Over the summer of 2024, the Royal Botanic Garden Edinburgh welcomed the return of one of the plant world’s most spectacular plants: the giant Victoria water lilies, specifically the ‘Longwood Hybrid.’ This Stories from the Biomes follows the growth and care of the Victoria ‘Longwood Hybrid,’ from germination behind the scenes to its display in the large tropical pond in the Plants and People Glasshouse.
A view of the large pond in the Plants and People Display Glasshouse. (Photo: Kevin Bannon)
Victoria ‘Longwood Hybrid’
A feature of the glasshouse for many years, the giant lily pads have been absent from the Glasshouse Pond due to the closure of the Glasshouses for the Edinburgh Biomes Project. Within the Nymphaeaceae family of plants, the Victoria genus comprises three species, with this specific hybrid being a cross of V. amazonica, native to the Amazon River basin, and V. cruziana, found in the Paraná-Paraguay River systems. The ‘Longwood Hybrid’ gets its name from Longwood Gardens, where it was first created by Patrick Nutt in 1960. Although the Glasshouses at RBGE remain closed to the public, new seeds were sown for the sake of horticulture training, and for the enjoyment of staff and students.
Germination and Growth
Arriving in December 2023 from Longwood Gardens near Philadelphia, the small seeds are safely packed in containers filled with distilled water. (Photo: Kevin Bannon)
Some of the pea-sized seeds are decanted for sorting and inspection. (Photo: Kevin Bannon)
When working with aquatics, weight is key to keeping everything submerged. Small clay pots are prepared with a heavy loam medium and a small amount of gravel as a top dressing. With a seed each sown inside, the small pots are placed into the propagation pond in the tropical propagation glasshouse.
In January, the first cotyledons emerge roughly 10 days after being sown, with junior leaves following in rapid succession. With large grow lights overhead, the pond’s water temperature is maintained at 27 degrees while a pump keeps the water circulating and filtered. (Photo: Kevin Bannon)
Moving to Display
After four months, the plants are moved from the smaller propagation pond to the large pond in the Plants and People Tropical Glasshouse. Two 290-litre planting pots are prepared with a loam medium and covered with a layer of gravel on the surface similar to the smaller propagation pots used for germination. These pots are slowly sunk into the pond and allowed to warm up a week prior to the move. Although extremely heavy, the pots become easier to move once submerged in the warm water.
Left: In early April, the more robust plants await potting into their final display pots. Right: One of the two planting pots before it is sunk into the pond. The plastic retaining pot in the middle will later be removed to allow the root ball to settle in. (Photo: Kevin Bannon)
RBGE apprentices Ryan Vince and Patricia Berakova lower the young plants into the warm water. They are later repositioned to different sides of the pond after they establish and begin to expand. (Photo: Kevin Bannon)
Care and Maintenance
Glasshouse horticulturists Pat Clifford and Kate Miller use a fork to remove old and brittle leaves, taking care to avoid the needle-like spines underneath. (Photo: Kevin Bannon)
Over the summer, the oldest and largest pads are regularly removed to prevent overcrowding and enable newer leaves to grow. A feed is applied in the form of “fertiliser balls,” which are prepared during the germination stage. Roughly 100–150 of these fertiliser balls, a compact mixture of granular feed and heavy medium, are handmade and left to dry until hardened.
At roughly the size of a tennis ball (but not as visually pretty), three of these nutrient-packed balls are pushed into each of the large pots weekly, slowly breaking down once lodged in between the Victoria’s wet roots. (Photo: Kevin Bannon)
Older leaves, with damage from raindrops from the leaking Glasshouse roof are removed regularly. Additional aquatic plants such as Pontederia crassipes (water hyacinth), Nelumbo nucifera, and Pistia stratiotes float nearby. (Photo: Kevin Bannon)
Glasshouse horticulturist Pat Clifford demonstrates the technique of carrying the removed leaves out of the water to avoid damaging the other leaves and small plants in the pond. [Photo: Kevin Bannon]
A Closer Look – Flower, Pollination, and Defence
The night-blooming flowers open white on the first night and turn dark pink on the second night. (Photo: Kevin Bannon)
In the wild, V. amazonica relies on scarab beetles for pollination. At night, the bright white flower emits a strong scent, attracting the beetles. Once inside, the flower closes, trapping the beetles until the following evening. During this time, the petals turn dark pink due to the release of anthocyanins, signalling an end to its flowering and that pollination has occurred. The beetles leave, covered in pollen, to find another attractive flower.
The large, white flower on show early in the morning, with a new leaf and flower buds emerging nearby. (Photo: Kevin Bannon)
At RBGE, the Victorias are treated as annuals, and no seeds are collected to ensure the growth of true hybrids from new seeds harvested at Longwood Gardens each year. Whether pollinated or not, the colour changing process comes to an end with the flower now a dark pink resting in the water. (Photo: Kevin Bannon)
Strength and Buoyancy
Another defining feature of the plant morphology is the high lip that surrounds the edge of each leaf. This helps keep the leaf afloat and acts like a bumper, making the leaf strong enough to push against other aquatic plants competing for the valuable exposure to sunlight. (Photo: Kevin Bannon)
The hollow pockets within the petiole assist in the overall buoyancy while connecting the leaf to the main plant, and like almost everything else are covered with glove piercing spines. (Photo: Kevin Bannon)
The raised ribs and sharp spines on the underside of the leaf facilitates buoyancy, supporting the wide spreading leaves. (Photo: Kevin Bannon)
From deep purples to varying shades of green and red, a web like pattern hides under each leave, supporting its weight spread over the water’s surface. (Photo: Kevin Bannon)
Since the Victorian era, the massive leaves have drawn attention for their ability to support the weight of a small child. Recently, a competition initiated by Denver Botanic Gardens, with ten other botanic gardens participating, tested the strength of the giant water lilies. Watch below to see RBGE’s entry hold an impressive 48 kg! (105.8 pounds).
💚🏴 Are you ready for the #WaterlilyWeighOff24? It’s time for Scotland to weigh in on the action! With a Scottish twist up our sleeves (we’re looking at you @IRN-BRU 👀), a little help from our Herbarium presses, and a very special guest appearance from Marley, the Botanics cat, we were more than ready to take on the challenge with our Victoria ‘Longwood Hybrid’ waterlilies. 💪 Royal Botanic Garden Edinburgh officially weighs in at 48kg/ 105.8lbs! Thanks to @Denver Botanic Gardens for challenging us! #RoyalBotanicGardenEdinburgh#TheBotanics#Waterlilies
In November, the leaves become smaller and their raised edges lower. The Victorias’ growth slows due to reduced light levels, and feeding is stopped. (Photo: Kevin Bannon)
Glasshouse horticulturist Pat Clifford uses a fork to remove the large root ball. Soon after, the pots are removed and cleaned for the next growing season. (Photo: Kevin Bannon)
A colourful reminder from above during the warm summer months (Photo: Kevin Bannon)
In cultivation the Victoria genus of plants in the Glasshouses are a symbol of innovation in horticulture, and still to this day represents both a challenging and rewarding journey from seed to display. There’s no doubt that this amazing plant will continue to be a focal point in the Glasshouses. Their beauty and grandeur on show are a direct result of the skill and care from the Glasshouse horticulturists, who, before any public displays, work in the background to bring the different parts of the plant world to life within the Glasshouses.
Tending to the Victorias (Illustration: Kevin Bannon)
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