Giant Waterlilies: Leaves Dressed to Impress

Standard

Victoria cruziana. Photo: Mercy from Wikimedia Commons

I’ve just come back from the freshly renovated water garden at the Montreal Botanical Garden which now features a new central pond containing all three species of giant waterlily, also called water platters—Victoria amazonicaV. cruziana and V. ‘Longwood Hybrid’—and who can help but be impressed by the huge size of the leaves: up to 3 meters (9.8 ft) in diameter! 

The plants are aquatic, of course, found still waters and bayous of the Amazon basin in the case of V. amazonica and in the Parana-Paraguay basin, also in South America, in the case of V. cruziana. As for V. ‘Longwood Hybrid’, it results from a cross between the two and was, as the name suggests, developed at Longwood Gardens in Pennsylvania … where I saw it in bloom two weeks earlier (yes, I get around!)

The genus was named Victoria in 1837 for the recently crowned Queen Victoria and has become a mainstay in botanical gardens around the world. Often giant waterlilies are grown in a greenhouse, as they need tropical conditions. However, they also can also be grown outdoors in heated ponds, the case both in Montreal and Longwood Gardens.

It’s hard to believe that these giant plants are annuals, but that’s how they’re usually grown in botanical gardens, with new ones started each winter from seed. 

Designed to Float

The underside of the leaf shows an intricate pattern of ribs. Photo: http://www.reddit.com

The leaves float on the water thanks to surface tension and thick air-filled ribs on the undersides with an intricate highly geometric shape.

Yes, you can place a small child on the leaf and it will hold it. Photo: http://www.montrealgazette.com

The actual leaf blade is paper thin and easily torn, but can nonetheless support the weight of a child … if it is carefully placed on the leaf. (I suggest trying this with some other child than your own.)

The leaves are turned up at the edges to keep water from washing in. However, when that does happen (say due to a splashing animal or rain), there are tiny holes, barely visible, designed to let excess water drain out, keeping the top of the leaf clean and dry.

Thorny Foliage

The thorny edge of Victoria cruziana. Photo: bergenwatergardens.com

You can’t help but notice that the sides of the leaves are covered in thorns and if you flipped the leaf over you’d see the bottom of the leaf is likewise dotted with the same nasty prickles. You’d assume that these thorns are designed to protect them from fish or aquatic mammals, but you’d be wrong. According to the docent at Longwood Gardens, the purpose of the thorns is to tear apart competing aquatic plants, shearing them off neatly as the leaf moves in the water, thus reducing competition. 

Strange but Beautiful Flowers

The first-night bloom of Victoria amazonica. It will be pink the following night. Photo: Bilby, Wikimedia Commons

I was really lucky to see flowers in both gardens this year. The huge floating flowers are up to 40 cm (15 inches) in diameter and each plant usually produces only a few per year. Since each individual flower lasts only two days, you have to be there at just the right time! 

Pink petals mean the flower (Victoria amazonica) is now male and scentless. Photo: worldoffloweringplants.com

The life cycle of the flower is fascinating. Each bloom opens in the evening as a giant white flower. It is, at this point, female, with a fertile stigma. The first-night flower gives off an intense perfume rather like pineapple, actually producing heat up to 10˚C warmer than the surrounding air to better diffuse the odor. This attracts tiny scarab beetles (Cyclocephala spp.) that arrive in droves to feed inside on staminodes inside the flower … and also mate. The flower closes during the day, trapping the scarabs inside, but it’s not such a bad prison, as they have plenty to eat and are protected from their enemies. The next evening, the flower opens again, but is now pink to reddish in color and scentless. And it’s become male, with fertile stamens that coat the beetles with pollen as they fly away (they’re not interested in the second-night flower, the staminoids they feed on having dried up by then) … to land directly on the intensely perfumed female flower of another plant and repeat the process. This guarantees cross-pollination. 

Where giant water lilies are grown outside South America, the type of scarab necessary for pollination is not available, so the flowers have to be pollinated by hand.

The Water Lily War

The discovery of the Amazonian giant waterlily (V. amazonica, originally called Victoria regia) by Sir Richard Schomburgk in 1937 caused a frenzy among botanical gardens of the world. Each strove to be the first to grow this exotic plant, but they failed repeatedly. 

