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Hydrilla is a genus of submerged freshwater aquatic plants, usually treated as one species, Hydrilla verticillata (waterthyme), native to Asia, Africa and Australia. It grows fully underwater and spreads aggressively where conditions suit it.
Hydrilla (waterthyme) is a genus of aquatic plants, usually treated as containing just one species — Hydrilla verticillata, but some botanists divide it into several species. It is native to the cool and warm waters of the Old World in Asia, Africa, and Australia, with a sparse, scattered distribution; in Australia it occurs from the Northern Territory to Queensland and New South Wales.
The stems grow up to 2 m long. The leaves are arranged in whorls of two to eight around the stem, each leaf 5–20 mm long and 0.7–2 mm broad, with serrations or small spines along the leaf margins; the leaf midrib is often reddish when fresh. It is monoecious (sometimes dioecious), with male and female flowers produced separately on a single plant; the flowers are small, with three sepals and three petals, the petals 3–5 mm long, transparent with red streaks.
Hydrilla verticillata is negative allelopathic to the common hornwort (Ceratophyllum demersum) and prickly hornwort (C. muricatum), that is, it produces compounds that inhibit growth of the latter two species.
Text excerpted from the Wikipedia article Hydrilla by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
