Stubble field annual wild flowers

 Some common annual wild flowers that flourish along field margins, in the few weeks between a cereal crop harvest and the arrival of the plough.

Common poppy, rejuvenated by warm sunshine, after the very wet weather during this summer's harvest in Teesdale

The tiny, pale blue flowers of field forget-me-not. Many  arable weeds have small flowers but are well worth a closer look.

Scarlet pimpernel has a long flowering period that often extends until the end of October. The flowers always close in mid-afternoon, unless rain clouds cover the sun, when they close quickly to protect their pollen -  behaviour that has earned the plant the reputation as 'the poor man's weather glass'.

Field pansy, a tiny but beautiful flower that has contributed to the parentage of garden pansy

Sky-blue flowers of common field speedwell, a native of the Caucasus that was first recorded in the wild in England in 1826 and has since spread throughout Britain. Like many arable weeds, its seeds are transported far and wide in mud on shoes, hooves and agricultural vehicle wheels. 

Common cudweed, with silvery leaves and tiny yellow flowers.

Common sowthistle whose light seeds, supported by a parachute of hairs, are carried long distances on the breeze

Bumblebees and poppies: do they see red?

 Human colour vision allows us to see a spectrum of colours that extends from violet to red - the colours of the rainbow - but bumblebees' colour vision is different. They can see ultraviolet, at the short wavelength end of the spectrum, but don't perceive the colour red at the long-wavelength end. But they are constant visitors to scarlet poppies in my garden, so there must be another cue that attracts them from a distance. My guess is that the lure must be a chemical one, a scent that they can detect but we can't, although the contrasting dark whorls of stamens in the centre of the flower would also  be visible to the visitor once they are close enough to see inside the flower. 

I watched this bumblebee make multiple attempts to find its way into the poppies waving in the wind, and once it found its way inside I could hear it buzzing, to shake pollen from the mass of stamens in the centre of the flower. You can see the bluish-grey poppy pollen packed into pollen baskets on its hind legs in these photographs.

Arable weeds

A ripening field of wheat, as harvest time approaches, is an impressive sight - the culmination of 10,000 years of selective plant breeding, aided by the finest agricultural technology that modern science can provide. It's also one of the most hostile environments for native wild flowers.

In winter the soil is ploughed every year and then selective herbicides are used to destroy any wild plant species that manage to germinate. but around the edges of the crop, where the herbicide spray doesn't quite reach, and where there is more light and less competition with the wheat, a select assemblage of annual arable weeds often persists. There presence in arable fields is as old as agriculture itself.

Corn poppy Papaver rhoeas depends on the plough to bring its tiny buried seeds to the surface, exposing them to the light that they need for triggering germination. Most scatter their seeds from their pepper pot seed capsules long before the combine harvester arrives.

Field pansy Viola arvensis is a frequent annual arable seed of crop edges. Its dome-shaped seed capsules split into three boat-shaped segments. They immediately begin to shrink as they dry in the sun, squeezing the seeds - which as smooth and slippery as wet soap - until their are fired out into the surrounding crop.

Most of these arable weeds have small flowers, nonetheless beautiful when you take a close look. This is cut-leaved cranesbill Geranium dissectum. Its tiny flowers are attractive but .....

.... its fruits are exquisite too. Here they are, ripe and ready to go - five seeds each in their own capsule, attracted to a strip of tissue that runs right to the tip of that beak-shaped structure. It becomes as tense as a clock spring as it dries, until the capsules break free and are flicked upwards, hurling out their seeds like a medieval siege catapult.

After the seeds have been discharged the fruits remain attached to the plant, like miniature chandeliers.

Most of these small arable weeds have no impact on crop yield, but sometimes more serious agricultural weeds survive and can become a problem - this is wild oat Avena fatua, whose seeds have a remarkable ability to drill themselves into the soil, which you can see by visiting this post.

The Itinerant Flora of a City

Every year the cityscape of Newcastle changes, as old buildings are demolished and the legacy of polluting industries from the past is cleared away. This site is in the Lower Ouseburn valley, once the location of a devil's caudron of industrial pollution but soon to become the site of 76 energy efficient 'green' homes. 

The patch of land in this picture has been derelict for several years - just a pile of broken bricks and earth bulldozed and then left, so that temporary colonisers took over.

Two years after the land was bulldozed, in the summer of 2011, it hosted the finest display of dyers rocket aka weld Reseda luteola that I've ever seen.

The site was so densely covered with this bee-friendly biennial that I wondered whether it might be the legacy of these plants being used in dye production in the 19th. century; in his New Naturalist book Weeds and Aliens Sir Edward Salisbury suggests that the plant's abundance and distribution often suggests that large populations are relicts of the plants' former cultivation. They have a vast seed output (Salisbury quotes up to 76,000 seeds per plant) and it's possible that the seed could have remained dormant for many decades.

