Green cabomba

Cabomba caroliniana

Also known as Carolina fanwort, Fanwort, Cabomba, Washington grass

FreshwaterStemCuttingsSide shoots

Invasive. Invasive and regulated in parts of the US (banned for sale in some states) and elsewhere. Never release into the wild; dispose of in the trash.

Green cabomba (Cabomba caroliniana) — Leslie J. Mehrhoff, University of Connecticut, Bugwood.org · CC BY 3.0

Care at a glance

Light: High light
CO2: CO₂ beneficial
Temperature: 64–82°F; 18–28°C
Max height: 23.6 in; 60 cm

Growth rate: Fast
Placement: Background
Type: Stem
pH: 6.0–7.5
Hardness: 2–15 dGH
Spread: 3.1 in (8 cm)
Nutrient uptake: Root + water column
Growth region: Submersed
Difficulty: Medium
Family: Cabombaceae
Origin: Southeastern North America and subtropical South America (Brazil, Argentina)

Overview

Green cabomba is a fast, feathery stem plant for the background, rated medium in difficulty. It is a regulated noxious weed in many places, so check local rules before keeping it.

Did you know

Green cabomba's weediness gave it the nickname Washington grass, even though Washington State bans its sale.

Caring for green cabomba

Plant green cabomba in thick groups at the back of the tank. The brittle stems uproot easily, so weight or anchor them until they root. It dislikes being shaded or disturbed and does best in a stable, high-flow tank.

It needs strong light to stay dense. Injected CO2 is not required, but added CO2 and good iron dosing keep it full and growing faster. It feeds through both roots and leaves, so pair root tabs with a liquid fertilizer. Keep it at 64 to 82°F (18 to 28°C) with a pH of 6 to 7.5.

It grows fast, to about 24 in (60 cm), so expect to trim it often. Replant the cut tops, and the stumps send out side shoots you can plant once they have a few leaves. Under weak light it goes leggy and the lower stems strip bare.

Never release trimmings or old plants into natural water. A single broken stem fragment can root and start a whole new infestation.

Good to know

Green cabomba belongs to Cabombaceae, a small family of aquatic plants closely tied to the water lilies. Its submersed leaves grow in opposite pairs, each split into a fan of fine segments. At flowering it makes small, shield-shaped floating leaves. Cabomba caroliniana is listed as a noxious or prohibited aquatic weed in numerous US states. States that restrict it include CA, CT, ME, MA, MI, NH, NY, VT and WI. It is also invasive across parts of Europe, Asia, Australia and Canada.

In the wild

Green cabomba is native to the southeastern United States, in Florida, the Gulf states and the Carolinas, and to subtropical Brazil and Argentina. It grows rooted in slow streams, ponds and ditches with its fine fan leaves fully submersed. It spreads readily from stem fragments, which is how it has escaped into waterways well outside its native range. It is essentially an underwater plant and does poorly grown emersed.

Common questions

Does green cabomba need to be planted in the substrate?

Yes. Strip the leaves from the lower part of each stem, then push the stems into the substrate one at a time, a little apart.

Does green cabomba need CO2?

No, but it helps. Green cabomba can grow without injected CO2, and added CO2 makes it grow faster.

How much light does green cabomba need?

Green cabomba needs high light from a strong planted-tank LED. In weaker light its stems stretch and drop their lower leaves.

Does green cabomba need root tabs?

They help. Green cabomba takes nutrients through both its roots and its leaves. Root tabs near its roots and a liquid fertilizer cover both.

How do you propagate green cabomba?

Green cabomba propagates by cuttings and side shoots. Cut off the top of a stem and replant it, and the stump left behind grows new shoots. Cut a side shoot off once it has a few leaves and plant it on its own.