Garden cress (Lepidium sativum L.),

    Water cress  (Nasturtium officinale L.) and

    Nasturtium (Tropaeolum majus L.)

Note

These three plants, only two of which are botanically related, have been combined into one document for their equal culinary merits. The term cress will henceforth be used for all three plants described in this document.

Synonyms for garden cress (Lepidium sativum)

 

Synonyms for water cress (Nasturtium officinale)

Synonyms for nasturtium (Tropaeolum majus)

Used plant part

Fresh leaves. Unripe nasturtium fruits can be pickled and used as a substitute for capers.

Plant family

Water and garden cress belong to Brassicaceae (cabbage family); nasturtium belongs to Tropeolaceae, a botanically not related family of its own.

Sensoric quality

Cress and its relatives display a spicy aroma and a refreshing, peppery-pungent taste lasting only a few seconds.

Main constituents

Similar to many other members of the cabbage family (black and white mustard, horseradish, wasabi), all cresses owe their aroma to isothiocyanates.
Nasturtium leaves contain glucotropaeolin (benzyl glucosinolate), which is enzymatically converted to the pungent benzyl isothiocyanate (C6H5-CH2-NCS), a compound closely related to the pungent principle of white mustard, but much more volatile and, thus, less persistent. In contrast, nasturtium seeds, contain glucoputranjivin, whose aglycon ist isopropyl isothiocyanate.
Water and garden cress, on the other hand, contain gluconasturtiin, which yields the 2-phenylethyl isothiocyanate (C6H5-CH2-CH2-NCS).

Since all these isothiocyantes are volatile and much susceptible to heat and moisture, cress aroma is most delicate; thus, cress leaves are never dried nor should they be cooked.

Origin

Garden cress probably stems from Western or Central Asia, where it is still found uncultivated. It is easy to cultivate and tolerates nearly every climate.

The cosmopolitan water cress is similar in taste and can, thus, be substituted by ordinary garden cress; water cress cannot be cultivated, but is regionally available by collecting the wild plant. Its aroma is sometimes described superior to other cress species.

Nasturtium stems from Southern America, probably Peru, and was introduced to Europe by Spanish conquistatores. Is is a common ornamental, but less used for cooking.

Etymology

The Greek name of cress, kárdamon, was loaned from Persia, where the garden cress probably originates; it is not related to English cress. The latter is either related to Lithuanian griezigs "pungent" or, which is far more probable, derives from the Indo-European root GRES "devour" whence also Old Norse kras "delicacy", Sanskrit grasati "he eats", Greek grân "gnaw". See also the etymology of grass (lemon grass).

On the other hand, nasturtium (a name used by the Romans for several cress-like plants, mostly garden cress) probably derives from nasi-tortium "nose pain" (from nasus "nose" and the verb torquere "torment") and refers to the sharp, pungent aroma.

Water cress bears in most languages an attribute meaning "water" (Italian acqua, Indonesian air) or "well" (German Brunnen, French fontaine), referring to its frequent growth in nonmoving water. The French, German and Spanish names of nasturtium all derive from Italian cappucio "hood; especially a monk's cowl", related to English cap; the name was given because the flowers of nasturtium resemble the cowl of Capuchin monks.

About the etymology of water, see water pepper.

English speakers, beware: Since Nasturtium is the botanical name of water cress and not of the plant commonly called nasturtium, there is much room for confusion. Especially, gluconasturtiin does not occur in nasturtium!
 

All cress species (which are approximately interchangeable in the kitchen) are popular in Europe an Northern America and used for spreads (especially such based on cottage cheese) and salads; simple bread with butter and fresh cress leaves tastes delicious. Less frequently, chopped cress leaves are topped on warm dishes, like vegetable soups or scrambled eggs. Whenever used, cress turns an everyday dish into an exquisite delicacy.

Cress leaves are not commonly combined with other fresh herbs; yet they are compatible with the fines herbes of French cuisine (see chives) and may be used together with each of them. Leaves or even more flowers of nasturtium are commonly used to flavour herbal vinegar (see dill); cress is also very good for herb sauces (see borage).

The obvious disadvantage of cress is that the leaves cannot be dried and are only rarely traded. While water cress must be gathered in the wild, both garden cress and nasturtium grow well in every garden with minimal effort. Garden cress is surprisingly unpretending and grows extremely quickly; about one week after sowing, the plant must be harvested. To have fresh garden cress at any time, use three pots and sow in three-day intervals. Nasturtium, on the other hand, needs only a little bit more care, but then may grow exuberantly for one season. Its orange flowers are very decorative and have additional use: The buds and unripe fruits can be pickled and serve as a good substitute for capers.