Amazonian adventures at Wisley

The latest addition to Wisley's plant collection is one of the world's biggest waterlilies

It started with a seed smaller than my little fingernail, and though you would scarcely believe, it was a seed full of aspirations of being big. The plant it would eventually become is known in its native land as Yrupe, a lovely self-descriptive name meaning water platter. More commonly over here it is known as the giant waterlily and was a new addition to the aquatic collection at the Wisley glasshouse this summer. Yrupe is known botanically as Victoria and there are two species in the genus: V. amazonica and V. cruziana. Here at Wisley we are growing a cross between the two known as Victoria ‘Longwood Hybrid’ named after the gardens where it was bred.

Being the first year of growing we have had a variety of setbacks, beginning with a later than hoped for start. I received the seeds in March, nearly a month behind our anticipated sowing date. So without further delay I hastened to sow our seed.

Photograph by Rohanna HeyesNew word for the day: operculum, here the operculum is gently but firmly being prised from the micropyle, care needs to be taken not to damage the seed's embryo. Victoria seeds can be tricky to get successful germination some recommend removing the operculum, this process is referred to as 'nicking'.

Photograph: Rohanna Heyes Success! The operculum is removed and the delicate embryo beneath is still intact.

I tried a few different sowing methods, half the seed we had was nicked and surface sown into loam which was topped with grit to keep in place (see below). The other half of the nicked seed was ‘sown’ into bags of water. These steps were repeated with the remaining un-nicked seed. All seed was then kept submerged in a water tray in a propagation box, with bottom heat which kept the water temperature above 26oC. As expected I found that our nicked seed had higher germination. However one splendid specimen did develop from an un-nicked seed sown directly into loam, incidentally this specimen also went on to produce the first flower.

Photo: Rohanna Heyes Grit helps to keep the seed in place, but doesn’t actually cover the seed itself. Here the tiniest first leaf emerges from an un-nicked seed, sown directly into loam.

 From tiny beginnings: the un-nicked seed grew strongly and flowered well for me in the snug climate of my service house, as did two other nicked seed specimens. Here I am pictured with the first flower, a warmth from the flower itself could be detected on the nose when smelling the flower at close range and the whole service house smelt like pineapple soap.

Photo: Peter JonesI felt so pleased with the growth of the plants, and though we had started late I felt a degree of success in getting the plants to flower. However it's not all waterlily flowers smelling of pineapples. When we put the plants outside, in our specially designed heated tank, we found they never thrived quite as well as they did in the service house. A variety of factors have probably contributed to this, first of all we had some cooler night temperatures. Then just as summer was getting into full swing along came plague of aphids, by the time we worked out how best to treat them we floundered again with the recent autumnal night temperatures.

Photo: Rohanna HeyesAphids were everywhere, even on the undersides of the leaf where it rises out of the water. Here you can also see the sharp spines which coat the undersides of the leaves and the petioles, a sure defence against herbivory.

I definitely will be making some detailed notes for growing the waterlilies next year and hopefully we can get even better results, especially outside.

Meanwhile fingers crossed it isn’t completely autumn, we get a lovely Indian summer, and one or two of those flower buds make an appearance. If you're interested in learning more about waterlilies I found the website of Kit and Ben Knotts really interesting, you might even be inspired to try at home! Our Victoria waterlily pond can be found at the back of the glasshouse, access via the exit doors in the arid section.

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