Waterwort

Elatine hydropiper

Also known as Eight-stamen waterwort

FreshwaterCarpetingRunnersCuttings

Waterwort (Elatine hydropiper) — Stefan.lefnaer · CC BY-SA 4.0

Care at a glance

Light: High light
CO2: CO₂ required
Temperature: 59–79°F; 15–26°C
Max height: 2 in; 5 cm

Growth rate: Medium
Placement: Foreground
Type: Carpeting
pH: 6.0–7.0
Hardness: 4–8 dGH
Spread: 3.9 in (10 cm)
Nutrient uptake: Root + water column
Growth region: Submersed or emersed
Difficulty: Difficult
Family: Elatinaceae
Origin: Europe, Siberia and northern China

Overview

A demanding nano carpet plant for experienced aquascapers, best in high light with regular CO2, which keeps growth going and prevents melting. It forms a tight small-leaved mat and is planted in little clumps spaced roughly 1.5 cm apart to knit together; expect to trim every few weeks. It dislikes warm, fluctuating temperatures more than most tropical carpets and stays healthier in cooler stable water. Growth is slower than Glossostigma, which actually makes it easier to keep neat once it establishes.

In the wild

A small annual waterwort with a wide Holarctic range, found across Europe up into northern Scandinavia and eastward through Siberia and northern China. It grows in shallow still or slow water, on muddy pond and lake margins and in seasonal pools, tolerating cool conditions and even outdoor cultivation in central European ponds. The aquarium strain in the hobby was originally collected in Italy.

Good to know

Elatine hydropiper belongs to the small family Elatinaceae, the waterworts. The name eight-stamen waterwort refers to its flowers, which carry eight stamens, a feature used to tell it from related Elatine species. Submersed it looks like a miniature Glossostigma elatinoides, but the two are unrelated, and unlike Glossostigma it grows only moderately fast rather than invasively.

Did you know

Despite thriving in heated aquascapes, it is really a cold-tolerant northern plant that will overwinter in outdoor ponds as far north as Scandinavia, so it doubles as a genuine cold-water carpet option.