Sweet pea

Appearance

It is an annual climbing plant, growing to a height of 1–2 meters, where suitable support is available. The leaves are pinnate with two leaflets and a terminal tendril, which twines around supporting plants and structures helping the sweet pea to climb. The flowers are purple, 2-3.5 centimeters broad, in the wild plant, larger and very variable in colour in the many cultivars.

The annual species, "L. odoratus", may be confused with the everlasting pea, "L. latifolius", a perennial.

Defense

Unlike the edible pea, there is evidence that seeds of members of the genus "Lathyrus" are toxic if ingested in quantity. A related species, "Lathyrus sativus", is grown for human consumption but when it forms a major part of the diet it causes symptoms of toxicity called lathyrism.

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 scurvy 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 collagen by inhibiting lysyl oxidase, leading to loose skin. Recent experiments have attempted to develop this chemical as a treatment to avoid disfiguring skin contractions after skin grafting.

Cultural

Henry Eckford, a nurseryman of Scottish 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 Radnor, raising new cultivars of pelargoniums and dahlias. In 1870 he went to work for one Dr. Sankey of Sandywell near Gloucester. A member of the Royal Horticultural Society, he was awarded a First Class Certificate 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 Wem in Shropshire. By 1901, he had introduced a total of 115 cultivars, out 264 cultivars grown at the time. Eckford was presented with the RHS 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 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. There is also a cultivar 'Dorothy Eckford', named after a family member.