Amorphophallus ferruginosus
Rusty voodoo lily
Overview
Amorphophallus ferruginosus is a tuberous perennial in the Araceae, described as a species in 2012 from material collected in Laos. Each growing season a single leaf rises 24-36 inches (60-90 cm) from an underground tuber with a knobbed, warty brown surface. The petiole is rusty iron-red to red-brown and marked with large pale silver blotches. The blade divides into three primary segments that subdivide into green leaflets, spreading 18-30 inches (45-75 cm) across. Flowering occurs on a short peduncle 4-8 inches (10-20 cm) tall, coloured pink to violet, which rises from the dormant tuber ahead of the leaf. The spathe is white and forms a cup 3-6 inches (8-15 cm) tall around a white spadix. Scent released while the inflorescence is open has been recorded as kerosene with a sweet note, and as overripe stone fruit. The plant is polycarpic, flowering in successive years rather than once in its life. Foliage dies back and the tuber rests through winter. Frost damages the leaf and tuber, so plants are grown under cover outside tropical and subtropical climates, and tubers rot in mixes that stay wet during dormancy.
Native Range
Recorded from Laos, where the plant was collected and later described as a new species in 2012. Habitat is seasonally dry tropical forest with a marked dry season, through which the tuber rests underground. Records outside Laos are few.Suggested Uses
Grown in containers of 3-5 gallons (11-19 L) under glass or in shadehouses in temperate regions, and in open ground in tropical and subtropical gardens under light shade. Planted in aroid and shade-plant collections alongside Arisaema and Typhonium at 18-24 inch (45-60 cm) spacing. The tuber is not used as food, in contrast with the cultivated A. konjac.How to Identify
Appearance
Size & Dimensions
Height2' - 3'
Width/Spread1'6" - 2'6"
Bloom Information
Flowering comes from the dormant tuber in spring, ahead of leaf emergence, and lasts 2-4 days from spathe opening to collapse. Scent is released during the first night and through part of the following day. Plants flower in successive years once the tuber reaches flowering size, rather than at multi-year intervals. Tubers below flowering size produce a leaf and no inflorescence.
Detailed Descriptions
Flower Description
white spathe and spadix on a pink to violet peduncleFoliage Description
green leaflets on a rusty iron-red petiole with pale silver blotchesGrowing Conditions
Sun Requirements
Requires 2-5 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Tubers are potted in a free-draining mix of bark, perlite, and loam, with the growing point 1-2 inches (2.5-5 cm) below the surface. Growth restarts in spring at temperatures above 68 degrees F (20 degrees C); water is given as the shoot appears and increased as the leaf expands. Light shade suits the leaf, and direct midday sun scorches the blade within a few days. Water is withdrawn as the leaf yellows in autumn, and the tuber is held dry at 55-65 degrees F (13-18 degrees C) through dormancy; tubers held wet and cool rot within a season. Feeding at half-strength balanced fertiliser every 2-3 weeks through leaf growth builds tuber size, with tubers gaining 30-60 percent in weight over a season. Spider mites and mealybugs colonise the petiole under glass where air is dry.Pruning
The leaf is left in place until it yellows and collapses in autumn, since the tuber draws reserves from it through senescence; cutting the leaf while green reduces tuber weight for the following season. Collapsed petioles are cut at the tuber surface once dry. Spent inflorescences are removed at the base after the spathe withers, unless seed is wanted. Offsets forming beside the parent tuber are separated during dormancy.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
fall
Container Growing
Suitable for container growing
Minimum container size: 3 gallons