Sweet pea is a
flowering plantThe flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
in the genus
LathyrusLathyrus is a genus of flowering plant species known as sweet peas and vetchlings. Lathyrus is in the legume family Fabaceae and contains approximately 160 species. They are native to temperate areas, with a breakdown of 52 species in Europe, 30 species in North America, 78 in Asia, 24 in...
in the family
FabaceaeThe Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...
(
legumes), native to the eastern Mediterranean region from
SicilySicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...
east to
CreteCrete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...
.
It is an
annualAn annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...
climbing plant, growing to a height of 1–2 meters (nearly six feet and six inches), where suitable support is available. The
leavesA leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are pinnate with two leaflets and a terminal tendril, which twines around supporting plants and structures helping the sweet pea to climb. The
flowerA flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are purple, 2-3.5 centimeters broad, in the wild plant, larger and very variable in colour in the many
cultivarA cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s.
The
Sweet Pea L. odoratus, an annual, may be confused with the
Everlasting Pea L. latifolius, a perennial.
Horticultural development
Henry EckfordHenry Eckford was the most famous breeder of sweet peas, transforming the plant from a minor horticultural subject into the queen of annuals. Liberty Hyde Bailey called him "the prince of specialists". In 1888 He moved to the town of Wem in Shropshire...
(1823-1905), a nurseryman of
ScottishScotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
descent, cross-bred and developed the sweet pea, turning it from a rather insignificant, if sweetly scented flower, into the floral sensation of the late Victorian era.
His initial success and recognition came while serving as head gardener for the
Earl of RadnorEarl of Radnor is a title which has been created two times. It was first created in the Peerage of England in 1679 for John Robartes, 2nd Baron Robartes, a notable political figure of the reign of Charles II. He was made Viscount Bodmin at the same time. Robartes was the son of Richard Robartes,...
, raising new cultivars of
pelargoniumPelargonium is a genus of flowering plants which includes about 200 species of perennials, succulents, and shrubs, commonly known as scented geraniums or storksbills. Confusingly, Geranium is the correct botanical name of a separate genus of related plants often called Cranesbills. Both Geranium...
s and
dahliaDahlia is a genus of bushy, tuberous, perennial plants native to Mexico, Central America, and Colombia. There are at least 36 species of dahlia, some like D. imperialis up to 10 metres tall. Dahlia hybrids are commonly grown as garden plants...
s. In 1870 he went to work for one Dr. Sankey of Sandywell near
GloucesterGloucester is a city, district and county town of Gloucestershire in the South West region of England. Gloucester lies close to the Welsh border, and on the River Severn, approximately north-east of Bristol, and south-southwest of Birmingham....
. A member of the
Royal Horticultural SocietyThe Royal Horticultural Society was founded in 1804 in London, England as the Horticultural Society of London, and gained its present name in a Royal Charter granted in 1861 by Prince Albert...
, he was awarded a First Class Certificate (the top award) in 1882 for introducing the sweet pea cultivar 'Bronze Prince', marking the start of association with the flower.
In 1888 he set up his development and trial fields for sweet peas in the
ShropshireShropshire is a county in the West Midlands region of England. For Eurostat purposes, the county is a NUTS 3 region and is one of four counties or unitary districts that comprise the "Shropshire and Staffordshire" NUTS 2 region. It borders Wales to the west...
market town of
WemWem is a small market town in Shropshire, England. It is the administrative centre for the northern area committee of Shropshire Council, which has its headquarters at Edinburgh House in the centre of Wem. Wem railway station is on the Shrewsbury to Crewe railway line...
. By 1901, he had introduced a total of 115 cultivars, out of total 264 cultivars grown at the time. Eckford was presented with the Royal Horticultural Society's Victoria Medal of Honour for his work. He died in 1906 but his work was continued, for a time at least, by his son John Eckford.
More recently, the association between the sweet pea, the Eckfords and Wem has been highlighted again. In the late 1980s, the Sweet Pea Society of Wem started an annual Sweet Pea show and the town has again taken the flower to its heart. Many of the street signs now carry a sweet pea motif and an area of the town is known as Eckford Park.
Cultivation
Sweet peas have been cultivated since the 17th century and a vast number of cultivars, such as
Spencer Giant (usually mixed colours), are commercially available. They are often grown by gardeners for their bright colours and the sweet fragrance that gives them their name.
Pests and diseases
The sweet pea plant does suffer from some pests, the most common being the
GreenflyGreenfly is the artist name of Lawrence Green, a drum and bass music producer and DJ from Reading, England. His music style leans towards the more soul/funk influenced styles of drum'n'bass. He is currently signed to and has been releasing music since 2001...
. These insects suck the sap out of the plants and reduce the growth and can spread incurable diseases. A virus called Mosaic virus is spread by greenfly which causes the leaves to turn yellow, new shoots become distorted and flowering stops.
