Cryptocoryne cordata var. siamensis

The Siamese water trumpet is a variety of Cryptocoryne cordata from the south of Thailand. There it occurs in calcareous, shaded flowing waters, in contrast to the type variety Cryptocoryne cordata var. cordata, which occurs in acidic, soft waters on the Malay Peninsula. The variety siamensis is very variable in size, leaf shape and colouration, and in aquarium culture there are different forms. For example, the large, broad-leaved "Cryptocoryne blassii" was popular decades ago as an undemanding aquarium plant, but has become rare in the hobby today.
The form we offer (Dennerle abbreviation C30) is smaller and narrower-leaved than the form "blassii". It has lanceolate, somewhat shiny leaves with an attractive dark line pattern and reddish-purple underside. Especially under intense light, the plant hardly grows taller than 10 cm for a long time, with a spreading habit. After a long time, especially in low light and with plenty of nutrients, it can grow over 20 cm tall. The petioles are then often longer than the leaf blades, which are about 7 - 8 cm long. Through underground runners, Cryptocoryne cordata var. siamensis can form a lush, dense stand over time.
In shallow water or in emersed culture, inflorescences with a long tube and yellow spathe blade may appear.

This slow-growing Cryptocoryne can be kept in soft to hard water. The Siamese water trumpet is particularly suitable for aquariums with fish and without added CO₂, which are only dimly to moderately lit. However, it also thrives in intensive light and with added CO₂. Nutrient supply via the substrate is very beneficial for its growth. The optimum temperature range for this tropical aquatic plant is between about 22 and 28 °C. Propagation is done by cutting off young plants that develop on the underground runners.

This relatively small form of Cryptocoryne cordata var. siamensis makes an interesting accent as a younger plant in the foreground to midground with its spreading, dark marbled leaves. Older, taller stands fit better in the middle to background. The Siamese water trumpet is versatile and also a suitable plant for tropical river biotope aquariums. In open, shallow tanks, you can count on its attractive inflorescences with yellow spatha.