A Travelling Botanist: A plant worth its weight in gold!

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Guest blog series by: Sophie Mogg

To those of you who cook exquisite dishes using saffron, I am sure you are aware of its beautiful aroma and colour as well as its hefty price tag. The question I want to ask is, can you name the plant saffron is derived from?

Crocus sativus
Crocus sativus

Saffron is the most expensive spice in the world and is harvested from Crocus sativus, commonly referred to as the saffron crocus. C. sativus will grow to approximately 20-30cm and produce up to four flowers, the saffron itself being the stigmata of the plant and often referred to as strands. This domesticated crocus is in fact sterile and so bulbs must be divided and replanted in order for more crocuses to grow. This plant is sterile due to it’s triploid genome, meaning that it has three paired sets of chromosomes.

Saffron, like tea, is hand-harvested with each flower only yielding 3 strands. The flowers bloom at dawn, gradually withering throughout the day and the stigmata rapidly losing their aroma and colour hence the flowers must be collected quickly so that the saffron can be removed from the flower and dried. It is estimated that over 85,000 flowers would be required to produce 1 kg of saffron. These factors are what contribute to the high sale price of saffron. In order to keep your saffron fresh, buy it in small quantities and store it in an airtight container away from sunlight. This will ensure it stays in top condition for 3-6 months.

The use of saffron is not limited to South Asia and is often used to impart a pale orange-yellow hue to foods such as rice but it also features in Swedish baked goods, soups and Italian liqueurs such as Strega and Fernet. Kashmiri saffron, produced in Pakistan, is commercially sold for use as both a dye and a folk remedy for melancholy. Saffron has also had notable references made to it in the treatment of scarlet fever, measles, Alzheimer’s disease and is currently being investigated for its potential to treat to asthma and insomnia. If you’re interested in the research conducted into the use of saffron you can find all the relevant links here.

Please complete the poll to have a say in the type of plant that features in the series. If you choose other, please specify what you would like to see.

For more information:

Grow your own saffron crocus 

Interesting facts about Crocus sativus

BBC Recipes using Saffron

Did you know you can request a guest blog on a plant of your choice? Comment below with your favourite plant and if it’s in our collection and found within South Asia or Europe, I’ll be happy to feature it!

Saffron: the world’s most expensive spice (Part 2)

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by Jemma

This two-part blog post has looked at Crocus sativus, also known as saffron. Part 1 focused on the plant’s history in Europe ( Part 2 will now focus on its genetics, harvest and uses.



Saffron is a species of autumn-flowering plant that can grow up to 20-30 cm and produces around 4 flowers. These light- to dark-purple flowers each possess 3 bright crimson stigmas from which the spice saffron is obtained.

Saffron flowers.  Image taken from
Saffron flowers.
Image taken from


Crocus sativus is a monomorphic clone, which means that almost every saffron plant is identical both physically and genetically. It is unknown in the wild and probably descends from Crocus cartwrightianus (also known as ‘wild saffron’), though Crocus thomasii and Crocus pallasii have also been suggested as saffron precursors. The species sativus probably arose through extensive selective breeding by growers after longer stigmas during Bronze Age Crete.

Crocus cartwrightianus - the plant from which the saffron crocus might be descended  Image taken from:
Crocus cartwrightianus – the plant from which the saffron crocus might be descended
Image taken from:

The saffron crocus is a triploid (possess 3 sets of each chromosome) that is male sterile and incapable of reproduction. Thus, the majority of propagation of Crocus sativus takes place by asexual reproduction.



As mentioned previously, the plants crimson stigmas are the source of the popular spice. Due to the few produced per plant and the difficulty involved in manually extracting the minute stigmas, the saffron spice is the world’s most expensive spice by weight. Large quantities of flowers are required in order for marketable amount of saffron to be produced. Approximately 75,000 flowers, which give around 225,000 stigmas, are required to obtain a single pound (0.5 kg) of the spice. Each of these stigmas must be collected by hand and then immediately dried to prevent decomposition or mould from damaging them.


Medicinal uses

For as long as it has been cultivated by Homo sapiens, the saffron crocus has been used extensively for medicinal purposes. Even the paintwork by the Minoans hinted at the possibility of its use as a drug. Ancient Egyptian healers used Crocus sativus to treat a wide range of gastrointestinal problems; from stomach ache to internal bleeding. They also viewed it as an aphrodisiac, poison antidote and cure for measles. Alexander the Great was noted for having baths with saffron to help heal wounds after a battle. With its medieval revival, the medicinal uses of the crocus increased further. It was used to treat everything from coughs to smallpox, insomnia to heart diseases, and from stomach ache to gout. Saffron was even believed to be able to cure the Black Death.

Materia Medica jar containing saffron.
Materia Medica jar containing saffron.

Today, saffron is still used frequently in both alternative and modern medicine. Crocus sativus is included in the hematoxylin-phloxine-saffron (HPS) stain and Movat’s pentachrome stain, both of which are tissue stains used to make structures more visible under a microscope. This is because saffron stains collagen (most abundant protein and the main structural protein) yellow.

A tissue sample stained with HPS stain. Collagen is dyed yellow whilst muscle and cytoplasm are both pink. Image taken from
A tissue sample stained with HPS stain. Collagen is dyed yellow whilst muscle and cytoplasm are both pink. Image taken from

Use as a dye

For millennia saffron has been used to colour textiles and other items. It was traditionally reserved for nobles, political elites and important religious figures to emphasise their social standing. Even in small amounts, the sativus stamens produced a bright yellow-orange dye but with increasing amounts of saffron used, a richer shade of red was achieved. This led to these richer shades indicating those who were of particular importance. However, saffron is an unstable colouring agent over long periods of time, resulting in the vibrant colours to fade quickly. Over time there have been numerous attempts to replace saffron with a cheaper dye. Crocin, the main chemical in saffron that imparts the colour, has been discovered in other plants and is now extracted cheaper and easier from species in the Gardenia genus.


