English | Thai


Nymphaea 'Siam Blue Hardy'
The World's First Blue Hardy Waterlily

Hybridized, article and photos by Pairat Songpanich, Thailand
Genetically confirmed by Dr. Vipa Hongtrakul, Thailand
Translated to English by Guntapon Prommoon, Thailand
Edited by Dr. Slearmlarp Wasuwat, Thailand

Click images to enlarge


The cultivation of waterlilies (Nymphaea) has been a passion of water gardening enthusiasts for decades. Experiments with waterlilies have been made successfully resulting in varied shapes, sizes, fragrances and most notably color. The shapes range from cupped and pointed to starry, while colors span the spectrum of red, pink, yellow, white, orange, purple and blue. However, in the more than 100 year history of pollinating hardy waterlilies, the color blue has never been achieved. Various journals and publications have talked about the elusive goal of achieving such a feat. See The Historical Perspective.

N. 'Siam Blue Hardy'

My Goal

From the writings about Bory Latour-Marliac, Andreas Protopapas and Perry Slocum in our Historical Perspective, it can be seen that all three have been great motivators for me to create a "Blue Hardy Waterlily", even though it has been said by some that cross-pollination between the hardy waterlily and tropical waterlily is impossible. I, however, thought there was still hope and that it would be a challenging task to undertake.  

Since 2000, I have received much invaluable advice from Dr. Slearmlarp Wasuwat, member of the International Waterlily & Water Gardening Society (IWGS) Hall of Fame, on hybridization. I started the hybridizing experiment in 2003. Since then I have put a lot of effort into trying to make this dream of a blue hardy come true. 

Dr. Slearmlarp Wasuwat >
Photo by Somkid Chaijitvanit, courtesy of the Bangkok Post


Waterlilies (Family Nymphaeaceae Genus Nymphaea) fall within five subgenera: Anecphya, Brachyceras, Hydrocallis, Lotos and Nymphaea. Only Anecphya and Brachyceras produce blue flowers.

In my quest to produce a blue hardy, the subgenus Nymphaea (hardy) was used as the pod parent and subgenera Anecphya and Brachyceras (tropical) as the pollen parents in the hope of transferring the genes of blue color from the parent to the offspring.

Subgenus Anecphya

Subgenus Brachyceras


Experiments using subgenus Nymphaea with subgenus Anecphya were disappointing. There were no resulting pods or seeds, possibly because the difference in chromosome numbers was too large.

The great achievement was obtained in the cross of Nymphaea with Brachyceras. Few pods were produced and only a few seeds germinated. Among the seedlings to bloom, one hybrid waterlily had purple/blue blossoms!  

N. 'Siam Blue Hardy'

Proving the Hybridity

Morphological differences may be enough to prove heredity in intersubspecific crosses. For intersubgeneric crosses, however, it may not be enough and controversy may arise. Therefore, both morphological marker and molecular marker methods were employed to fulfill the proof.

Morphological Markers Method

Morphological markers that characterize the parents and hybrids were investigated to confirm that this "blue hardy waterlily" was a true hybrid.

Table 1: The Characteristics of the parents and offspring


 Pod Parent *
(Subgenus Nymphaea)

(Blue Hardy Waterlily)

 Pollen Parent *
(Subgenus Brachyceras)







 Surface of the water

 Above the water

 Above the water


















 Plain green

Flecked when young




Growth Habit

 Grows horizontally

 Grows horizontally

 Grows vertically

 * The names of the parents of this hybrid will be disclosed at the appropriate time.

From the characteristics of the parents and offspring presented, it can be seen that offspring possesses genetic germplasm from both pod (Nymphaea) and pollen (Brachyceras) parents. Purple/blue blossom standing high above water are from Brachyceras. The syncarpous carpels, smooth pad edge and horizontal growth are from Nymphaea.

Molecular Markers Method

The use of the molecular marker technique uses DNA as the indicator of the difference on the genetic level of the plant we are studying. The method has much more accuracy than morphological marker method.

