Wild brassica is a common name for a number of related species, all edible, all introduced and naturalised, all with a similar flavour profile. Many of the Brassica species are now interbreeding, creating various hybrids and localised colonies.

The easiest way to approach this group of plants is by empowering yourself with knowledge of the typical identification features. Once you’ve confirmed a plant is one of the wild brassicas, try it for yourself, as the taste varies from a spicy mustard to bland cabbage flavour.

The most common weed species of the brassica family in south-eastern Australia are wild turnip (Brassica tournefortii), field mustard (Brassica rapa), wild cabbage (Brassica oleracea), Indian mustard (Brassica juncea) and rapeseed (Brassica napus). Many of these wild weeds have been domesticated over the centuries and their cultivated form are now our common vegetables, making the distinction between weed and useful plant quite blurry.

Don’t feel overwhelmed – you just need to familiarise yourself with some key features and then off you go, free veggies forever!

How to identify wild brassicas

Wild brassicas are annual or biannual plants, bright emerald green to dark olive in colour. Usually growing to 0.5 metre tall, they sometimes reach 1.5 metres when in full flower.

Leaves

Wild brassicas have variable leaves, smooth when young but developing bristle-like hairs when older. The lower leaves can be quite wide and up to 30 centimetres long, while the leaves developing up the flowering stalks are noticeably smaller.

Flowers and seeds

The flowers are the distinguishing feature, as they have a cross-like shape, formed by four petals – usually yellow, but sometimes white or pink– with a central cluster of six stamens- four tall and two short (stamens being the male part of the flower) surrounding a single pistil ( the female part of the flower). The flowers range from a few millimetres wide to 25–30 millimetres, depending on species and conditions. If you see a yellow-flowered, low-lying weed, come closer –if the flowers have the distinctive cross shape, chances are this is a brassica. The seeds are formed in elongated seed pods that resemble tiny beans pointing upwards (silique); they can be differentiated from the bean family (Fabaceae), as inside they have two chambers, with seeds distributed between them. Have a look at the diagram of common weedy plants of the brassica family (Brassicaceae) from the Weeds Society of Western Australia for some guidance.

As food

All wild brassicas are edible, but they vary greatly in flavour, depending on where they grow or the traits of the particular colony. At times they can be quite bitter.

Another important aspect to consider is texture. While the very young leaves are usually good as a raw addition to salads, the older leaves quickly become fibrous and hairy, and are best enjoyed cooked or fermented. In my opinion the most delicious and easiest-to-use part of the plant are the flowers, always abundant throughout most of the year. They are fresh and juicy, and distinctively cabbage-flavoured, but nevertheless pleasant as a snack when out in the fields (or used as a colourful garnish for a dish).

Brassicas are a highly respected vegetable, providing nutritious amounts of vitamin C, vitamin K, magnesium and soluble fibre.

The domestication of wild mustards

We have enjoyed this family as food all over the world. They are some of the earliest vegetables that by now have been transformed into all sorts of greens that we regularly buy and consume from our greengrocer and supermarkets.
Various cultures around the world transformed parts of the plant into cultivated greens, including the roots ( turnip, swede, kohlrabi) the leaves (cabbage, mustard greens, bok choi, brussels sprouts, kale) flower buds ( broccoli, cauliflower) and seeds ( mustard, canola, rapeseed).
The reasons for selecting the wild plants as our food sources are many, including:

• They tend to be annual or short-lived, growing fast when conditions are right.

• They love disturbed soils, being quite adapted to creating fungal partnerships even in very poor conditions.

• They interbreed readily, allowing for a fast selection of preferred traits.

• The seeds remain viable for several years, allowing for safe storage when the conditions for growing food are not ideal.

We love the brassicas so much that they are now one of the most prominent group of plants in our diet and we’ve been eating them for so long that we are now conditioned to digest the nutrients from this family, as a co-evolutionary process. When your mother used to say ‘eat your greens so you become big and strong’, this almost exclusively meant brassicas.

One example for all is Brassica rapa, a wild turnip that was repeatedly domesticated from the Mediterranean across to India from as early as 2000 BC. Edible turnips were possibly first cultivated in northern Europe, and were an important food in ancient Rome. The turnip then spread east to China, and reached Japan by 700 AD. There are descriptions of B. rapa vegetables in Indian and Chinese documents from around 1000 BC. You can read the amazing work in agricultural archeology in books like The Cultural History of Plants as an example. Fascinating and humbling at the same time.