A pest called the Pollen Beetle which are small, shiny black beetles, eat the pollen and disfigure the flowers. Other pests include Caterpillars and
ThripsThrips are tiny, slender insects with fringed wings . Other common names for thrips include thunderflies, thunderbugs, storm flies, thunderblights, and corn lice...
. Another problem that is not necessarily a disease is
MildewMildew refers to certain kinds of molds or fungi.In Old English, it meant honeydew , and later came to mean mildew in the modern sense of mold or fungus....
, this is a white powdery coating that covers the leaves and slows down growth.
Toxicity
Unlike the edible
peaA pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Each pod contains several peas. Peapods are botanically a fruit, since they contain seeds developed from the ovary of a flower. However, peas are considered to be a vegetable in cooking...
, there is evidence that
seedA seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s of members of the genus Lathyrus, including sweet pea, are toxic if ingested in quantity. A related species,
Lathyrus sativusLathyrus sativus, is a legume commonly grown for human consumption and livestock feed in Asia and East Africa. It is a particularly important crop in areas that are prone to drought and famine, and is thought of as an 'insurance crop' as it produces reliable yields when all other crops...
, is grown for human consumption but when it forms a major part of the diet it causes symptoms of toxicity called
lathyrismLathyrism or Neurolathyrism is a neurological disease of humans and domestic animals, caused by eating certain legumes of the genus Lathyrus...
. However, as Lathyrus odoratus seeds are rarely ingested by humans in any quantity, there is little information on their toxicity to humans. However, sweet pea ingestion is thought to lead to similar symptoms, which have been called "odoratism", or "sweet pea
lathyrismLathyrism or Neurolathyrism is a neurological disease of humans and domestic animals, caused by eating certain legumes of the genus Lathyrus...
". symptoms of toxicity were portrayed by the character "alex supertramp" in the movie "Into the Wild".
In studies of rats, animals fed a diet of 50% sweet pea seeds developed enlarged adrenals relative to control animals fed on edible peas. The main effect is thought to be on the formation of collagen. Symptoms are similar to those of
scurvyScurvy is a disease resulting from a deficiency of vitamin C, which is required for the synthesis of collagen in humans. The chemical name for vitamin C, ascorbic acid, is derived from the Latin name of scurvy, scorbutus, which also provides the adjective scorbutic...
and copper deficiency, which share the common feature of inhibiting proper formation of collagen fibrils. Seeds of the sweet pea contain beta-aminopropionitrile that prevents the cross-linking of
collagenCollagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
by inhibiting
lysyl oxidaseLysyl oxidase also known as protein-lysine 6-oxidase is a protein that, in humans, is encoded by the LOX gene. Its inhibition can cause lathyrism, but, at the same time, its upregulation by tumor cells may promote metastasis of the existing tumor, causing it to become malignant and cancerous.-...
, leading to loose skin. Recent experiments have attempted to develop this chemical as a treatment to avoid disfiguring skin contractions after skin grafting.
Genetics
Gregor MendelGregor Johann Mendel was an Austrian scientist and Augustinian friar who gained posthumous fame as the founder of the new science of genetics. Mendel demonstrated that the inheritance of certain traits in pea plants follows particular patterns, now referred to as the laws of Mendelian inheritance...
is today recognized as the "Father of Modern Genetics" for his work with the cross breeding of
peaA pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Each pod contains several peas. Peapods are botanically a fruit, since they contain seeds developed from the ovary of a flower. However, peas are considered to be a vegetable in cooking...
plants (
Pisum sativum) with different characteristics, and sweet pea has been used in a similar way. The sweet pea is thus a
model organismA model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. Model organisms are in vivo models and are widely used to...
being used in early experimentations in genetics, particularly by the pioneer geneticist
Reginald PunnettProfessor Reginald Crundall Punnett FRS was a British geneticist who co-founded, with William Bateson, the Journal of Genetics in 1910. Punnett is probably best remembered today as the creator of the Punnett square, a tool still used by biologists to predict the probability of possible genotypes...
. It is highly suitable as a genetic subject because of its ability to self-pollinate and its easily observed Mendelian traits such as colour, height and petal form. Many genetical principles were discovered or confirmed in sweet pea. It was used by Punnett in early studies of
genetic linkageGenetic linkage is the tendency of certain loci or alleles to be inherited together. Genetic loci that are physically close to one another on the same chromosome tend to stay together during meiosis, and are thus genetically linked.-Background:...
. Complementary factor inheritance was also elucidated in sweet pea, from the cross of two pure-breeding white strains which gave rise to a blue hybrid, the blue colour requiring two genes, derived independently from the two white parents. Like the
blue roseBlue roses, often portrayed in literature and art as a symbol of love and prosperity to those who seek it, do not exist in nature as a result of genetic limitations being imposed upon natural variance. Traditionally, white roses have been dyed blue to produce a blue appearance. In 2004, researchers...
, the yellow sweet pea remains elusive, and a true yellow is unlikely ever to be achieved without genetic engineering.