Bargemans Cabbage / Oil Seed Rape

Brassica

by Jeff Bevan · Published 28th April 2024 · Updated 28th April 2024

Yellow Power – Lansdown, Bath, Somerset, UK. ID 804_3170

Bit by bit Somerset seems to be going slightly more yellow. I’m not talking buttercups, cowslips or even primroses – but brassica plants.

Confusing Brassica

Brassica is a genus of plants in the cabbage and mustard family. I admit being confused over their identification. I have wrongly labelled them in previous posts. Here in Somerset there are probably three likely brassica candidates:

Oil-seed Rape (Brassica napus subsp. oleifera)
Black Mustard (Brassica nigra)
Bargeman’s Cabbage or Summer Rape (Brassica Rapa or Brassica campestris)

My currently understanding is – the yellow in fields is oil-seed rape, while the yellow alongside ditches on the Levels is bargeman’s cabbage. Black mustard is none of them. Of course, I could be wrong.

Where to find them?

Drive around our pleasant land at this time of year and you will see not just green but fields of yellow. Usually in different fields each year. Some years an area has lots of yellow other years the yellow has moved somewhere else.

Oil-seed Rape – Nr Ilchester, Somerset, UK. ID JB_4513

On the other hand bargeman’s cabbage grows across the countryside. It is often found lining the sides of the main rhynes such as below at the RSPB Ham Wall nature reserve on the Avalon Marshes.

Bargeman’s Cabbage – Ham Wall, Somerset, UK. ID JB_2528

Sometimes oil-seed rape can escape from its farm and spread out into the countryside. This can make identification confusing. I had assumed the yellow at Ham Wall was oil-seed rape, others have told me it was black mustard. Perhaps it is a mix of all three species growing together, or combination hybrid?

History

Bargeman’s cabbage is believed to have been introduced as far back as the Romans.

Bargemans Cabbage – Ham Wall, Somerset, UK. ID JB_2775

But in recent years it seems to be more common. Is this because of:

Climate change?
Recent changes in farming practice?
The way we now manage ditches?

Either way it is most common along the larger waterways from which it spreads down side ditches. It is now an established across the Somerset Levels.

River Sheppey – Nr Fenny Castle, Somerset, UK. ID IMG_3899

It has a distinctive colonisation pattern. It first appears on the banks of the main rhynes and then gradually spreads to smaller ditches. This may because the main rhynes are maintained more frequently and offer better conditions for colonisation. It also suggests seeds are being dispersed in the water and like Himalayan balsam are washed in from upstream. – Axe Brue Internal Drainage Board

Oil-seed rape has significantly increased in popularity since the 70s. Originally grown as a non-profit crop to restore the soil as part of field rotation. New uses such as bio-fuels has increased its popularity. But research has shown that in the last few years there has been a drop in the amount of oil-seed rape being grown. Maybe that will change as its price fluctuates.

Yellow Dawn – Sparkford, Somerset, UK. ID 804_3454

Why grow oil-seed rape?

Oil-seed Rape is grown for animal feed, vegetable oil for humans, and biodiesel. It is also grown as part of field rotation to rest soils.

Babcary in Yellow – Somerset, UK. ID 810_5641

Oilseed rape is a useful break crop, and with current favourable gross margins it can also provide many other benefits across the rotation. These include helping to reduce the threat of soil borne disease such as take-all, the opportunity to control some problematic grass and broadleaved weeds and with a long tap root it can help open-up the soil improving soil structure and porosity. The positive effects of using oilseed rape as a break crop will result in improved yields in the following cereal crop. – Farming Life

Environmental Impact

Bargeman’s cabbage can be thought of as a plant native to the UK. This is good news. On the other hand it is now spreading very fast and beginning to dominate some areas. So perhaps it is time to think about managing its spread. Maybe the way ditches are cleared could help control the spread of bargeman’s cabbage?

Red Admiral (Vanessa atalanta) – Ham Wall, Somerset, UK. ID JB_3006

When farmers grow oil-seed rape for profit, rather than to rest soils, it must be intensively managed to maximise profits. This means using a mix of pesticides. Despite offering a large source of food for bees there are concerns that these chemicals are having an impact on bee populations such as the numbers of bumble bees.

Bargemans Cabbage – Ham Wall, Somerset, UK. ID JB_2871

Genetically modified oil-seed rape could cross pollinate with bargeman’s cabbage creating hybrids that may spread their man-made genes across the countryside.

It raises questions about whether it is sensible to grow GM crops at all in countries which have wild relatives capable of producing hybrids and about the separation distances required between conventional varieties and GM crops to avoid contamination.

Apart from Bargeman’s cabbage, oil-seed rape has a number of other wild relatives which could produce fertile hybrids. Further work is being undertaken to see how widespread these other hybrids might become and whether they were also fertile, potentially being able to create a whole new race of herbicide resistant brassicas. – The Guardian

Long Yellow Drove – Long Drove, Nr Glastonbury, Somerset, UK. ID 804_4259

Photographing Yellow Fields

Sometimes fields of yellow are grown near a church or tree that provides a focal point such as at East Lydford.

Yellow Fields – East Lydford, Somerset, UK. ID 804_3547

Sometimes you have to search out an interesting feature such as an old barn.

Yellow Barn – Green Ore, Somerset, UK. ID 804_3763

Sometimes the annual rotation takes it to fields with no features. These provide an opportunity to recreate the Ukrainian flag.

Yellow Oilseed Rape fields – Shapwick, Somerset, UK. ID 807_1198

And finally…

Some hate the sight of oil-seed rape fields. What do you think? Feld rotation means it is not seen in the same place every year. Are you concerned about its spread into the countryside?