by Ole Pedersen, Troels Andersen and Claus Christensen
Utricularia graminifolia (Tropica No 049B)
belongs to the most interesting water plants. It is carnivorous and
creates an attractive green carpet in the foreground within a
couple of months. Utricularia graminifolia may be
difficult to start up but once it has gotten a firm grip in the
aquarium, it offers a unique experience for the aquarist. The tiny
trapping devices may inspire long discussions among family members
and friends as carnivorous plants always stimulate people's
Bladderworts are all carnivorous plants and many of them are
associated with water. The genus name "Utricularia" refers
to the bladders (trapping devices) whereas the species name
"graminifolia" refers to the grass-leaved leaves. The grass-leaved
leaves are exactly what distinguish it from the other approximately
210 species of bladderworts that have been described so far. The
tiny grass-leaved leaves form an imbricate structure of freshly
green leaves, which normally covers the bladders that are formed on
the rhizome and the midribs. It flowers when it grows
Tropica grows Utricularia graminifolia emergent and it is supplied on either stone wool or coir discs. When planted in the aquarium, the clod should be divided into 6 to 8 smaller pieces and planted with a distance of 5 cm in the foreground of the aquarium or on a slope in the aquascape. It is important to keep about 1 cm of the coir or stone wool in order to provide good anchoring of the plants. Using tweezers to insert the tiny blocks of plants makes the entire process of planting much easier. To begin with, Utricularia graminifolia should be offered relatively low light but after the initial 6-8 weeks, where after the plants have obtained a firm hold in the aquarium, the light may be increased. At this point in time, the tiny blocks have now been transformed into a continuous grass-like carpet and this is the time where PLANT NUTRITION liquid should be supplied in order to prevent iron and manganese deficiencies. Our experience with Utricularia graminifolia shows that it is doing best at a pH of 6.8 to 7.0 in water of 7-10 dKh hardness. Fertilization with CO2 is not required but if supplied, the growth is stimulated significantly. Although the commercially available variety is sturdier that the wild type, the initial phase after planting may prove critical since the Utricularia graminifolia is sensitive to environmental changes. Thus, make sure that the recommendations are followed and keep other fast-growing plants out of the new patches with Utricularia graminifolia until the plants are well established in the aquarium. Utricularia graminifolia is relatively fragile and thus, it should not be kept with fishes with burrowing behaviour.
Utricularia graminifolia in its natural habitat on the edge of a shaded stream in southern Vietnam. The plant grows partly submerged and partly emerged among the leaf litter.
Close-up of the trapping devices on Utricularia graminifolia that are used to catch crustaceans and ciliates. The animals contain nitrogen and phosphorous that can be used by the plant after the tissue has been dissolved by enzymes in the tiny traps. Photo by Oliver Knott.