Cryptocoryne tonkinensis

Care at a glance

Overview

Use it like a finer-boned balansae: a background or tall midground grass whose ribbon leaves reach for the surface and sway in flow. Plant it in a nutrient-rich substrate with root tabs, give it medium light and let it establish; CO2 is optional but noticeably improves density. It is slower than balansae and takes months to bulk up, spreading by runners into loose stands. The usual crypt rules apply: keep parameters steady, expect melt after planting or big water changes, and do not move it once settled. Like the whole crispatula group it handles hard, alkaline water well.

In the wild

Grows in northern Vietnam and southern China (Guangxi), in streams and rivers with strongly seasonal flow, rooted in sand and gravel. Like the rest of the crispatula group it is a rheophyte, spending high water fully submersed with leaves streaming in the current and flowering emersed as levels drop.

Good to know

A botanical variety of Cryptocoryne crispatula in the family Araceae, not a cultivar: var. tonkinensis (Gagnep.) N. Jacobsen, named for Tonkin, the old European name for northern Vietnam. It is one of the narrowest-leaved forms of the crispatula complex, with grass-like blades a few millimetres wide where var. balansae is broader and puckered. Flowgrow notes an even narrower plant from eastern Thailand was long traded under this name and is now described as var. kubotae, so shop plants deserve a second look.

Did you know

The varietal name comes from Tonkin, the colonial-era name for northern Vietnam. In a tank its millimetres-wide ribbon leaves are regularly mistaken for Vallisneria or a grass; the giveaway is the crypt habit, advancing in slow steps from runners instead of racing across the tank.

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