Pearlweed

Care at a glance

Overview

One of the easiest stem plants going: undemanding, fast, and happy in low-tech tanks without CO2, though injection makes it denser and more compact. Left tall it works as a bright green midground bush; trimmed hard and kept in high light it creeps sideways and can be used as a loose carpet. Prune weekly in a fast tank, and replant tops or let it spread on its own.

In the wild

A small-leaved amphibious plant native to Florida and the southeastern United States, where it grows on wet sandy mud and along the margins of lakes and slow streams. It creeps over damp ground emersed and grows as a loose submersed stem when flooded. In botanical circles it is known as the manatee mudflower and is regarded as endemic to Florida.

Good to know

The accepted botanical name is Micranthemum glomeratum, with Hemianthus glomeratus a widely used synonym in the aquarium trade. Much of the plant sold as pearlweed traces back to the closely related and now possibly extinct-in-the-wild Hemianthus micranthemoides, and the two names are used almost interchangeably by hobbyists. It is placed in Linderniaceae, though some sources still list it under Plantaginaceae.

Did you know

Kept low under strong light it hugs the substrate like a carpet, but let the same plant grow tall and it turns into a bushy background stem, so a single species can fill three different roles in one aquascape depending only on how often you trim it.

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