Four common wild brassicas

African mustard - Brassica turnefortii
This is by far the most widespread of the wild brassicas and much-hated weed in agricultural land, particularly where the soil is tilled. The seeds remain viable in the ground for several years and can withstand fire. It is particularly active where the soil is disturbed such as on roadsides and in damaged ecologies. In its native range of northern Africa, this mustard has always been harvested for food.

Wild turnip - Brassica rapa

This plant has been domesticated over the past 3-4 thousand years into various common vegetables, including turnip, cabbage, napa and bok choi. The wild version maintains higher nutritional values but is often tough and hairy. We do not know the original range of this plant as the domestication happened several times in various parts of the world and cultivated strains escaped back into the wild several times, interbreeding with other local colonies. It is now considered a cosmopolitan plant.

Wild cabbage - Brassica oleracea

The wild origin of broccoli, cauliflower, kale, Brussel sprouts, kohlrabi and more. It is the wild brassica with the widest leaves, making it an excellent harvest. Greens are best to collect when young and flower heads are great eating too. It can form dense infestations in agricultural land and market gardens, competing for nutrients. Originally from the Mediterranean basin, wild cabbage is now a worldwide weed found popping up from disturbed land. It can cope with high salinity soils, a feature that allows it an advantageous edge over other plants, especially in salty coastal areas.

Indian mustard

This plant has been bred to create several greens commonly eaten by many cultures including leaf mustard or gai choi, Korean red mustard, curly-leaf mustard, mustard greens and mizuna. Indian mustard tends to have a stronger, spicier flavour.

Other closely related wild brassicas

There are several other wild plants of the brassica family ( Brassicaceae) growing wild in Australia, predominantly in disturbed environments, agricultural settings and along roadsides. They all have the same flower structure of four petals and 6 stamens, but are not true brassica species as such. The main differences are in the fruits (seedpods), so pay attention and familiarise yourself with your local colonies ( see above for a diagram of the main varieties in Australia). Other similar species are turnip weed - Rapistrum rugosum, hedgemustard - Sisymbrium species, peppercress - Lepidium species, beach mustard - Cakile species and shepherd purse - Capsella Bursa-pastoris.

Recipes

We collected a bunch of Mediterranean brassica leaves - Brassica incana as it is quite abundant at the moment where we live, Western slopes of NSW. Marnee and I talked a lot about what recipe to come up with for the blog and decided to settle on a tried and tested modern favourite, a take from the ever popular kale chips. We made wild brassica cheesy crisps! Simple, effective, quite yummy and morish. WIld mustards are a common invasive, so no one will mind you going around and collecting as much as you can. Enjoy!

Wild Brassica Cheesy Crisp

Prep : 15 minutes
Cook: 30-45mins

Ingredients:
We harvested about 100grams of wild mustard (brassica) leaves.
Olive oil
2 tspns ground sea salt (reduce if desired)
2 tbsps nutritional yeast
Juice of ½ lemon

Method
• Pre-heat your oven to 150 degrees
•Separate the leaf from the stalk. Each side of the leaf should tear away easily.
•Wash your leaves well and place them in a clean, dry mixing bowl.
•Pour on enough olive oil to coat all the leaves.
•Add the salt, nutritional yeast + lemon juice and mix well, massaging all the ingredients until the leaves have reduced down. Taste a leaf and adjust the seasoning if needed.
•Spread your leaves on a sheet of baking paper laid out on a good sized baking tray. It’s ok to overlap your leaves.
•Place the tray in your oven for 15mins
•Now take your tray out of the oven and turn your leaves. Put back in the over for a further 15mins.
•Repeat the last step once more if you want even crunchier.
•Set aside to cool and reach their full crispy potential.

Recipe by @marneefox of @foragetofeastaustralia

Reference

vdoc.pub > Downloadable book on the history of wild plants
Wiki > on the brassica family
Gallowaywildfoods.com > Excellent overview of edible brassicas by a fellow forager in the UK
Avh.ala.org.au > Mapping service of wild plants in Australia
Amnh.org > Detailed diagrams to understand how to identify flowers and its parts
Plants for a Future > extensive database for edible plants in the world
Weeds Society of Western Australia >Diagrams of brassicas fruits for ID > https://www.wswa.org.au/western_weeds/brassicaceae.htm
Pubmed.gov >Scientific study proving how the plants in the brassica family are safe and beneficial to eat.
National Library of Medicine > Study detailing how brassica species are safe to eat
Mind Body Green > Health benefits of the brassicas
Sciencedirect.com > Health benefits of wild mustard