There was also a good display of corn poppies amongst this temporary urban field of wild flowers. Their seeds germinate in even the smallest area of waste ground in Newcastle when they are brought to the surface by soil disturbance and exposed to light and moisture. 

Now that the site has been levelled and the rubble taken away, these plants will be on the move again - carried as seeds in rock, bricks and soil that have been taken away and probably used at another site in another part of Newcastle - part of the itinerant flora of the city.

Here's a sight you don't see very often....

If you happen to be travelling out of Durham along the dual carriageway towards Darlington, pull into the lay-by and take a look at the fields on your left as you travel down from what used to be called the Cock 'o the North towards Croxdale. You still sometimes see arable fields with fine displays of poppies when their seeds are brought to the surface by the plough, but it's rare to see displays like this.

 

This land was formerly sown with cereals and oilseed rape but was bought by the Woodland Trust a few years ago. Eventually it will all be replanted as public-access woodland, to join up with the fragments of ancient woodland you can see in the distance in these photographs.

  

In the meantime some of it it has been sown with the kinds of arable field wild flowers that were a common sight before the days of intensive farming - corn poppy, corn chamomile, corncockle, cornflower.

It's a wonderful sight - well worth stopping to have a wander through if you happen to be passing - there's a gate in the fence near the lay-by. I've uploaded these photographs larger than usual - so it you double-click on the images you'll get a better impression of the spectacle.

Three-headed Monster

We found this three-headed corn poppy in Teesdale this morning. Sometimes abnormalities like this can be caused by herbicide sprays but, since there were other perfectly normal flower stems on the same plant, I think this was simply a chance developmental aberration. The flower stem is flattened like a plank - fasciated in botanical parlance - and this sometimes happens when growing points that would normally develop into separate shoots become joined together. There can be a variety of causes, including physical damage by an insect or pathogen, infection by the bacterium Rhodococcus (Corynebacterium) fascians, environmental shock or a genetic cause. There are other examples of fasciation here and here.

Here's a normal one...

Red, Yellow and Blue

There a few spectacles in the British countryside that rival a field of poppies in full bloom. There are two fields at Warkworth on the Northumberland coast that are currently ablazed with these scarlet flowers. Like many plants, poppies produce seeds that can remain dormant in the soil for decades. They require light for germination, so only burst into life after they’ve been brought to the surface by the passing of a plough. Poppies belong to a group of arable weeds that includes corn chamomile, corn cockle, corn flower, corn marigold, bugloss and henbit whose flowering depends on regular soil disturbance, so they have always been a feature of agricultural landscapes since farming first began. In Victorian times all these species were very common, but the development of efficient seed cleaning technologies for cereal crop seed production and the advent of effective modern herbicides have removed them from fields so efficiently that many are now rare. Poppy’s vast seed output has been its salvation. Poppies survive seed burial for long periods and are often revived temporarily when new roads are cut through former agricultural land, or when grassland that was long ago planted with wheat and barley is freshly ploughed.

Behind the dunes at Warkworth, about half way to Alnmouth, there's currently another wonderful floral display in a patch of swampy ground. A single yellow flag iris (above) is a thing of beauty, but half an acre of them in full bloom is something else.......

And a little closer to Warkworth, in a corner of a field that has been left unplanted, there's the most stunning display of bugloss, a cornfield annual that occurs sporadically in the North east but here grows in such abundance that about a quarter of an acre is tinted with forget-me-knot blue.

We lament the fact that some individual wild flower species are becoming rare, but it's even more regrettable that massed floral spectacles like this, once common, are now few and far between...

Weeds or Wildflowers?

Every summer Durham University Botanic Garden hosts a wonderful display of annual cornfield weeds (or wild flowers, depending on your point of view). These are species that would have been familiar to Iron Age farmers but have now all but disappeared from the agricultural landscape, thanks to improved methods of cereal seed cleaning and decades of intensive use of systemic herbicides that wipe out weeds soon after germination and never allow them to set seed, so that the bank of seeds in the soil is finally depleted and the species become locally extinct. In Victorian times, when the main method of weed control was manual labour, all these species were serious weeds of crops that drastically reduced crop yields. The cornfield border is the most stunning exhibit in the Botanic Garden at this time of year, eclipsing even the giant Amazonian waterlilies in the glasshouses for their sheer ‘wow’ factor, and is a reminder of what has been lost from the agricultural landscape. Shown here, top to bottom, are corn poppies; corn marigold; cornflower; corn chamomile;corncockle. The whole border positively hums with bees and hoverflies. These are all easy species to grow in a wild flower garden. For more information about Durham University Botanic Garden visit http://www.dur.ac.uk/botanic.garden/