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Giant penis plant is blooming at Hortus botanicus

The ‘Amorphophallus titanum’ at the Hortus botanicus Leiden is blooming. This Titan Arum, also known as the ‘giant penis plant’, last flowered in 2009.

You may be thinking: didn’t it flower last year? That was a different species, Amorphophallus decus-silvae. The penis plant that is now flowering is even bigger.

Female and male flowers

The penis plant in bloom

Amorphophallus titanum or the Sumatran giant arum is known and infamous for its immense inflorescence, which can reach three metres in height and gives off a pungent scent. First, a fleshy inflorescence (the spadix) enveloped in a sheath-shaped bract (the spatha) emerges, which opens after a few days.  Both male and female flowers grow in the inflorescence, and are located at the bottom of the spadix.  To prevent self-pollination, the female flowers open first. The male flowers follow two days later.

After flowering, a large single compound leaf emerges from the large underground tuber, which can reach a height of four metres.  After a growth period of almost one and a half years, the leaf dies, leaving only a tuber under the ground. and the plant rests for a few months. In the following years, the plant produces a new leaf. The leaf is always about twice as big as the previous leaf. With the leafy green and the sunlight, the plant produces food, which is stored in the tuber.  After about ten to fifteen years of this cycle, enough energy has been built up to start flowering again.


The name of the Amorphophallus titanium comes from the phallic-shaped spadix. Literally translated, it means ‘giant shapeless penis’. The titan arum is native to the rainforests of western Sumatra, where it grows in semi-shaded areas.  Nobody knows for sure how it is pollinated but this is probably by flies, because of its colour and scent, but it could also be beetles. Because its natural habitat is under severe pressure, the titan arum is threatened.

See the Hortus botanicus Leiden Instagram account to find out more about the plant:

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