SWEET PEA, an annual herb (Lathyrus odoratus) of the family Fabacetr. It is sup posedly a native of Ceylon, Sicily and Sardinia, the original pink-and-white and the red varieties being credited to the first country and the pure white and purple varieties to the other two islands. The known history of the plant begins in 1650, and the first record of its cultivation in 1699, when Father Franciscus Cupani grew it at Panormus, Sicily. By 1730 the seed was com mercially known, and about 60 years later five varieties were offered by a London secdsman. Until Henry Eckford commenced experimenting in 1876 for the production of new varieties there were, however, rarely 12 varieties offered in any one year. Largely due to his efforts the list of varieties had risen to 150 in 1898, and the popularity of the flower had vastly extended. It has been estimated that since 1900 the aver age annual crop of sweet-pea seed is about 100,000 pounds, about one-fifth of which is produced by one company in California, where nearly all the seed used in Europe and America is now grown.
The sweet pea is a hardy annual herbaceous vine with rough, winged stems, tendril-bearing leaves composed of two leaflets borne on long stalks, and fragrant papilionaceous flowers of various shades, ranging from white to blue and red through many tints, and including both double and °hooded" forms. The pods are about two inches long, and contain about six brown seeds. The double varieties are not regarded with favor, being rather unkempt and lacking the daintiness of the single sorts.
For best results in the garden, sweet peas should be planted very early in the spring or even during the previous late autumn. They will thus obtain an early start, and their roots will penetrate more deeply into the cool, moist soil before warm weather arrives, than if sown later. Moderately rich soil of a rather heavy nature generally gives best results; very rich soil tends to grow vine and leaf at the expense of flower; very poor ground is prone to produce small short-lived vines and little flowers which, however, are often pronouncedly fragrant. The
seeds should be scattered thinly in trenches about five inches deep and four or more inches broad. The distance between rows should be about three and one-half feet, the seed covered about one inch deep, and as the plants grow the earth should be drawn toward the vines until it forms a ridge two or three inches high. When the plants are well above the surface they should be provided with supports upon which to climb. Brush and poultry netting are gen erally employed. Throughout the season clean, shallow cultivation should be given and the flowers gathered daily. This last will consid erably extend the season since the formation of seed tends to a cessation of growth.
Several cloiely related species are cultivated for ornamental purposes but are less popular than the above. The best known are probably the following: The Tangier scarlet pea (Lathy rus ttngitanus), an annual herb which blossoms earlier than the sweet pea and should be planted separately because of its greater strength and its tendency to crowd out the former. The perennial or everlasting pea (L. latifolius), an odorless species with many-flowered clusters of diversely colored blossoms. It is popular for planting among rocks, in rough places and for screens, for which its rampant growth and har diness recommend it. L. rotundifolius and L. grandiflorus are also called everlasting and are cultivated to some extent, as are also L. tnari timus, the sea or seaside pea, and L. palustris, the marsh or wing-stemmed pea—the latter grown in damp Consult Hutchins, 'All About Sweet (1894), and 'Sweet Peas Up to Date' (Phila delphia 1897) ; Bulletins 111 and 127, Cornell Agricultural Experiment Station (Ithaca 1895, 1896) ; Bailey, 'Standard Cyclopedia of Horti culture' (New York 1916).