Blyxa japonica is an obligate aquatic plant often found in stagnant, shallow pools and marshes as well as in slow moving, iron-rich forest streams in tropical eastern Asia. It can also be found in man-made habitats (such as rice paddies) throughout its range. It has become a staple in the planted aquarium hobby due to its attractive grassy, hedge-like appearance and should be easily obtainable from many internet retailers or through trading.
This Blyxa species is not too difficult to grow if its basic requirements are met: intense lighting in the 2-4 watts per gallon range, CO2 injection, and a fertilization regimen including nitrate, phosphate, potassium, and micronutrient supplementation. If conditions are to its liking and lighting is intense, the leaves of B. japonica will develop golden and reddish hues and the plants will exhibit more compact growth. If it does not receive enough lighting, however, B. japonica will become taller, lankier, and greener. This plant produces an impressive root system and appreciates a nutritious substrate. If phosphate levels are kept high (1-2 ppm), this species will continuously produce small white flowers on long, thin stalks.
Despite its appearance, B. japonica is actually a stem plant growing on a densely foliated, short stem. Unlike other grassy mid- to foreground plants, it is not nearly as invasive since it does not produce long runners. Instead, it produces basal side shoots which can easily be divided from the main plant with a sharp pair of scissors. Replanting these side shoots can be a bit problematic as they are very buoyant and tend to float. However, they take root quickly once in place.
B. japonica has recently been popularized by Takashi Amano’s ‘Nature’ layouts, where he utilizes its dense growth habit and grass-like appearance to form attractive greenish to golden tussocks in the midground. It forms an excellent contrast with small-leaved foreground plants such as Glossostigma elatinoides in aquascapes lacking taller plants.
This plant requires bright light. Iron dosing along with regular fertilization will make this plant take on a maroon coloration.
Hardiness: Moderate
Light Needs: Medium
Plant Structure: Stem
Family: Hydrocharitaceae
Genus: Blyxa
Region: Asia
Location: Tropical Asia
Size: Height: 7-15cm (3-6in)
Growth Rate: Medium
Can Be Grown Emersed: No