The blooming of Amorphophallus titanum in Auckland this week is an exciting first for New Zealand. Technically this "flower", coined the "Titan Arum" by Sir David Attenborough, is the world's largest "unbranched inflorescence" as it contains hundreds of tiny hidden flowers. The blooming of this plant is rare the world over and thousands queue to catch a glimpse.
At the time of writing, the staff at the Auckland Domain's Wintergardens don't know exactly when the plant will bloom. It may already be open and stinking out the tropical glasshouse by now.
The Titan Arum blooms only for a short while. It slowly opens in the evening, gives off a strong rotting flesh or "carion" smell in the hope of attracting pollinators, then it begins to close 24 hours later. It will likely collapse a couple of days after that.
The botany and the smell
The Titan Arum first flowered in cultivation at The Royal Botanic Gardens at Kew in 1889.
The stench was described by British botanist and former director of Kew Gardens Sir Joseph Hooker as smelling like "a mixture of rotting fish and burnt sugar, which turns your stomach over and makes your eyes run".
The plant is native to western Sumatra, and the Indonesian name for this plant is "bunga bangkai", which means corpse flower. This smell attracts carrion beetles and flies for pollination. The bloom also generates heat, which helps the smell travel further. If you plan to visit this giant wonder, bring a peg for your nose.
The plant is a member of the Araceae family, which includes the calla lily. The "bloom" has hundreds of small male florets and female flowers at the base of the spadix, which is a long, creamy yellow spike that looks a bit like a French bread stick.
This is surrounded by a "spathe" (a single bract or modified leaf) which, when open, is dark crimson to brownish purple, has a frilled edge and is pale green underneath. It can grow more than 3m tall and 1.5m wide and was once imagined to be a man-eater.
Flowering is no easy feat. It can take a corm (bulb) up to 10 years to build up enough energy and size to bloom and weighs in typically at 50kg. The corm at the Wintergardens weighed approximately 50kg a couple of years before blooming and is now 7 years old. The largest to date was 117kg at the Botanic Garden of Bonn, Germany.
The corm produces a large singular leaf which is branched and has lots of leaflets, giving it a tree-like appearance. Through photosynthesis, the leaf supplies sugars which become starch inside the corm. After the leaf dies back, the corm will rest for a while, then produce another leaf and the cycle continues. This process increases the size of the corm.
The Titan Arum was treated almost the same way as any plant in the Wintergarden tropical house, which reaches a humid 28C. It was grown in free-draining potting mix with a little slow-release fertiliser. During the growing phase, the plant was fed with the same liquid food that most of the tropical plants get. It was important to keep the corm dry in its dormant phase as they are susceptible to rot and nematodes. This plant started emerging from the corm on November 11, and the white spathe was visible by the November 18.
In need of protection
Deforestation and the loss of natural habitat in Sumatra are major threats to the plant. Botanic gardens around the world are working hard to find effective ways to keep the species producing viable seed in case its habitat is lost entirely. Unfortunately, the demand for palm oil has meant the increased destruction of the rainforests in Indonesia and the mass planting of oil palm plantations to feed this demand. To help protect this botanical marvel, avoid products containing palm oil, and forget buying kwila timber for your decking unless it is certified by the Forest Stewardship Council (FSC).
Visitors can see the plant at the Wintergarden's tropical glasshouse in the Auckland Domain between 9am-5.30pm daily, open until 7.30pm today. Free entry. Visiting hours may adapt if necessary. Turn your flash off before taking a photo.