Brisbane vs The Lilac Devil

By Chris Currie | 1 September 2026

For over 70 years, an aquatic invader regularly stalked Brisbane's waterways, bringing The River City to a literal standstill. This monster was not fearsome to look at, but it still threatened our way of life. This is the story of 'The Lilac Devil'.

An archival black-and-white photograph shows seven people gathered around a pond choked with flowering water hyacinths. In the foreground, two young boys sit in a small boat in the open water. Behind them, a dense mat of dark green leaves and light-colored blossoms covers the pond. Standing within the patch of weeds are three men: one on the left in a dark long-sleeved shirt and hat, one in the center crouching down, and one on the right in suspenders, trousers, and a wide-brimmed hat. Further back, on

The Brisbane River has always been a vital transport corridor. It links neighbourhoods and businesses and carries people across the city in their daily lives. For over 70 years, that routine was disrupted when 'The Lilac Devil' came to visit.

Water hyacinth (Eichhornia crassipes), a South American water weed – whose nickname comes from its attractive purple-blue flowers – is one of the most invasive plants in the world.

Its dense root system and astonishing speed of propagation mean it can double in size week by week given the correct conditions. Once fully formed, it can destroy native animal and fish habitats by consuming huge amounts of oxygen and providing a breeding ground for mosquitoes.

An oil painting of purple water hyacinth flowers in a glossy blue bowl, rendered with soft textures and muted lighting. Multiple tall stalks of blooming lavender-blue flowers with yellow-spotted upper petals rise from the dark bowl, surrounded by thick, fleshy green leaves with distinctive bulbous stems. One flower cluster droops to the lower right. The bowl sits on a reflective surface against a plain, neutral-toned background, with the artist's signature "V. LAHEY" in the lower right corner.

A watercolour of the 'beautiful but sinister water-weed' by Queensland artist Vida Lahey.

Originally bought to New South Wales as an ornamental plant in the 1890s, the water hyacinth quickly spread from Sydney’s Royal Botanic gardens up the east coast and by 1900 had brought Ipswich’s bustling Bremer River to a standstill.

An extraordinary image below from The Queenslander in 1908 shows Ipswich locals standing on a mat of water hyacinth some 'seventeen feet thick'!

An archival, grainy, black-and-white photograph shows a large group of men, women, and children standing amidst a dense field of leafy green plants on a hillside. In the foreground on the left, a man in a dark suit, tie, and light hat holds a white flower. Other individuals, some wearing hats or holding flowers, are scattered throughout the crop-filled field, while a steep, grassy hill rises in the background.

The “Lilac Devil” would inevitably make its way to Brisbane – especially after storms and cyclones – arriving in extraordinary quantities in the city reaches, transforming parts of the river surface into a thick, drifting barrier.

Items in State Library’s collections show the extent of the water hyacinth’s disruption. One memorable 1908 photograph from Toowong Reach shows a young boy sitting on the weed like a stool, his boat is unable to move through the water.

An archival black-and-white photograph shows a wide expanse of the Brisbane River, choked with a dense cover of water hyacinth. In the foreground on the grassy bank, four people are gathered around a small wooden rowboat. On the left, a child sits on the boat's edge under a leafy tree; another child sits inside the boat. A man in a hat and light-colored shirt leans against the boat's bow on the right, while a second man sits on the bank nearby. In the background, patches of open water are visible amidst the

Over the decades that followed, councils and landholders tried almost everything to bring it under control as the weed reappeared in creeks, lagoons and rivers. Plants were dragged out by hand, raked from banks, and hauled away in dripping piles that stank as they rotted in the sun.

During floods, mats of hyacinth broke loose and travelled downstream, only to re-form in quieter reaches and start the cycle again. In some places the weed became so thick that small boats could not pass, and pumps clogged so often that farmers kept spare parts close by.

A sepia-toned historical photograph capturing three sailboats on a wide river partially covered with floating patches of water hyacinth. On the distant, grassy, rising bank, several tin-roofed, Queenslander-style houses are visible amidst sparse trees under a cloudy sky.

For many living in Brisbane in the 1960s and 70s, water hyacinth was a common feature of the river and remains a vivid memory. Often entire sections of the weed would bloom overnight, turning the river into a “carpet” of green and purple. Many more remember the smell after it was hauled out of the river.

A rare colour image of the infestation from the 1960s shows its enormous scale. Were it not for the havoc it caused across Brisbane, it would have been a rather wondrous sight.

An eye-level shot captures a wide river dense with patches of water hyacinth under a cloudy, light-blue sky. In the foreground, a dark steamboat emitting black smoke from its stack navigates the water, with a smaller white boat nearby. On the left, a rocky cliff is topped with lush green trees and houses. Both banks of the river are lined with houses, trees, and occasional tall buildings, while a distant mountain is visible on the horizon.

An often repeated (but likely apocryphal) story concerns a pair of brothers walking all the way from Bulimba to the Breakfast Creek hotel across the weed carpet. What was true was the dangers of sticking your hand or foot in too deep, with many local creepy crawlies finding the matted weed a particularly fine home.

Various methods of mechanical removal were used on 'The Lilac Devil', but none were truly effective on a large scale. Since 1975, water hyacinth has been kept in check by various control methods including introduced insect species and selective herbicides.

Brisbane vs The Lilac Devil

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