Papaver rhoeas 'Mother of Pearl'.

Cedric Morris was an idiosyncratic genius who painted flowers. He painted portraits too, and landscapes, and birds, from wood pigeons to sparrowhawks and herons. But he always returned to flowers. For the painter, who died 30 years ago, was equally well known in his lifetime as a plantsman.
For Morris, painting and gardening were connected from the outset. He failed to recognise artificial distinctions between his twin focuses. Gardening shaped his painting: his painting influenced his plant-breeding. Today his vitality survives not only in his painting but his plant introductions and those plants named after him, an impressive tally that includes a rose, a geranium, a daffodil, irises and, of course, poppies.

In his gardening, as in his painting, Morris’s preoccupation was with colour. He tramped the Suffolk countryside looking for poppies, not for the obvious scarlet, nor for the Shirley Poppy that had been developed earlier in the 1880's, but for softer colour variants, for pearl tones and smoky tints. The pink of raspberry fool, the blue-grey of a wood-pigeon's wing and gentle purples that catch the changing tones of a summer sky.
His selections were developed in his Suffolk garden around 1910. Happily his selections of this cult flower are still available to us all, occasionally found marketed as ‘Sir Cedric Morris’ but most often as 'Mother of Pearl' it is still one of the most distinctive, yet subtle blends of single flowered poppies available today. The finest colours in mauves and smokey tones. Smokey dove greys, blackberry and lavender, mauve edged in white, and opalescent shadowy tints.

They are the easiest thing to establish, as long as you can provide light soil in full sun or light shade. Simply scatter the seeds thinly in either spring or in autumn and gently rake them in.
Sown once the ground has begun to warm in late April, by June you will be blessed with the goose neck, prickly buds and shortly after, gorgeous pearl greys, pewter and mauve coloured, luminescent blooms.

Sowing: Direct sow in spring or in autumn.
Sow outdoors from spring to early summer or in the autumn for flowering the next season. staggered sowings through spring will extend the flowering season. Seeds are best sown directly where they are to flower in short drills 12mm (½in) deep at around 20°C (68°F). Cover lightly with soil, if sowing more than one annual in the same bed, mark the sowing areas with a ring of light coloured sand and label
Seeds germinate in less than two weeks. The seedlings will appear in rows approx 6 to 8 weeks after planting and can be told from nearby weed seedlings quite easily. Thin the seedlings out so they are finally 4 to 6 in apart by early summer.
Alternatively, leave them to grow as small clumps, of 4 to 6 plants every 30cm (12in) or so. Compost should be kept slightly moist, but not wet at all times.

Cultivation:
Prefers well drained soil enriched with manure or compost ahead of planting. Feeding is rarely needed but water well if there are prolonged periods of drought.
Remove spent flowers to encourage prolific blooming. At the end of the season, if required, leave a few plants to die down and self seed. Others can be pulled up and composted

For Cut Flowers:
Cut when flowers are in bud, hold the base of the stems for a few seconds in a flame or boiling water, and the flowers will last several days in water.

Plant Uses:
Cottage/Informal Garden, Flower Borders and Beds, Wildflower meadows, Butterfly & Bee Gardens, Cut Flowers.

Origin:
The origin of Papaver rhoeas is not known for certain. As with many such plants, the area of origin is often ascribed by Americans to Europe, and by northern Europeans to southern Europe. The European Garden Flora suggests that it is ‘Eurasia and North Africa’; in other words, the lands where agriculture has been practiced since the earliest times. It was probably introduced into Britain and Ireland along with agricultural crops at least as far back as the Late Bronze Age. It has had an old symbolism and association with agricultural fertility.
Common poppy is found on a wide range of soils but is most frequent on light, calcareous soils. It is a species of flowering plant in the poppy family, Papaveraceae and is pollinated by insects, particularly bumble bees.

Nomenclature:
The genus name Papaver is the classical Latin name for the poppy
The species name rhoeas is probably derived from the Latin word 'rho' meaning red.
Sir Cedric Morris (1889-1982), the artist who gardened at Benton End in Hadleigh, Suffolk, bred his own series of poppies in muted shades of grey, lilac and purple. Developed around 1910, and originally marketed as ‘Sir Cedric Morris’ they can now be found under the names of 'Mother of Pearl' and occasionally 'Fairy Wings'.
In some European countries this strain can also be found with the Dutch name of 'Parelmoer', the literal translation meaning 'pearl-shell'.
In 1980 Thompson & Morgan used the 'Mother of Pearl' strain to produce the fully double 'Angels Choir Mixed’ strain. It took 10 years to develop and select, and is marketed as 'Dawn Chorus' in some countries.

Sir Cedric Lockwood Morris (1889-1982):
Cedric Morris was a Welsh artist who painted plants – showy, colour drenched, often densely packed, floral arrangements. He was also a plantsman, cultivating a garden in Suffolk where he bred thousands of irises. His painting Iris Seedlings (1943) held by the Tate, no doubt inspired by the latter pursuit. He was rewarded for his application at the highest level, with a great number of cultivars taking his name.

The RHS Horticultural Database lists the following cultivars:
Rosa ‘Sir Cedric Morris’
Pulmonaria ‘Cedric Morris’
Papaver rhoeas ‘Cedric Morris’
Papaver orientale ‘Cedric Morris’
Narcissus ‘Cedric Morris’
Hemerocallis ‘Cedric Morris’
Geranium sanguineum ‘Cedric Morris’
Fritillaria pyrenaica ‘Cedric Morris’
Ferula tingitana ‘Cedric Morris’
Dianthus ‘Cedric’s Oldest’
Colchicum speciosum ‘Cedric Morris’
Agapanthus ‘Cedric Morris’