Grasses
Acorus calamus
Sweet flag
Upright, sword-shaped green leaves give pond edges and wet beds a clean vertical accent. Leaves and rhizomes are aromatic when crushed, while spreading roots gradually build a colony. Unlike drought-loving grasses, sweet flag needs consistent moisture and can grow in shallow water; use a container to limit its spread.
At a glance
- Sun
- Full sun to part shade
- Mature size
- Height: 2–2½ ft. · Spread: 1½–2 ft.; spreads over time
- Water
- Consistently moist to wet
- Hardiness
- USDA 4–10
Sizes & prices
- 6"$14.99
Catalog updated September 8, 2026. This is not a live stock count; please call to confirm availability and price.
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Resistance & tolerances
- Drought
- Poor tolerance; leaves scorch when dry.
- Wet soil
- Tolerates boggy soil and water up to 9 in. deep.
Seasonal interest
- Habit
- Deciduous, spreading aquatic perennial.
Growing & care
- Soil
- Wet garden soil or shallow pond margins.
- Maintenance
- Divide or contain rhizomes to manage spread.
Sources & photo credits
Photo: Giles Watson's poetry and prose · CC BY-SA 2.0
Reviewed October 1, 2026. Growing conditions vary by location.