The hybrid was genetically confirmed by Dr. Vipa Hongtrakul, Department of Genetics, Faculty of Science, Kasetsart University, Thailand, using PCR-RFLP marker specific to ITS sequence after cutting with three restriction enzymes: AluI, RsaI and MseI (Fig.1). Based on DNA fingerprint, each parent does possess distinct alleles that were found to combine in the hybrid. 

Click to enlarge

New Intersubgeneric Hybrid

The cross-pollination across subgenera (intersubgeneric) is a difficult task to accomplish possibly because the chromosome numbers of the different subgenera are different, but some have managed to pollinate and produce hybrid offspring. See The Nymphaea subgenus Anecphya x subgenus Brachyceras Hybrids in WGI ONLINE Volume 3 Number 1.

N. 'Siam Blue Hardy'
The result of testing this hybrid with both morphological markers and molecular markers methods proves that the hybrid generated has the genetics of both parents and is indeed a new intersubgeneric hybrid between subgenus Nymphaea and subgenus Brachyceras of the genus Nymphaea.  

Why We Call This Blue Hybrid a Blue Hardy Waterlily

Since the hybrid is a result of pollination between a hardy waterlily and a tropical waterlily, its name should refer to both hardy and tropical. However, traits are predominantly those of a hardy waterlily. The blue color of the bloom is only a major trait from a tropical lily. Table 2 will support that it is a blue hardy waterlily!

Table 2: Comparison of the Differences between Hardy and
Tropical Day Blooming Waterlilies
(Adapted from: How Do You Tell The Difference Between Tropical and Hardy Waterlilies? by Kit Knotts


(subgenus Nymphaea)

Tropical Day Bloomers
(subgenus Brachyceras)

Colors include white, all shades of pink, yellow and changeable autumn. Many, though not all, float on the surface of the water and many are cup-shaped with some starry. Colors include white, all shades of pink, yellow, autumn, blue, purple and undertones of green. All stand above the water and shapes are usually starry but some varieties are more cupped.

A characteristic of all hardy waterlily is that the carpels share a single common wall between adjacent carpels. This is called "syncarpous". (Conard, 1905) A characteristic of all tropical day flowering waterlily is that each carpel has its own wall which separates it from the adjacent carpels. This is called "apocarpous". (Conard, 1905)

Hardy pads are rather thick and leathery with smooth edges. Most are plain green though many are lightly mottled with maroon when young. An exception is N. 'Arc-en-ciel' which is green, pink and maroon. Tropical pads are usually somewhat thin with edges slightly scalloped or toothy. They can be plain green, flecked, mottled or whorled with maroon or bronze. 

Growth Habit
Hardies grow horizontally from and along a fleshy rhizomatous rootstock. "Eyes" at points along the rhizome produce new crowns.  Tropicals grow from a single central crown. All leaves and flowers radiate from this point and growth is vertical.

From Table 2 it can be seen that the important characteristics of a hardy waterlily are the syncarpous carpels, smooth edged pads and horizontal growth habit. These three characteristics are the deciding factor in determining that the hybrid is a hardy waterlily and not a tropical day blooming waterlily. In conclusion, the hybrid is a hardy waterlily with a cupped shape, but stands above the water and most importantly has a purple/blue color. So it can be claimed that it is the first Blue Hardy Waterlily in the world.

N. 'Siam Blue Hardy'

Dream Come True

Ever since Joseph Bory Latour-Marliac, the first who succeeded in pollinating hardy waterlilies, there has been the ultimate goal of creating the blue hardy waterlily. Over 100 years had passed and the feat was finally accomplished in 2007 in Thailand, when the first blue hardy in the world was created as envisioned by water garden enthusiasts. To honor the birth place of this hybrid, the name given is Nymphaea 'Siam Blue Hardy'.


The Quest for a Blue Hardy - The Historical Perspective
| Thai
Profile - Pairat Songpanich

WGI ONLINE Journal Table of Contents

Water Gardeners International
Home | Join WGI | Members' Exclusive | Gateway to Water Gardening