It is hard to mistake a tacca for anything else: its deep purple, almost black flowers are framed by large wing-like bracts and long thread-like whiskers. That is why it is called the bat flower or black lily. Tacca comes from the tropics, so indoors it needs warmth and humid air.
The genus Tacca belongs to the yam family and grows in the tropical forests of Southeast Asia, Africa and Oceania. It is a perennial with large leaves on long stalks and a rhizome. One species, Polynesian arrowroot (Tacca leontopetaloides), has tubers that are eaten in the tropics, but only after special processing: raw they are bitter and inedible.
Species grown indoors
Black bat flower (Tacca chantrieri) has dark maroon to almost black flowers and bracts with long dark whiskers.
White bat flower (Tacca integrifolia) has large white or pale purple bracts above dark flowers and very long whiskers.
Use a loose, airy mix: orchid or aroid compost with added peat and perlite.
Feed every 2–3 weeks from spring to autumn with a flowering-plant fertiliser at half strength.
Growth slows in winter: water less and stop feeding, but never let the rhizome dry out.
Flowering
Tacca usually flowers in summer. A tall stalk carries a cluster of flowers surrounded by bracts and whiskers that can be several tens of centimetres long. If it does not flower, it usually lacks warmth, humidity or nutrients.
The easiest method is to divide the rhizome when repotting in spring, making sure each piece has a growing point. It can be grown from seed, but germination is slow and uneven.
Common problems
Dry leaf tips: dry air.
Leaves yellowing and rotting at the base: overwatering and cold.
Because of its dark, almost black flowers and large bracts. It is not related to lilies.
Can I keep a bat flower above a radiator?
Better not: hot, dry air quickly damages the leaves. Move the pot and raise the humidity.
Author: Maria Svitlovir
Graduated from Taras Shevchenko National University of Kyiv, Institute of Biology and Medicine (2001). BSc in Biology, MSc in Horticulture. Writes about plants, works at a garden centre selecting and repotting plants, and contributes to plant reference guides.