One of the most impressive succulents, Agave americana, has started flowering at Trebah Garden in Mawnan Smith.

Known to some as the century plant, because it is thought to flower only once every 100 years, this is a little misleading as it usually flowers after 20 to 30 years of storing enormous food reserves in its leaves. Once the agave flowers it then dies.

The flower spike which is now emerging will in a short space of time attain a height of up to nine metres tall with a many-branched stalk covered in clusters of yellow flowers up to ten centimetres long. The seed pods will later follow with fruits up to five centimetres long, full of glossy black seeds.

The plant has moved location a few times during its life at Trebah. First planted on the original rockery it was seen as such a feature that when the area was cleared to build the new visitor centre in 2001, a new home had to be be found for it.

Due to its size, even back then, it had to be craned out and then lowered back into position in the new rockery on the top lawn of the garden. The already evident spike is growing at a rate of approximately a 30 centimetres a day.

Head gardener, Darren Dickey said: "I have worked at Trebah now for 25 years. I was promoted to head gardener in 2002 and coincidentally at that time was heavily involved in the landscaping and planting around the new visitor centre including the creation of the new rockery area.

"When I first started at Trebah in 1991 the old rockery display was well established with big specimen plants including the agave in question. I have been waiting 25 years for this moment and I am very excited."

Visitors should be able to witness the Agave in bloom until at least the end of November.