Dwarf sagittaria

Sagittaria subulata

Also known as Dwarf sag, Awl-leaf arrowhead, Narrow-leaved arrowhead, Sagittaria subulata var. subulata

FreshwaterRosetteRunners

Dwarf sagittaria (Sagittaria subulata) — Krzysztof Ziarnek, Kenraiz · CC BY-SA 4.0

Care at a glance

Light: Low light
CO2: CO₂ beneficial
Growth rate: Medium
Placement: Foreground
Type: Rosette
Temperature: 64–82°F (18–28°C)
pH: 6.0–8.0
Hardness: 2–18 dGH
Max height: 11.8 in (30 cm)
Spread: 3.1 in (8 cm)
Nutrient uptake: Root + water column
Growth region: Submersed or emersed
Difficulty: Beginner
Origin: Eastern USA and South America
Family: Alismataceae

Overview

Use it as a foreground or low midground carpet, planting individual rosettes a few centimeters apart so the runners can knit them together. It is genuinely beginner-friendly and grows in low light without CO2, though added CO2 and brighter light make it shorter, denser and faster to fill in. It is a heavy root feeder that yellows quickly with iron deficiency, so push root tabs or a nutrient substrate. The main pitfall is height: under strong light in a deep tank it can shoot up tall and stringy, so trim runners and thin it to keep a low lawn.

In the wild

Sagittaria subulata grows wild along the eastern seaboard of the United States and into South America, in fresh and brackish marshes, ponds, slow rivers and tidal creeks. It is a grass-like rosette plant that roots in soft mud and spreads sideways by runners, often forming dense submerged lawns. Its tolerance of brackish water and a very wide temperature range reflects how variable its native habitats are.

Good to know

It belongs to the arrowhead family Alismataceae and is a true Sagittaria, related to the larger arrowhead plants, despite its slim grass-like submerged form. Emersed plants can throw up arrowhead-shaped aerial leaves and small white three-petaled flowers, which is how the genus gets its common name. Leaf width and final height vary a lot between populations and growing conditions, so trade material ranges from short narrow forms to broad-leaved plants over 30 cm tall.

Did you know

Did you know dwarf sag tolerates brackish water? In parts of its native US range it grows in tidal zones with measurable salinity, which is unusual for a popular freshwater carpeting plant.