Culinary uses

Another use for saffron that dates back thousands of years is for cooking. A popular addition worldwide, saffron imparts a bright yellow-orange hue onto dishes and is included in everything from curies and soups to cheeses and baked goods. It is also sometimes added to liquors for flavour and colour. However, due to its high price, saffron is often substituted or combined with other spices in order to reduce the cost. Safflower (Carthamus tinctorius) and turmeric (Curcuma longa) are the most common replacements as they mimic the colour imparted by saffron. Though they can produce a similar colour to the pricey Crocus sativus spice neither safflower nor turmeric can replicate its distinctive taste (which is mainly due to the compound picrocrocin).

Safflower is sometimes used as a cheaper alternative to saffron
Safflower is sometimes used as a cheaper alternative to saffron

Other uses

In addition to the uses mentioned already, saffron was also a popular ingredient in perfumes in ancient Greece and Rome. They also included Crocus sativus in cosmetics, wine and potpourri. It was even considered a worthy offering for the gods. Queen Cleopatra of Egypt added saffron to her bathwater as she considered it an aphrodisiac.

Saffron: The world’s most expensive spice (part 1)

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by Jemma


This two-part blog post is going to focus on Crocus sativus, also known as saffron. Part 1 is going to focus on the plant’s history in Europe and part 2 ( will focus on its genetics, harvest and uses.


Ancient Times

The cultivation and trade of the saffron crocus by humans has persisted for around 4 millennia; spanning cultures, continents and civilisations. The first recorded image of saffron appears in Minoan paintings. Though there is no written record of what they used the crocus for, suggestions have been made (mentioned in part 2) and it is clear that the plant held some significance for them. A powerful earthquake followed by a volcanic eruption resulted in the loss of this early settlement around 1,500 BCE. The Minoan herbal paintings survived over the next few millennia through being entombed by the volcanic ash, which preserved these early frescoes.

Minoan fresco depicting a saffron gatherer.  Image taken from:
Minoan fresco depicting a saffron gatherer.
Image taken from:

Saffron again became popular during the time of the ancient Greeks, when early documentation shows that they cultivated and harvested the plant for its spice. During this time, saffron began to be widely traded across the Mediterranean. The plant even had its own origin legend: the story of Crocus and Smilax. Crocus, a handsome young man, falls for the nymph (a female nature deity) Smilax. At first Smilax is flattered but she soon tires of his advances and turns Crocus into a saffron plant; the bright stigmas of the flower representing the glow of the undying and unrequited passion of Crocus. Possibly for this reason, saffron was widely associated with the class of professional courtesans and entertainers called the hetaerae. Though it remained a popular spice and medicine for many centuries, Crocus sativus cultivation in Europe went into decline following the fall of the Roman Empire.


It should be noted, however, that Crocus sativus cultivation was not limited to Europe. Whilst its popularity was still spreading, saffron began to be grown further and further from Greece. By the 3rd century AD, it had spread to China and was incorporated into their traditional medicinal practices.


Medieval Revival

For several centuries the cultivation of Crocus sativus was, for the most part, none-existent throughout Europe. This changed after the Moorish civilisation spread from North Africa around the 8th century and began reintroducing the spice. Saffron was rare, expensive and in high demand right up until the 14th century, when its use soared due to the medicinal applications of the plant in attempted treatments for the Black Death. However, many of the farmers that grew Crocus sativus had died from the disease and the demand far outstripped the supply. Thus large quantities of non-European saffron began to be heavily imported. The trade of saffron became of such significance that those found guilty of adulterating supplies were fined, imprisoned and even executed.

An image from La Francescina manuscript (1474) showing Black Death victims being treated. Image taken from
An image from La Francescina manuscript (1474) showing Black Death victims being treated. Image taken from

The Saffron War

As already mentioned, the Black Death during the 14th century drastically increased the demand for saffron in central and northern Europe to a level that local suppliers could not meet. The only other major producers at the time were Arab sources, who were unwilling to trade due to hostilities over the crusades. This left Greece as Europe’s primary supplier.


The sale of saffron quickly made merchants extremely wealthy and powerful, which disturbed the declining aristocracy. In an attempt to regain control, a group of nobles seized a large saffron shipment heading to Basel in Switzerland. The stolen cargo would be worth over £300,000 in today’s market. The theft triggered a 14 week long war, named the ‘Saffron War’ that lasted until the shipment was returned. Though the cargo was returned in this instance, the saffron trade was plagued with thieves for the majority of the 13th century. Pirates would target saffron bound for Europe, often ignoring ships loaded with gold in preference for this profitable spice.


Decline and Modern Revival

Trade of Crocus sativus began to dwindle for a second time during the 18th century. There have been a number of causes suggested for this decline, including fungal diseases destroying crops, cold winters and to traders offering steadily lower prices in an attempt to outcompete their rivals. By the middle of the 20th century, the crocus started to become primarily grown for ornamental purposes. The use of saffron as a spice fell out of fashion and the only areas in which it endured were southern France, Italy and Spain.

Materia Medica jar containing saffron.
Materia Medica jar containing saffron.

Since the turn of the millennia in 2000, saffron has been making a comeback. Today, rather than being predominantly grown in Greece and Europe, the majority of C. sativus is now grown in Iran and North America.