Plants
Dwarf Hygro
Hygrophila polysperma
Origin: Dwarf hygro comes from South and Southeast Asia — India, Bhutan, and Bangladesh. It grows in marshy shallows, ditches, and rice fields, readily moving from water onto land.
Also known as: Indian swampweed, Miramar weed, Hygrophila polysperma
Fact sheet
- Height
- 40 cm
- Temperature
- 18–30 °C
- pH
- 6–8
- Lighting
- Low
- CO₂
- Not needed
- Growth rate
- Fast
- Placement
- Midground, Background
Overview
Dwarf hygro is one of the most undemanding and fast-growing aquarium plants, a classic for beginners. It grows under almost any light without CO2 and forgives any mistake, earning it the label 'weed' in the good sense. Upright stems with small leaves quickly form a background and actively consume excess nutrients, helping against algae. Because of its hardiness and spread it is banned as invasive in some countries (such as the USA).
Appearance
Thin upright stems bear opposite oblong-lanceolate leaves 2–5 cm long, light green. Under bright light the tips turn pink and the internodes shorten. Height is up to 40 cm. The plant branches and thickens fast.
Care
Extremely undemanding: very low to strong light, 18–30 °C, pH 6.0–8.0, any reasonable hardness range. CO2 is not required. It grows very fast and needs frequent trimming.
Fertilizing
It feeds through roots and leaves; its needs are minimal. It quickly takes up excess nitrate and phosphate, cleaning the water. It responds to macronutrients with faster growth.
Breeding
It propagates by cuttings: any stem fragment roots. Side shoots branch abundantly from the main stem.
Fun facts
Because of its hardiness and aggressive spread, dwarf hygro is banned from import in several US states as an invasive species. It is one of the most 'unkillable' aquarium plants. A popular variegated form, 'Rosanervig', has pink-white veins.