Lake cress

Rorippa aquatica

Also known as Water horseradish, Water cabbage, Armoracia aquatica, Neobeckia aquatica

FreshwaterStemadventitious_plantletsCuttings

Lake cress (Rorippa aquatica) — Aquarium Plants Factory · Used with permission

Care at a glance

Light: Medium light
CO2: No CO₂ needed
Temperature: 64–79°F; 18–26°C
Max height: 11.8 in; 30 cm

Growth rate: Slow
Placement: Midground
Type: Stem
pH: 6.0–7.5
Hardness: 2–15 dGH
Spread: 4.7 in (12 cm)
Nutrient uptake: Root + water column
Growth region: Submersed or emersed
Difficulty: Medium
Family: Brassicaceae
Origin: Native to slow streams, ponds, and swamps of central and eastern North America.

Overview

Lake cress grows slowly even under good conditions, preferring medium to high light, a rich substrate, and cooler water around 20 to 25 C. It does fine with or without CO2 and works in the foreground to midground. It spreads mainly from plantlets that form on detached leaves floating at the surface, so those can be collected and replanted.

In the wild

Rorippa aquatica changes leaf shape with its conditions, producing deeply cut, almost fern-like submerged leaves and simpler, toothed leaves above water. It grows in slow streams and ponds, floating or rooting in shallow margins. Underwater it forms a low, feathery rosette.

Good to know

Rorippa aquatica is a member of the mustard family, Brassicaceae, and has also been known as Armoracia aquatica and Neobeckia aquatica. It is well known to botanists for heterophylly, changing leaf shape in response to temperature and submersion. Researchers study it to understand how plants control leaf form.

Did you know

It is a favorite of plant scientists because it changes its leaf shape with temperature, growing lacy, dissected leaves underwater and simpler leaves in the air.