Rocket, Wild Rocket 'Olive Leaf'

Relatively unknown to our shores, Rocket ‘Olive Leaf’ is an excellent selection of the traditional Italian olive leaf wild rocket. Known as 'A Foglia Di Olivo', the foliage and flavour are both untypical of the wild rocket we have recently come to know.

Olive Leaf has a beautiful light green colour and smooth shape similar to an olive leaf, without the serrations usually associated with wild rocket. It has a distinctive aroma and more intense flavour than the cultivated types but the flavour is more subtle than the usual wild rockets.
This perennial form of wild rocket is very easy to grow. It is a drought tolerant, extremely cold hardy, evergreen. It has a prostrate habit and is resistant to bolting.

It seems strange that a peppery little leaf should have had such a big impact on cooking but, over the past ten years, nothing can quite beat rocket for its ubiquity. There is good reason for it, too. You can think of rocket in three ways: as a herb, as a salad leaf and as a wilted green, so if you’re a fan of its peppery bite, you can pretty much use it in anything.

Position:
Sow directly into a bed containing any good fertile, well drained soil. Use a line to mark out the row. Sowing in a straight line allows you to identify where your rocket seedlings are and which are the weed seedlings to pick out.
Sow just a small quantity at one time, and then sow successionally, to harvest over a longer period. A 1m (3in) row is usually enough to get you started. Late summer sowings will carry on cropping into the winter if the plants are protected by cloches.

Sowing:
Sow in spring for summer greens, and in autumn for winter greens.
Sow thinly 6mm (¼in) deep in drills spaced 45 to 60cm (18 to 24in) apart. Sow the seeds thinly along the row, spacing them out as evenly as possible. The distance between the seeds should be about 3cm. (1¼in) Cover the seed lightly with soil. Remove any weed remnants or large stones as you go to ensure the plants have a good start.
Water the seeds in well using a watering can with the rose attached. This means you drench the soil but minimise disturbance to the seeds.

Cultivation:
Flea beetle can be a problem in summer, nibbling holes in rocket leaves. The best defence is to cover the row with a length of horticultural fleece.
Rocket will always want to flower in summer, because this is the time of year when all crucifers naturally flower, then produce seed.
As autumn approaches, cover crops with sheets of horticultural fleece to keep the cold at bay, and you could be cropping right through to first frosts.

Harvesting:
Simply pick the young leaves and the plant will keep generating new ones for months. Older leaves are a bit tougher and hotter. Pick over the whole row rather than just one or two plants as this would weaken them.
As the flower buds appear pinch them out to prolong cropping. The flowers are small, yellow with dark centers and can be used in the salad for a light piquant flavour.

Storing:
Rinse the leaves in cool water and dry on paper towelling. Wrap leaves tightly in plastic or a zip lock bag. Best if used within two days.

Nutrition:
Arugula is a nutritional powerhouse, containing significant folate (folic acid) and calcium. Exceptionally high in beta carotene, vitamin C, and a good source of iron, Arugula is a member of the same family as cabbage and broccoli and like all such vegetables; it contains cancer-fighting phytochemicals called indoles.
You can substitute water cress for a similar peppery flavour. You can also use fresh baby spinach (but the flavour will not be the same). Also dandelion greens have a tart flavour but a bit more bitter.

Nomenclature:
Diplotaxis is from the Greek diplous, meaning ‘double’, and taxis meaning ‘row’, because of the double row of seeds in the seed pod.
Wild Rocket have the species name tenuifolia which means ‘with finely-divided, slender leaves’. While the species name of Olive Leaf Rocket, integrifolia indicates that the leaf margins are entire and uncut (or not toothed).
Eruca is a classical Latin name used by Pliny.
The term arugula (variations of Italian dialects around Arigola) is used by the Italian diaspora in Australia and North America and from there picked up as a loan word to a varying degree in American and Australian English, particularly in culinary usage. The names ultimately all derive from the Latin word eruca.
Vernacular names include Garden Rocket, Rocket, Eruca, Rocket salad, or Arugula (American English), In Italy, it can be known as Rucola, Rugola, Rucola gentile, Rughetta, Ruchetta or Rucola selvatica.
Throughout the world there are variations: Rauke or ruke (German), Roquette (French), Rokka (Greek), Ruca (Catalan), Beharki (Basque), Oruga (Spanish), Rúcula (Portuguese) krapkool (Flemish), Arugula Selvatica, arugula sylvatica, aeruca rocket, eruka psevnaya (Russian), oruga (Spanish), jaramago (Spanish), Roman rocket, salad rocket, sciatica cress, shinlock…

Rocket Explained:
The common name Rocket is used for at least twenty species of herbs, mostly members of the mustard family Brassicaceae. These species vary from well known and widely cultivated to obscure and rarely or never grown.
One of these plants is grown mainly for its beauty (Hesperis matronalis, ‘Dames Rocket’); the rest are considered edible salad herbs, wild or cultivated. They share in common a distinctive zesty or sharp flavour that is akin to mustard or horseradish.

There are two main types of rocket that we can find in supermarkets, often mixed together in the same package. The genus Eruca often known as 'Cultivated Rocket' and the genus Diplotaxis known as 'WIld Rocket' which is hotter in flavour. Over the past ten years, these peppery little leaves have had a big impact on cooking and the range of varieties available as seed is increasing year on year, the flavours between varieties vary tremendously.
The leaves, flowers and sprouted seeds are eaten. The flowers and leaves taste differently, try both; some people prefer one to the other.

Cultivated Rocket:
The most familiar in terms of current culinary usage is Eruca vesicaria, One of three species of the genus Eruca, native to parts of Southern Europe it is an annual plant with white flowers. It is often called Rocket, period, as if it was the only plant with that name. There are many other names for it, see above, but it is often simply known as Salad Rocket. With oval, softly serrated leaves, the small creamy-white flowers give rise to plump seedpods.

Wild Rocket:
No so familiar is the genus Diplotaxis. With 27 species, the genus includes both annual and perennial members. It is native to Central & South Europe, NW Africa, Crimea, North & West Turkey, Caucasia and West Syria.
This species is well known as an ingredient in salads composed of so called wild greens. It is often called Wild Rocket or Wild Arugula, Perennial Wall-Rocket, Narrow-leaved or Wall-Mustard, Various seed vendors have sold it as Rucola Selvatica. a sort of fake scientific name / Italian name. It has also been offered as Arugula Sylvetta.
There are a number of varieties available as seed. These drought-tolerant, evergreens have a prostrate habit and are resistant to bolting. With pure yellow flowers and slender seedpods and they taste hotter and more aromatic than the varieties of Eruca.
D. tenuifolia is the most well known Wild Rocket, with dark green, deeply notched leaves that are prized as salad ingredients because of their pungent aroma and flavour.
D. integrifolia is a traditional Italian variety also known as ‘Olive Leaf’ Wild Rocket with light green leaves that are smoothand elongated shaped.