Victoria amazonica flower opening. Ill.: Walter Hood Fitch, Kew Gardens

Eventually, in 1849, seeds sent to Kew Gardens (near London, England), carefully stored in wet clay, germinated, but remained small and failed to bloom. However, Joseph Paxton, head gardener for the sixth Duke of Devonshire at Chatsworth House, considered one of the finest gardens of its day, had recently built a “great conservatory,” a tropical greenhouse to which he added a large specially heated tank. He managed to obtain a young plant from Kew and it positively thrived under his ministrations, with leaves growing to near-record size. 

On November 2, 1849. Queen Victoria herself came to Chatsworth see the opening of the first flower ever to bloom outside of South America, to the sound of an orchestra playing God Save the Queen. 

The illustration of Paxton’s daughter standing on a giant waterlily leaf at Chatsworth caused a media sensation. Ill.: lliustrated London News

The Duke famously placed Paxton’s daughter on a leaf and the resulting drawing appeared in the Illustrated London News on November 14, 1849, causing a media sensation. Botanical gardens and estate gardens around the world began installing waterlily greenhouses with heated ponds and growing giant waterlilies themselves. In fact, giant waterlilies remain stars to this day and you can be sure they regularly appear in media reports around the world.


Giant waterlilies: not something you’ll likely want to grow in your own garden, but certainly a plant you’ll want to take notice of when you visit the great botanical gardens of the world.

Advertisements

Water Lily, Pond-Lily or Lotus?

Standard

Gardeners confuse the three plants above, but they are really very different! Source: http://www.woodvalefishandlilyfarm.com.au & http://www.rarexoticseeds.com

There’s considerable confusion surrounding the common names of aquatic plants in the three genera Nymphaea, Nuphar and Nelumbo. True enough, they all have fairly circular leaves that float on fresh water at least part of the year and grow with their tuberous roots in the mud of a pond or lake (or in a pot!), but they’re not necessarily even closely related. Neophytes often simply call them water lilies, but serious gardeners need to know the difference.

Water Lily

20181023C Nymphaea 'Marliacea Carnea' www.crocus.co.uk

Nymphaea ‘Marliacea Carnea’, with its abundant yellow stamens, is clearly a water lily, not a pond-lily or a lotus. Source: http://www.crocus.co.uk

Water lily or waterlily (both are correct) is the preferred name for plants of the genus Nymphaea of the Nymphaeaceae family.

Water lily flowers have numerous petals: at least eight and usually many more. They can be white, pink, red, blue or pale yellow, but never golden yellow (that color is limited to pond-lilies, that is, plants of the genus Nuphar). The center of the flower is usually packed with abundant yellow stamens.

The flowers either float on the water’s surface or are carried on a short stem above the water. This depends on the species. Note too that with water lilies, the seed capsules sink below the water surface, out of sight, when the flower finishes blooming.

20181023F Nymphaea alba davisla.wordpress.com.jpg

Leaves of the European white water lily (Nymphaea alba). Source: davisla.wordpress.com

The more or less circular leaves have a slit on one side that allows rain water to drain off, and the leaf stalk is attached at the base of the slit. This feature is shared with pond-lilies (Nuphar spp.).

Water lilies are extremely ornamental plants and very popular in water gardens. There are hundreds of hybrids, both tropical and hardy. Some are day bloomers, others are night bloomers.

20181023D boktowergardens.org.jpg

Giant water lily (Victoria sp.). Source: boktowergardens.org

Water lily is also the name used with a few other plants in the Nymphaeaceae family with similar growth habits, such as the giant water lily (Victoria spp.).

Pond-Lily

20181023E Nuphar pumila, KENPEI, Wikimedia Commons.jpg

Small pond-lily (Nuphar pumila). Source: KENPEI, Wikimedia Commons

No one seems to agree on what to call plants in the genus Nuphar. They go by such names as water lily (which should automatically be banned to avoid confusion with the genus Nymphaea just described), bonnet lily and spatterdock among others. I recommend pond-lily, largely because it is widely understood on both sides of the Atlantic and has been used for centuries.

