Swamp stonecrop (Crassula helmsii) care guide

Group
Plants
Other names
New Zealand pigmyweed, Swamp stonecrop, Australian swamp stonecrop, Tillaea recurva, Crassula recurva
Family
Crassulaceae (stonecrop family)
Origin
Australia and New Zealand; introduced to the British Isles, mainland Europe, Russia and the USA
Water
freshwater
Temperature
5–22°C
pH
6–8
Care level
beginner
Lighting
Medium light; CO2 not needed

Care

Legal note: this plant may not be sold on Aquatic-Auctions to buyers in England and Wales, where its sale has been banned since 2014 because it is invasive (check GOV.UK for the current rules). It is also an offence to plant it or cause it to grow in the wild. New Zealand pigmyweed (swamp stonecrop) is a small succulent water plant from Australia and New Zealand. It has stiff shoots with narrow leaves in opposite pairs, 4–24 mm long, and stays green all winter. Small white four-petalled flowers appear above water in summer. It grows on muddy pond margins and also semi- or fully submerged in deeper water, and it can be kept submerged in a cool aquarium. Once established it grows vigorously, forming dense mats that smother native plants, which is why it is a serious invasive weed. Water figures are our estimate, not from the sources. Never release this plant or dispose of it in drains or waterways; it is invasive in some countries. Sources: Wikipedia (en.wikipedia.org/wiki/Crassulahelmsii); Wikipedia, List of freshwater aquarium plant species. Checked October 2026.

Breeding

Regrows from the tiniest fragments, which is what makes it so invasive. Dispose of trimmings by drying them out or composting them well away from water.

Compatibility and tank mates

A coldwater plant; fish generally leave it alone. Do not keep it in outdoor ponds where it can escape.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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