On 14 February, people across the world will be presenting those they care about with gifts. In some countries these gifts are given to a partner or spouse, while in others they are used to share love with friends and family.

Here in the UK, these gifts are typified by roses, chocolates and champagne – or, as we plant scientists might call them, Rosa, Theobroma cacao, and Vitis vinifera.

Since plants and Valentine’s Day share this link, I thought I’d do a bit of searching and find out more about the species behind our favourite gifts – and for each, I’ve given my own alternative suggestion to our traditions.

Bacterial love

Even our bacteria can share the love. Photo: Izzy Webb.

Saint Valentine

Most people think of Saint Valentine as an imprisoned martyr. But in Slovenia, Saint Valentine was more than this. He is one of the saints of spring, and also the patron saint of beekeepers. Slovenian tradition is that Valentine brings “the key to the roots” – meaning that winter is over, spring is coming, and nature is ready to awaken.

Saint Valentine baptising Saint Lucilla.

Saint Valentine baptising Saint Lucilla by the Italian painter Jacopo Bassano.

Far before it was celebrated as a day of love, Valentine’s Day was celebrated as the first day back in the fields. Coincidentally, I will actually be harvesting some plants that day – an unplanned surprise I discovered once I began writing this post.

My suggestionditch the romantic dinner, get out into the garden and grab a spade.


You might not  realise that a dozen red roses are, in fact, twelve selectively chosen mutants. Flower development relies on the plant’s ability to differentiate into petals, sepals, stamens and carpels (time to remember your GCSE Biology here). The stamens and carpels are the reproductive organs, the sepals protective, and the petals there to attract pollinators.

Most ornamental roses have been selectively bred over thousands of years to be ‘double-flowered’, where many or all of their stamens have mutated into petal forms. Selective breeding is also what has led to the huge variation in colour and shape in the different rose varieties we see in the shops.

Variation in rose flower colour

Two roses (Rosa species). Roses are bred for several different characteristics, including flower colour. Photo: Izzy Webb.

Roses and other flowers are in high demand over Valentine’s Day across the world. In the UK alone, the fresh cut flower and indoor plant market is worth £2.2billion. To give this some context, the UK music industry is worth around £2billion. This equates to each person spending £36 a year on plants!

A large proportion of cut flowers are now imported to the UK – meaning that your Valentine’s bouquet is damaging your carbon footprint (and possibly your ethical one too – flowers imported from abroad may be grown by people on a very low wage). There is also growing concern that flowers, like our food crops, are being grown with pesticides – and not many places sell organic flowers.

My suggestion: rather than splashing out on potentially unethical and probably expensive roses, go for a walk and pick some seasonal wildflowers (or even plant some earlier in the year to provide your own home-grown bouquet. This might need to be a plan for 2016). Alternatively, use origami for that homemade touch.


Chocolate comes from the cacao tree, Theobroma cacao. The name Theobroma comes from Greek, meaning “food of the gods”. It is part of the Malvaceae family – a very useful family indeed. As well as cacao, the family includes cotton, hibiscus, okra and balsawood.

Cacao pods on a tree

Cacao pods in the Palm House at the Royal Botanic Gardens, Kew. Photo: Kew Gardens/Flickr.

The cacao tree is native to the deep tropical regions of Central and South America, and it’s the seed of the tree – the cocoa bean – that we use to make our favourite sugary snack. We use a lot of these seeds too – in 2008-2009 the world produced over 3,515,000 tonnes of cocoa!

Chocolate is renowned for being high in sugar and fats. But there’s some good stuff in there too. Cocoa beans contain up to 10% phenols and flavonoids – antioxidants that potentially inhibit cancer or cardiovascular diseases. They also contain caffeine, an essential part of any PhD student’s diet.

Like many of our native crops, cocoa comes under threat by pests and diseases. Added to this, climate change will endanger current habitats.

The genetic diversity of cocoa is held in the fields where it is grown. Whereas we can keep seedbank collections of many plants, cocoa seeds cannot handle these storage conditions – so we rely completely on the trees in the ground.

Cacao pods

A closeup of cacao pods. Photo: outdoorPDK/Flickr.

Just as we are working on improving staple crops such as wheat or barley to handle these threats, we will need to do the same for cocoa if we are to save our chocolate!

My suggestion: take your loved ones to a botanical garden and show them what a cocoa plant really looks like. Then you should probably eat some chocolate – in case you missed this morning’s fourth coffee.


Champagne, like other wines, is produced from fermented grapes (Vitis vinefera). Only a few varieties of grape are permitted, and there is a comprehensive set of rules set down for what may be grown and where.

It isn’t the grapes, however, that plays the main role in the production of champagne. This role is left to something much smaller, and often overlooked: yeast.

Pouring champagne

Champagne’s distinct flavour and properties are due, not only to the grape variety, but also the yeast used for fermentation. Photo: Svante Adermark/Flickr.

Whereas most wines undergo one fermentation, Champagne and other sparkling wines undergo two fermentations. The skins of grapes are home to yeasts, and these, if provided with sugars, will convert the juice into ethanol (alcohol) and carbon dioxide. Bottling the wine before fermentation is complete will lead to bubbles of carbon dioxide being produced – and in very early champagne production (before better glass was developed), this meant bottles often exploded.

Once the first fermentation is complete, the second occurs in the bottle. Several grammes of yeast (Saccharomyces cereviciae) is added to the bottle, along with rock sugar. Individual houses have their own unique recipe for this second step. The yeast provides unique flavour to the champagne, and it’s thought to take over a year and a half to reach its full taste.

Evening in the Champagne region

Vines growing in Champagne, France. Photo: Vincent Brassinne/Flickr

Of course, Saccharaomyces cereviciae isn’t only known for alcohol fermentation. Anyone who’s ever made their own bread will recognise that species name. Of course, it’s a different strain of this yeast used in breadmaking – handily differentiated by the names “baker’s yeast” and “brewer’s yeast”.

My suggestion: Since you probably don’t own any land in the Champagne region (or a vineyard anywhere for that matter), show some Valentine’s love to yeast by baking a nice loaf of bread.

And finally, for the protein biochemists …


As a sixth form biologist, I was tasked with making a ‘valine-tines’ card as a classroom activity. As silly as it sounds, it stuck with my classmates and me – two of my friends still jokingly describe each other as their “val”.

Valine and valerian

Valine’s molecular structure and valerian growing in London. Photo: [Duncan]/Flickr.

Valine is one of the twenty amino acids that make up our proteins. Importantly for this blog, it is named after a plant – valerian. Valerian is a medicinal herb first described by Hippocrates, and its name comes from the Latin for ‘strong and healthy’. Interestingly, valerian root and leaves are cat attractants, and are as safe as catnip.

My suggestion: Any singleton out there who has accepted their inevitable life as a crazy cat lady … grab some valerian and start your cat collection now.

Izzy is a John Innes Centre PhD student. She tweets as @isabelwebb.

Featured image: Flower Macro Shot by Olivier Blitzblum/Flickr.


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