Onion plant natans

Crinum natans

Also known as African onion plant, Floating crinum, Water onion, Crinum aquatica

FreshwaterBulb / tuberBulb offsets

Onion plant natans (Crinum natans) — Zaire at de.wikipedia · CC BY-SA 3.0

Care at a glance

Light: Medium light
CO2: No CO₂ needed
Growth rate: Slow
Placement: Background
Type: Bulb / tuber
Temperature: 72–82°F (22–28°C)
pH: 5.5–8.0
Hardness: 4–18 dGH
Max height: 39.4 in (100 cm)
Spread: 11.8 in (30 cm)
Nutrient uptake: Root + water column
Growth region: Submersed
Difficulty: Easy
Origin: Tropical West and Central Africa
Family: Amaryllidaceae

Overview

A tough, undemanding, low-tech bulb plant that suits the background of larger tanks. Plant it so the top half of the bulb stays above the substrate and exposed to the water, since burying the whole bulb causes rot. It grows slowly, often just a few new leaves a month, so it resents being moved once established. Good flow and a nutrient-rich root zone keep the long leaves healthy; CO2 is not needed.

In the wild

Widespread across tropical West and Central Africa, growing fully submersed in rivers and streams and reaching into the brackish tidal zone near the coast. It grows from an onion-like bulb and sends up long, wavy, strap-shaped leaves that trail with the current. In the wild the leathery leaves can run to well over a metre long.

Good to know

Crinum natans is a bulbous member of the Amaryllidaceae, the amaryllis family, making it a relative of true onions and lilies rather than typical aquarium sword plants. Its dark green leaves are strap-shaped and strongly undulate, up to about 1.4 m long and 2 to 5 cm wide. Mature, thriving plants can send a flower stem to the surface bearing a fragrant white lily-like bloom.

Did you know

Did you know it is a cousin of the garden onion? It grows from a real bulb in the amaryllis family, and a happy specimen will occasionally push a stalk to the surface and open a scented white flower like a pond lily.