This will be the first time that a titan arum has flowered in Scotland.
The plant, which has the heaviest corm ever recorded (153.9kgs). Staff have nurtured the plant for 12 years.
Senior horticulturist Sadie Barber, who was gifted the corm in 2003 by Hortus Botanicus in Leiden, Netherlands, said: "The plant has being growing and preparing for this moment all its life. When the huge inflorescence finally opens it will be at its best for one to two days. As well as the biggest, (growing at a rate of up to 17 cm per day to reach up to three metres tall), the bloom is arguably also the smelliest – with an odour likened to rotting fish.’’
Successfully bringing the titan arum to the point of flowering has involved replicating the conditions it would experience in the rainforests of Sumatra. The Lowland Tropics House provides the required high humidity and temperatures. During the day the temperatures are between 21-25 degrees centigrade, and by night above a minimum of 19 degrees centigrade with about 80 per cent humidity. The 1,000 litre pot is watered with a high potash liquid fertiliser (tomato food) and care is taken to avoid waterlogged conditions as this could cause the corm to rot. Often an Amorphophallus titanum will die after flowering, but with careful cultivation a plant can continue to produce more leaves or flowers in subsequent years.
In 2010 staff at the garden had to borrow scales from Edinburgh Zoo to weigh the corm which at £153.9kgs, smashed the existing world record of 117kgs, held by Bonn Botanic Gardens, Germany, by 36.9kgs. At the time of the weigh in it had grown from the size of an orange to measuring 952mm wide and 426mm high with a circumference of 280cm.
More work is needed to establish the conservation status of titan arum in the wild. It is only known from the Bukit Barisan range of mountains in West Sumatra and is classified as Vulnerable (V) on the 1997 IUCN Red List of Threatened Plants.
Sumatra is part of RBGE’s ongoing research in Southeast Asia on diverse tropical plant families including the gingers (Zingiberaceae), begonias (Begoniaceae), Gesneriaceae and tropical trees in the Sapotaceae and Malvaceae.
Amorphophallus titanum facts:
- Seed was originally sown in Hortus Botanicus Leiden (Netherlands) in 2002, making RBGE plant 13 years old
- RBGE received the resultant corm in 2003, when it was the size of an orange
- In its 12 years at RBGE the corm has produced seven leaves, the tallest of which was 4.2m in 2011
- The last leaf grew from August 2013 to April 2015
- It is growing in a 1,000 litre pot in the Lowland Tropics glasshouse, which is kept at 21-25°C during the day (minimum 19°C at night) and approximately 80 per cent humidity
- The free-draining compost consists of bark, pumice, sand, charcoal, perlite, slow-release fertiliser
- The last time the corm was measured (2010) it weighed 153.9kg, making it the largest ever recorded (although not official Guinness World Record)
- In 2010 we took leaf cuttings, which have produced new corms that are currently growing at RBGE
- The new bud emerged on 12 May 2015
- The top of the corm lies 12cm under the soil surface