Alocasia × amazonica 'Polly'

Where it comes from

Nowhere. It is a garden hybrid, and neither of the names on the label means what it looks like it means: not the Amazon, and not Africa either.¹

The parents are real and both Asian. Kew gives the cross as Alocasia longiloba × Alocasia sanderi² — longiloba ranging through Malesia,³ sanderiana endemic to Mindanao in the Philippines.⁴ So the plant’s ancestry is Philippine and Malesian, and the marketing is geography-blind in both directions.

The origin story worth correcting is the date. The hobby has this as a Miami invention of the 1950s, and there is a real document behind that: J. B. Reark’s 1953 paper on growing Alocasia in Florida carries a photograph captioned as a hybrid “produced by Mr. S. Mauro of Miami”.⁵ That much is in print. But Kew’s accepted name for this cross is Alocasia × mortfontanensis André, published in 1891 — and it treats A. × amazonica Reark as a synonym, and as not validly published.²⁶ The cross was first made in France, at Mortefontaine, about sixty years before Miami. Mauro appears to have re-made it, not invented it.

Two details the chain of blogs has added that the record has not: the first name “Salvadore”, and the nursery called Amazon Nursery from which the epithet is said to come. Those trace to one specialist page and its copies, not to three independent sources; even IPNI hedges, noting the plant is only believed to have originated in a Miami nursery.⁷⁸

‘Polly’ itself is later and better documented: a dwarf selection found at Silver Krome Gardens in Homestead, Florida, and attributed by its propagator to Denis Rotolante in 1993.⁹¹⁰

Naming and description

Which name is right depends on which authority you are asking, and both are defensible. Kew, ruling on botanical nomenclature, accepts Alocasia × mortfontanensis.² The RHS, ruling on horticultural naming, lists Alocasia × amazonica with name status “Correct” and gives it an Award of Garden Merit, with ‘Polly’ accepted beneath it.¹¹¹² This page keeps the name on the label and notes that the botanists’ version differs — which is the situation, rather than a fudge. One form that is simply wrong is “Alocasia amazonica” without the multiplication sign: it states a species that does not exist, and the RHS files it as a synonym.¹³

The difference between ‘Polly’ and the full-size hybrid is size, and it is substantial. The RHS puts × amazonica at 1–1.5 m with leaves to 60 cm, taking five to ten years;¹¹ ‘Polly’ at 0.1–0.5 m in one to two years.¹² NC State gives the hybrid 1–4 ft and ‘Polly’ up to about 2 ft.¹ Beyond size, no authority separates them: the claims that ‘Polly’ has rounder or narrower leaves come from hobby sources that contradict each other.¹⁰¹⁴

On temperature the RHS rates both H1A, a minimum of 59 °F (15 °C), while its own genus guide allows a winter floor of 50 °F (10 °C).¹²¹⁵ Reark, writing from Florida experience in 1953, put the damage thresholds below 50 °F (10 °C) and injury below 40 °F (4 °C).⁵

Fun facts

• It is not sterile, and a patent proves it. The standing explanation for why it never sets seed is that hybrids cannot. But the US plant patent for a sibling cultivar records its pollen parent as “the unpatented variety of Alocasia known as ‘Polly’”.¹⁶ The pollen works; somebody used it.
• The reason it never fruits on a windowsill is that its pollinators are missing. The flowers are protogynous — female phase first, pollen released only on the third day — so a single inflorescence cannot easily fertilise itself.⁵ In the wild the job is done by Colocasiomyia flies that spend the night shut inside the floral chamber; when researchers bagged inflorescences in fine mesh to exclude them, almost no fruit set.¹⁷ Nothing is wrong with your plant. The flies are in Asia.
• The toxicity is two mechanisms working together, not one. Aroid sap carries needle-shaped calcium oxalate crystals, and it also carries proteases. Tested separately in insects, each was weakly active; together they were far worse, because the crystals puncture the tissue and let the enzymes in.¹⁸ That is why the sting is out of proportion to the chemistry. In ordinary household exposure it means mouth and throat irritation lasting hours rather than anything systemic,¹⁹ but the dose matters: a 2025 case report on this exact hybrid describes a woman who drank 200–300 ml of liquid from the grated root and spent twenty days in hospital.²⁰
• One parent is critically endangered in the wild. Kew lists Alocasia sanderiana as Critically Endangered and endemic to Mindanao;²¹ it was listed on CITES Appendix I before being moved to Appendix II in 1992 and later deleted entirely.²² The plant sold in every supermarket has a parent that is nearly gone from the forest it came from, which is a strange and common combination.