Aquarius cordifolius

Lore & Background

Aquarius cordifolius is a perennial herb with stout rhizomes, reaching up to 100 cm in height. Its leaves are typically emersed, with submersed leaves mostly absent; the petiole is 5–6-ridged and 17.5–45 cm long, and the blade is ovate to elliptic with translucent markings, measuring 6.5–32 cm by 2.5–19.1 cm. The inflorescence is a raceme of 3–9 whorls, each with 3–15 flowers, decumbent to arching, often proliferating, and up to 62 cm long. The sepals have 10–12 papillate veins, a distinguishing feature. The plant blooms from spring to fall and is found in marshes, swamps, ditches, and ponds.

Reader's Guide

Aquarius cordifolius is easily cultivated in neutral to soft water with tropical to sub-tropical temperatures, requiring a rich substrate and good light. It is common in the aquarium trade, though most plants sold are grown emersed on farms. When submerged, leaves may die off before underwater leaves develop. In the aquarium, it serves as a background specimen plant but will outgrow smaller tanks; removing floating leaves helps keep it smaller. It needs a large, deep aquarium to grow properly, and CO2 infusion promotes stronger growth. A heavy feeder, it benefits from a rich substrate including clay. Emersed plants are prone to aphid attacks. It can be grown outdoors in warmer climates but does not tolerate frost. Several forms exist: Tropica Marble (Marble Queen) has marbled leaves that may fade in low light; ovalis is a smaller, orbiculate form reaching about 35 cm tall and 30 cm wide, suitable for small aquariums; and ssp. fluitans is fast-growing, reaching about 40 cm, and tends to stay submerged with large leaves just under the surface.

Did You Know?

• It is the only species in its group with arching to decumbent inflorescences.
• The sepals have papillate veins, a unique feature among related species.
• It blooms from spring to fall in its natural habitat of marshes, swamps, ditches, and ponds.
• The plant can be grown emersed or submersed, but emersed plants readily produce flowers and seeds.