These hardy plants, with their paired oval leaves, can be made to flower in an
aquarium, but taking cuttings is the best way to propagate. They prefer water that
is neutral or slightly acid and not too hard, and are best planted in groups, with
small spaces between their stems.
The hardy water hyssop tolerates temperatures as low as 20°C, but will not stand
those above 24-25°C. Size: 30 cm.
There is more space between the leaves than in the above species. The snowflake
hyssop grows quite slowly and is very easy to keep but it requires good lighting.
Size: 30 cm.