17 November 2021
What’s happening in the First Creek Wetland’s ‘settlement’ pond?An alga has been growing there that hasn’t been recorded in Adelaide for many years.
Location: Amazon Waterlily Pavilion, Adelaide Botanic Garden (F8 on the map)
Date and time: Open daily throughout summer.
Cost: Free entry.
COVID-19 safety: Please note that the display is visible from both inside and outside of the pavilion. Visitors over the age of 12 are required to wear a facemask while inside the glasshouse, as per government requirements. Please use the QR code to check in if you go inside the glasshouse and adhere to capacity limits listed on the building.
Titan arum is an endangered plant from the rainforests of Sumatra, Indonesia.
In this unusual display, you can see a sample of our behind-the-scenes collection in various stages of (non-flowering) growth.
This unusual plant has two life-cycles: a leaf cycle and a flower cycle. We are displaying the leaf cycle of the plant.
Please note: there is no flower on display at this time.
Titan arum has an annual leaf cycle that can last for up to ten years.
During this time, it will grow into a tree-like structure and get busy making energy to store in its underground tuber.
It grows very quickly, so come back to see their progress again!
After about 12-18 months, the plant will collapse and lay dormant for up to a year before it grows into a tree-like structure once again, giving another energy boost to its tuber below.... or it will start a flower cycle if it has enough energy.
While this plant may look like a tree, it's actually a single leaf. The trunk-like structure is called the petiole and it has branching leaflets at the top.
It has markings on the stem that are visually similar to lichen - a possible tactic to dupe passing herbivores into thinking it is a hard trunk, and not a juicy, tender meal.
It's getting ready to produce one almighty flower.
Titan arum's tubers can be as heavy as 75Kg. The heaviest ever recorded was a whopping 150Kg!
Before 2018, these plants were listed as a vulnerable species. Sadly, they have become even rarer in the wild since then and are now listed as an endangered species. Threats include habitat loss, theft and fire.
This species (scientific name: Amorphophallus titanum) is cultivated in botanical gardens around the world and is the focus of intensive research efforts to better understand the biology and the needs of this plant.
At the Botanic Gardens in South Australia, we have a large collection of Titan arums in various stages of growth. They are being grown as part of the world-wide conservation efforts to preserve this remarkable plant.
Our expert Horticultural Curator, Matt Coulter, has been able to reproduce the plants and create ideal conditions to encourage flowering. As a result we have had nine plants flower since we started the conservation work, and we also have frozen pollen.
After around seven to ten years, a plant will produce a flower for the first time. Following that, it may flower every two to five years in cultivation, or less frequently in the wild.
Titan arum produces what looks like a huge flower that can reach more than 2m tall!
But, the dark crimson petal-like structure is actually a modified leaf, and the pointy part in the middle is called the spathe. At the bottom of the spathe, hundreds of the tiny real flowers are hidden.
The plant is famed for its revolting smell, which has been likened to smelly feet, stinky cheese and dead animals - hence its nickname of the Corpse Flower. The pointy spathe is where the bad smell is produced.
Please note that there is no flower on display at this time.
It's a tactic to attract pollinators who just love feasting on rotting flesh: flesh flies, carrion beetles and sweat bees.
The plant only produces the smell at night - which is when these insects are out and about - but it only smells for the first two nights.
In their hunt for a meal, pollinators travel to the plant. If they are already covered in pollen from an altogether different plant, they will dust it onto the female flowers, which open on the first night. This is where the seeds are made.
On night two, the male flowers open and expose their pollen. Insects get covered in the pollen and take it to another stinky plant, which hopefully has some female flowers open.
This means that for pollination to be successful, plants need to flower two or three days apart.
The smell is strong enough to spread a long distance - as far as 5km - so it is detected by insects a long way away.
Once fertilised, the flowers will start to make seeds which will be covered in juicy red fruit in about nine months' time. Rhinocerous hornbill birds love to gobble them up, then poop out the seeds somewhere else in the forest, giving the plant a chance to grow elsewhere.
After a few days of blooming, the inflorescence of Titan arum will start to collapse, eventually leaving just the the berry-like fruits on display.
If the plant sets seed, it will likely die. However, if the plant does not set fruit, it will then become dormant again, with the tuber waiting to start a new leaf cycle once again.
In cultivation, for Titan arum to produce seed, its plants need to be hand-pollinated with pre-frozen (and then defrosted) pollen from a different plant.
The last flower that was able to go on public display was in October 2018, when more than 10,000 people came to get a whiff of this famed flower.
There have been more flowers since then, but due to COVID-19 limitations it has not been possible to put them on public display.
There are some plants in the collection which we think may flower in the next few years.
There are some clues to spot and our experts are constantly on the look out for signs.