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

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.

Opportunists

Last autumn I watched a bulldozer scraping away topsoil to level an area of building land, and made a mental note at the time to return this year to see what opportunist plants had established themselves on the bare soil. This one, common field speedwell Veronica persica, was well represented there. Usually the lowermost petal in this species is much paler, but this particular individual had exceptionally vivid blue flowers with deep blue, heart-shaped stamens. This species is an alien and was first recorded in Britain in 1825, and I imagine that its small seeds arrived on birds' feet, unlike .....

... this common sowthistle Sonchus oleraceus that must have staged an airborne invasion with its parachute-equipped plumed seeds.

I've been walking past this piece of land long enough to remember when it was arable land, with a wheat crop, and several of the other opportunists probably germinated from the residual seed bank of arable weeds in the soil ..... like this red-leg Persicaria maculosa....

...... this fumitory Fumaria officinalis ....

... and this field pansy Viola arvensis.

All of these are common and would be classified as weeds if they were competing with crop plants, but as colonisers of disturbed bare ground they're classed botanically as ruderals - species with constantly shifting populations that colonised disturbed habitats before more permanent vegetation establishes itself.

Common they may be, but the world would be a poorer place without them and just occasionally something a little less common reappears when the soil is disturbed.......

...... like this henbit Lamium amplexicaule which is much less abundant than it once was, thanks to the use of herbicides in intensive agriculture.