SIZE
The biggest unbranched inflorescence
The bloom is a spike carrying many male and female flowers, wrapped in a frilled spathe. RBGE says the tallest on record reached 3.73 m at Cibodas Botanic Garden in Indonesia.
Follow a bloomA BOTANICAL TITAN
Years to grow,
days to bloom.
The titan arum saves up for years, then spends it all at once.
UP TO 3.7 M open for days
≈ 11°C Spike surface above room temperature
- Not one flower but many
- Heat carries the smell
- Endangered in the wild
- A giant built for carrion insects
Native to the rainforests of Sumatra, Amorphophallus titanum stores energy in a huge underground corm. When it finally blooms, the central spike warms to around body temperature and the smell of rotting flesh draws in carrion insects.
THE SHORT ANSWER
A giant cluster,
not a giant flower.
Three things that make the titan arum odd.
Size, heat and smell.
HEAT AND SMELL
A warm spike that smells of death
During blooming the spadix heats up to human body temperature. A 2024 study found the main odorants are sulfur compounds also given off by decomposing bodies.
See the numbers
THE LONG WAIT
Years of leaves first
Plants take about 7 to 10 years to reach flowering size. Until then a single leaf, which can grow over 6 m tall, feeds an underground corm.
How it growsA BLOOM, STEP BY STEP
What is happening
right now?
Pick a moment in a titan arum's bloom. The bar shows how much is going on: heat, smell and pollination activity.
Based on the Royal Botanic Garden Edinburgh's notes from its own flowerings and the US Botanic Garden.
FOUR STAGES OF A TITAN
From corm
to corpse flower.
A titan arum spends most of its life as a single leaf and an underground store. The bloom is the brief payoff.
Leaf
One huge leaf on a mottled stalk makes food. RBGE says a leaf can reach 6 m or more.
Corm
The food is stored in an underground stem called a corm, which can weigh well over 100 kg.
Bloom
When enough energy is stored, often after several years, the plant sends up a bloom instead of a leaf.
Rest
After blooming, the plant usually needs time for leaf growth and dormancy before flowering again.
TWO NUMBERS WORTH KNOWING
Built for a
brief, hot show.
One figure on how hot the spike gets,
one on what it keeps underground.
≈ 11°C
Spike surface above room temperature
On the night of peak heating, researchers measured the outer surface of the bloom's central spike at about 11 °C above the room. The heat is thought to help spread the smell.
HEAT · PNAS NEXUS 2024
153.95 kg
Weight of one corm, 2010
The Royal Botanic Garden Edinburgh's corm weighed 153.95 kg in 2010, the largest ever recorded, and has since grown too heavy to lift and weigh.
STORAGE · RBGE
From Zulfiqar et al., PNAS Nexus (2024), and the Royal Botanic Garden Edinburgh's titan arum FAQ (2019).
WHY IT SMELLS
Chemistry of
a rotting smell.
A 2024 study in PNAS Nexus confirmed that the main odorants are dimethyl disulfide and dimethyl trisulfide, sulfur compounds that also come from decomposing bodies. It also found putrescine, a compound linked to rotting flesh, as a previously unrecognised part of the smell.
In the wild the smell attracts carrion beetles, flies and sweat bees. The plant is listed as Endangered on the IUCN Red List because of habitat loss, and RBGE worked with Bogor Botanic Garden in Indonesia to reassess its status.
Questions
Questions people ask
Is the titan arum the biggest flower in the world?
No. RBGE says the biggest true flower is Rafflesia arnoldii. The titan arum's bloom is an inflorescence, a cluster of many flowers, and it is the largest unbranched one in the world.
How often does a titan arum flower?
Plants take about 7 to 10 years to reach maturity, and a 2024 study says flowering typically happens about once every 5 to 7 years. RBGE's mature plant has flowered every two years.
How long does the bloom last?
Only a few days. RBGE says the spathe opens for 2 to 4 days, and the US Botanic Garden describes the plant lasting about 2 days at full bloom before collapsing.
When did it first flower in Britain?
It first flowered in cultivation at the Royal Botanic Gardens, Kew, on 22 June 1889, from seed collected in Sumatra by the Italian botanist Odoardo Beccari in 1878.
What is the titan arum related to?
It belongs to the arum family and is related to the Swiss cheese plant, the peace lily, the calla lily and the British native cuckoo-pint, also called Lords and Ladies.
Where the facts come from
Updated
- Royal Botanic Garden Edinburgh: Amorphophallus titanum, about the plant
- Royal Botanic Garden Edinburgh: Amorphophallus titanum frequently asked questions (2019, PDF)
- United States Botanic Garden: Titan Arum
- Zulfiqar et al. (2024) Molecular basis for thermogenesis and volatile production in the titan arum, PNAS Nexus