Garden Plant Finder; state extension service fact sheets; ASPCA toxic and non-toxic plant list; Rutgers NJAES deer resistance ratings; state extension service; Invasive Plant Atlas of the United States; state noxious weed and invasive plant lists; US garden-centre and home-improvement retail listings (general knowledge, 2026 estimate). Not yet reviewed by a horticulturist.
Good companions
The plants our list engine most often puts in the same bed as Japanese sweet flag 'Ogon', across the sun, zone, pet, deer and style combinations it fits.
- Japanese sedge 'Evergold'Carex oshimensis 'Evergold'ornamental grass · zones 5–9
- Hairy alumroot 'Caramel'Heuchera villosa 'Caramel'perennial · zones 4–9
- Daylily 'Stella de Oro'Hemerocallis 'Stella de Oro'perennial · zones 3–9
- Bigleaf hydrangea 'Endless Summer'Hydrangea macrophylla 'Bailmer'shrub · zones 5–9
- Dwarf panicle hydrangea 'Little Lime'Hydrangea paniculata 'Jane'shrub · zones 3–8
- Catawba rhododendron 'Roseum Elegans'Rhododendron catawbiense 'Roseum Elegans'shrub · zones 4–8
If you can't find it
Substitutes our engine offers for Japanese sweet flag 'Ogon': same role in the bed, passing the same rules.
How this page was made
This page was generated from this plant's record in FloraVista's plant table by fixed rules. The companions and substitutes come from the lists our rules engine composes. No named expert has reviewed this page.
Data status: the plant table is awaiting review by a horticulturist. Check each plant with a local nursery or extension office before you buy.
Sources
- Missouri Botanical Garden Plant Finder, state extension services and the USDA PLANTS database (zones, size, sun, water, bloom, native range)
- ASPCA toxic and non-toxic plant lists (dog and cat toxicity)
- Rutgers NJAES and regional extension deer-resistance ratings
- State noxious-weed and invasive-plant lists and the Invasive Plant Atlas of the US
- Typical US garden-centre listings (pot size and price band)
Generated . How FloraVista chooses plants