Range and localities [?]: probably Thailand
Hygrophila sp. ‘Bold’ is a strikingly coloured Hygrophila species that appeared in aquaristics in the USA in 2006 for the first time. As it seems, this plant is not yet in cultivation in Europe.
It is not clear at the moment which species it belongs to and in which area it originates, but it could be native to Thailand. The variations of many plant species depend very much on the conditions they live in, however, Hygrophila sp. 'Bold' is among the most variable aquarium plants, with a plasticity that is simply astonishing.
It is often confused with another new plant, Hygrophila sp. 'Tiger'. Both may have a gridlike pattern on their leaves, however, submersed H. sp. 'Bold' has a slightly create leaf margin and somewhat narrower leaves. Their tip is not as obtuse as that of H. sp. 'Tiger'. Under intensive light and ample micronutrient fertilisation, H. sp. 'Bold' can assume an intensive reddish brown to purple colour, and it forms relatively short internodes. A similar effect can be observed in tanks with mineralised soil as substrate (set up according to the methods of Aaron Talbot and Tom Barr). Under "standard" conditions in the aquarium, the leaves are of a more brownish colour, and their gridlike pattern is more pronounced, the internodes grow out longer. It grows well even without CO2 injection and strong lighting, and thus H. sp. 'Bold' is a good alternative to Hygrophila polysperma, regarding adaptability as well as growth habit.
Emersed cultivation is very easy, and the plasticity of this plant is as striking in the land form. Young emersed specimens often have many glandular hairs and show a reddish brown colour, whereas older plants are distinctly less hirsute and mostly green. Other than many Hygrophila species, the flowers of H. sp. 'Bold' grow densely together with the bracts in a beautiful spike at the end of the flower stalk. The width of the emersed sprout, measured from leaf tip to leaf tip, may be up to 20 cm, so quite a bit of space ought to be reserved for this plant.
At the moment, Hygrophila sp. ‘Bold’ is not available in trade, however, it can (in the USA) quite easily be obtained by trading with other aquarists. It is easily confounded with Hygrophila sp. 'Tiger', so check the plant's identity.
Hygrophila sp. 'Bold' is just as undemanding as “normal” Hygrophila polysperma and still grows in the aquarium under moderate lighting and without CO2 supply. With plenty of light and a good nutrient supply, however, it shows more attractive colouration (see “General”). Its very fast growth makes frequent trimming necessary. Like other stem plants, it is propagated by top and partial cuttings or by separating and replanting side shoots.
Emersed cultivation presents no difficulties, and the plasticity of this plant also becomes evident in the land form. Young emersed specimens often have many glandular hairs and are often reddish brown, while older plants are considerably less hairy and mostly green. Unlike in many other Hygrophila species, the flowers of H. sp. 'Bold' appear densely crowded together with the bracts in a pretty spike-like inflorescence at the end of the stem. The width of the emersed shoot, measured from leaf tip to leaf tip, can be up to approx. 20 cm, so that quite a lot of space must be provided for the plant.
Hygrophila sp. 'Bold' can be regarded as an alternative to "normal" Hygrophila polysperma, both in terms of its adaptability and its growth form. With its narrow, variable leaf shape and red-brown colouring and leaf markings, however, it is more conspicuous. One must also note that the plant partly tends towards "wild", creeping to ascending growth. Because of its size it needs quite a lot of space and is particularly recommended as a group in the midground or background of taller tanks (over 40 cm). As a very fast-growing, undemanding plant, this Hygrophila is well suited to the initial planting of newly set-up tanks.
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[widget=aquaticplants/hygrophila-sp-bold]Hygrophila sp. 'Bold'[/widget]