Spade-Leaf Sword

About

Echinodorus cordifolius is one of the largest swords in the trade, a marsh rosette ranging from the southern and southeastern United States through Mexico and Cuba into northern South America, where it usually grows emersed in swamps, pools, ditches and shallow lake margins. In a tank it builds a fountain of broad, ovate to heart-shaped blades carried on long, obvious petioles - 30-50 cm tall and 20-40 cm across, a solitaire for the background of a roomy, deep tank. Its failure mode is the opposite of a crypt melt: it does not dissolve, it leaves the water. Under intense light, a long photoperiod and rich nutrients it switches to floating and emergent aerial leaves while the submerged foliage dies back - and flowgrow is blunt that this limits the plant's suitability as an aquarium plant, filing its use as 'halb-emers (offene Becken)', semi-emersed, for open tanks. The catch you cannot see at the till is that suitability varies by population: in some forms the escape happens very soon and those plants belong in an open tank, while other populations are noticeably easier to hold underwater - and nothing on the label tells you which one is in the pot. Flowgrow goes further and warns that several different plants circulate under this name, not all of them this species; some are Echinodorus floribundus (also broad and heart-leaved, but its inflorescences stay upright longer and do not invariably carry plantlets, and its leaf tissue shows dots rather than dots and dashes), and Echinodorus hybrids sold under the label cannot be ruled out. The countermeasures for submerged culture are short-day lighting with a continuous dark phase of more than 12 hours and pinching out long-petioled leaves as soon as they appear - a photoperiod that fights most other plants in the tank. The gentler route is buying the 'Fluitans' form, which Tropica describes as less likely than other round-leafed varieties to grow up over the surface, spreading large leaves just beneath it instead; how lenient it actually is, is contested - Tropica rates 'Fluitans' low light, low CO2 and medium growth, while Aquasabi rates the same cultivar medium light and fast growth, against flowgrow's medium-to-high light and fast growth for the species. Cultivars differ in size too: 'Harbich' stays a compact, hard-leaved 25 cm or so, while 'Harbich Red' - sold in the US as 'Hadi Red Pearl' - has a disputed size, Dennerle giving up to 40 cm and Aquasabi's own 'Hadi Red Pearl' entry describing a plant hardly exceeding 10 cm, reaching about 20 cm high and 40 cm wide only when generously fed, which is reason to suspect the two trade names do not always cover the same plant. Its young leaves do open reddish and mature green - a trait of new growth on that cultivar, not something extra light or iron will spread over the plant - though Aquasabi notes even plain 'Fluitans' can show slightly reddish new leaves. In the shop it is confused with the Amazon sword, Echinodorus grisebachii, already in our catalogue: that one has very narrow, slightly sickle-curved lanceolate blades and normally stays submerged, exceeding 60 cm underwater, while cordifolius carries broad blades on distinct petioles and actively strives out of the tank. Judge by petiole and blade width rather than by the heart-shaped notch: flowgrow notes the traded forms vary, some with rounder, strongly cordate submerged leaves and others elongate with a barely cordate base. Emersed-grown pots arrive with round, hairy land leaves that are shed underwater and replaced by much narrower submerged foliage.

Care

Give it a tank at least 50 cm tall and a nutrient-rich substrate or root tabs - like other Echinodorus it benefits markedly from substrate feeding. To keep it underwater, run a short photoperiod with an unbroken dark phase of over 12 hours and remove long-petioled leaves the moment they appear, or choose the 'Fluitans' form; even then flowgrow rates submerged suitability as population-dependent, so accept that some plants sold under this name will only ever settle in an open tank. Expect emersed pots to shed their round hairy leaves before regrowing much narrower submerged ones.

Diet

A root feeder: like other Echinodorus it benefits markedly from nutrients supplied by the substrate, so an enriched base or root tabs under the crown are the main lever - no cited source claims growth outright stalls on a lean bottom, only that substrate feeding helps a great deal. Water-column dosing and CO2 (flowgrow's 10-40 mg/l is a benefit band, not a requirement) accelerate what the roots are already funding.

Frequently asked questions

What water parameters does a Spade-Leaf Sword need?

Spade-Leaf Sword does best at 15–30 °C (59–86 °F), pH 5–8 and a general hardness of 0–18 °dGH.

Where should Spade-Leaf Sword be placed in the aquarium?

Spade-Leaf Sword works best at the back of the tank and reaches around 50 cm.

Is the Spade-Leaf Sword suitable for beginners?

Spade-Leaf Sword sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.

Sources

• Flowgrow Wasserpflanzen-Datenbank — Echinodorus cordifolius (Herzblättrige Schwertpflanze)
• Tropica — Echinodorus cordifolius 'Fluitans' (073D)
• Aquasabi — Echinodorus cordifolius "Fluitans"
• Dennerle Plants — Echinodorus cordifolius 'Harbich Red' (169)
• Aquasabi — Echinodorus 'Hadi Red Pearl'
• Aquarium Gardens — Echinodorus Harbich
• Flowgrow Wasserpflanzen-Datenbank — Echinodorus grisebachii 'Amazonicus'