Like the water lily, the pond lily a member of the Nymphaeceae family and indeed, the leaves of the two are pretty much undistinguishable, with the same circular shape and drainage slit. However, the flowers are very different. They are golden yellow, a color absent from the water lily palette, and are made up not of numerous petals, but of only 4 to 6 sepals forming a cup. (There are petals, but they’re insignificant.) Also, when the jug-shaped fruit forms, it floats on the surface of the water and therefore remains visible.

The pond-lily is generally considered less attractive than the water lily and is rarely grown in water gardens.

Lotus

20181023G Nelumbo 'Mrs. Perry D. Slocum' www.woodvalefishandlilyfarm.com.au.jpg

Lotus (Nelumbo ‘Mrs. Perry D. Slocum’). Note the cone-shaped receptacle in the center. Source: http://www.woodvalefishandlilyfarm.com.au

In the strictest sense, the term lotus applies only to plants of the genus Nelumbo, consisting of just two species (Nelumbo nucifera and N. lutea) and their hybrids. Curiously, lotuses do not belong to the Nymphaeaceae family, but rather to their own family, the Nelumbonaceae. In fact, they are not even very close relatives of Nymphaeaceae, but are rather more closely related to plane trees (Platanus spp.) and proteas (Proteaceae), both woody terrestrial plants. If the two families appear similar, it’s because of convergent evolution, both having adopted similar strategies to survive in an aquatic environment.

20181023H Arulonline pixabay.com.jpg

Lotus leaves repel water. Source: Arulonline pixabay.com.

The lotus leaf is peltate, with the leaf stalk attached to the center, underneath the leaf, rather than the edge. There is no slot to allow rain to drain away. Instead, the leaf is hydrophobic and raindrops bead up on its surface and roll around, eventually being pushed off the leaf by the wind. Only the first leaves of the season float. As the summer advances, the others begin to appear on straight, upright stems sometimes rising more than 5 feet (150 cm) in height above the water.

Lotus flowers are often huge—up to 12 inches (30 cm) in diameter—and are borne above the water on strong stems. Composed of a variable but usually fairly large number of tepals (petals and sepals), they do look superficially like a water lily flower, but can be instantly distinguished by the large cone-shaped floral receptacle in the center of the flower.

20181023I Vmenkov, Wikimedia Commons.JPG

The Lotus flower’s cone-shaped floral receptacle makes it easy to tell from water lily flowers. Source: Vmenkov, Wikimedia Commons

When the tepals drop off (they only last a day), the receptacle remains upright, at first green, then brown. It eventually opens to release large hard round seeds. Dried, the receptacle often serves as a floral decoration. When you see these cone-shaped seed capsules with their numerous holes, you know you’re definitely dealing with a lotus.

By now, it should be clear that the lotus (Nelumbo) and the water lily (Nymphaea) are two vastly different, unrelated plants, but … two species of Nymphaea have long been called lotuses, the Egyptian white lotus (Nymphaea lotus) and the blue lotus or blue Egyptian lotus (N. caerulea). Ideally, we should call them, respectively, the Egyptian white water lily and the Egyptian blue water lily … but old names tend to cling to plants for a long time and I don’t think that is going to happen any time soon!

As a result, I find I have to call the two Nelumbo species sacred lotus (Nelumbo nucifera) and American lotus (N. lutea) if I want to make myself perfectly clear. Annoying, isn’t it?

The Botanical Name Lotus

20181023J Lotus corniculatus, Wilson44691, Wikimedia Commons.jpg

A trefoil (here, the bird’s-foot trefoil, Lotus corniculatus) is certainly nothing like a water lily nor a lotus and there is little risk of confusion. Source: Wilson44691, Wikimedia Commons

To further confuse the situation, Linnaeus (1707–1778) gave the botanical name Lotus to a genus in the Fabaceae family (legumes) consisting of about 100 terrestrial plants with pea flower-shaped blooms. Simply call them trefoils and remember they have no connection whatsoever with Nymphaea, Nuphar or Nelumbo and therefore, there should be no risk of confusion.

The Right Name on the Right Plant

As gardeners, we should always know the right names for our plants, otherwise the gardening world will become be nothing but a huge tower of Babel!