---
title: Dwarf sweet flag in a terrarium | Glass Jar Garden
description: Dwarf sweet flag (Acorus gramineus 'Pusillus'): Bright grassy tufts for wet ground and pond edges. Needs light 2,500 to 15,000 lux, humidity 60 to 100 % RH,...
url: https://glassjar.garden/guide/plants/acorus-gramineus-pusillus/
---

Plants

# Dwarf sweet flag
Acorus gramineus 'Pusillus'

Beginner · Fine in a closed jar

Bright grassy tufts for wet ground and pond edges.

## What the simulation uses

- Light: 2,500 to 15,000 lux (The brightness it grows well in.)

- Humidity: 60 to 100 % RH (Air moisture it is happy in; below the lower end it dries out.)

- Temperature: 10 to 28 °C (Comfortable range; outside it growth slows.)

- Dies at: below -15 or above 35 °C (Days beyond these temperatures kill it.)

- Soil pH: 5.5 to 7.5 pH (Soil acidity it prefers.)

- Grows up: 0.4 cm/month (How fast it gains height in good conditions.)

- Spreads: 0.65 cm/month (How fast its edge creeps outwards.)

- Copes with wet: excellent (How well it stands soggy soil; poor means rot comes quickly.)

- Copes with still air: good (Sealed jars have still air; poor means grey mould finds it.)

- Copes with shade: fair (How well it holds on in dim light.)

- Copes with drying: poor (How well it survives the jar drying out.)

- Water use: 0.07 ml/cm²/day (Water drawn up from its roots per cm² of leaves in room air; a sealed jar cuts this to a fraction and returns it down the glass.)

- Leaf drop: 2 %/month (Share of its leaves it sheds each month as litter for the cleanup crew.)

- Soft leaves: no (Soft new growth that hungry isopods will nibble.)

- Full size: 7.5 cm tall, 11.5 cm wide (Its size when grown, before the lid stops it.)

## Care

- Day length: 10 to 14 h

- Substrate: Wet

## What kills it

- drying out

## Description
Happy in waterlogged ground, it grows half in and half out of water. It is a staple of bogs and tanks that mix land and water. Keep the soil wet and it will settle in easily.

Also called dwarf japanese rush, acorus pusillus.

Estimated, where sources were thin: rates and limits are horticultural estimates, not measured.

## Sources

- [en.wikipedia.org/wiki/Acorus_gramineus](https://en.wikipedia.org/wiki/Acorus_gramineus)

[Grow it in a jar](https://glassjar.garden/?guide=plants/acorus-gramineus-pusillus)

[Dwarf mondo grass 'Nana'](https://glassjar.garden/guide/plants/ophiopogon-japonicus-nana/) · [Earth star](https://glassjar.garden/guide/plants/cryptanthus-bivittatus/) · [All plants](https://glassjar.garden/guide/plants/)