Watercress (Nasturtium officinale) is best known as a salad vegetable but is botanically classed as a herb. It belongs to the family Cruciferea (Brassicaceae) along with other vegetables such as cabbage, broccoli, brussels sprouts, cauliflower and kale and is related to mustard. An aquatic or semi-aquatic hardy perennial, it can be found growing naturally in profusion near springs and running water such as streams.
Origin and history of watercress
Native to Europe and central Asia, watercress one of the oldest known leaf vegetables known to man and can be traced back more than 3,000 years, to the Persians and Ancient Greeks.
Not only is it mentioned in Cretan legend where it is said to have been eaten by the god Zeus for fortification, but it has also been well documented certainly as far back as 485BC when Xerxes, a Persian Emperor ordered that his soldiers be given watercress to keep them healthy during their long marches and as a preventative against scurvy and further when Hippocrates is said to have grown watercress for medicinal purposes on the Island of Kos around 400 BC where he founded the first hospital.
The Romans too revered watercress and it is said that Emperors would eat it to enable them to make “bold” decisions. Anglo-Saxons made watercress broth to ‘spring clean’ the blood and it is believed that Irish monks called it “pure foods for sages” and survived for long periods eating only bread and watercress.
Many people think of watercress as being a particularly British ingredient. Watercress soup, which gained favour in the 1700s in England is still a favourite. Indeed, at one time it played a significant part in the diets of the working classes who often ate it with bread for breakfast. It was so popular that some more enterprising people bought it in bulk from the markets then formed it into “one portion” bunches which they would sell on to individuals as handheld “food on the go”.
Watercress has seen a surge in popularity in the last few years, especially since Liz Hurley (actress) mentioned in 2001 that she relies on watercress to maintain a nutritious diet. More recently, the results from two years’ research carried out by the University of Ulster showed it to have extraordinary medicinal qualities, in particular relating to the reduction in DNA damage to white blood cells, considered to be an important trigger in the development of cancer.
Furthermore, watercress contains beta-carotene, a host of vitamins (A, C, B1, B6, K and E), iron (more than spinach) , calcium (more than milk), magnesium, manganese, zinc, Lutein and Zeaxanthin, types of carotenoids that act as antioxidants. Add to those the fact that it’s low in calories and it’s easy to see why it has gained the accolade of being a “super food”.
Cultivation of watercress
The fact that watercress wasn’t commercially produced until the 1800s tells us something about its cultivation. Being a semi aquatic plant, it’s not easy for most of us to grow and even if you are lucky enough to own a spring or stream, the fact that it’s susceptible to river fluke and poisoning through contaminated water can make it a difficult plant to cultivate.
An alternative for home cultivation is land cress which is generally considered a reasonable substitute for watercress and can be grown easily in the garden or in pots. Also a perennial, it requires semi shade and a moist soil, however it doesn’t like to be waterlogged for long periods of time.
In the UK, much of the commercially cultivated watercress is is grown in shallow gravel beds. These are fed by a constant flow of spring water from springs and bore-holes which is chalk filtered. The seeds are germinated on thin layers of compost in greenhouses and polytunnels and then transplanted into the gravel beds by hand.
Gradually pure spring water is introduced to the bed in increasing amounts culminating in 5,000 gallons per acre per hour throughout the growing period which takes from 28 to 70 days depending on weather conditions.
Once ready for harvesting, specialised machines are used which cut up to three tonnes of watercress an hour. The plants are then transferred to packing houses, which are close to the watercress farms to ensure that the watercress is chilled and packed into bags ready for immediate transport to outlets within a few hours which is imperative as watercress is a delicate and highly perishable vegetable.
Buying, storing and preparation of watercress
As mentioned above, watercress a highly perishable item and doesn’t last for many days, even when refrigerated. It is therefore advisable to only buy small quantities at a time. Trim the stems if required then rinse in cold water and dry very well in a salad spinner or on paper towels. Place in a plastic bag and refrigerate. Keeps for up to 4 days. To refresh, discard any bruised or yellow leaves and submerge in iced-water until revitalised.
Watercress in Cooking
Watercress is used in many cuisines worldwide from soups to stir fries. It is also often used as a delicious edible garnish to meat, poultry and fish and can be used as a salad ingredient much like lettuce.