SWEET PEA 



SWEET PEA 



3289 



will usually destroy them. Plants that are frequently 

 syringed with cold water are seldom infested with 

 insects. 



Fungous pests. 



The most prevalent fungous pest affecting sweet peas 

 under glass appears to be Thielaria basicola, or root- 

 rot. Infected plants have little or no root-system, due 

 to the fact that new roots are constantly destroyed. 

 The leaflets often turn yellow with white edges, finally 

 dying and falling to the ground. Sometimes one por- 

 tion of the plant may be dry and dead while the 

 remainder is green, although it does not grow or pro- 

 duce flowers. In fact, it is sometimes a mystery how a 

 diseased plant can continue to live with its very limited 

 root-system. There are some other root-rot organisms, 

 but their action is similar and the method of control is 

 the same for all the removal of infected soil or steri- 

 lizing it. 



The powdery mildew attacks greenhouse sweet peas 

 at any stage of growth if the proper temperature is 

 not maintained. The application of sulfur to the heat- 

 ing-pipes will check this disease. Care must be taken 

 not to use the sulfur too strong or the flowers will be 

 injured. Outdoor mildew usually does not appear until 

 late in the season when the plants are failing. 



Sweet peas grown in the open garden may be at- 

 tacked by the root-rots above mentioned or by anthrac- 

 nose and mosaic diseases, which may be serious. The 

 former attacks the leaves, stems, flowers, and pods, 

 but is most frequently found on the latter which are 

 attacked at any stage of development. The affected 

 parts wilt and die. The disease can be carried over 

 winter upon the seeds. The prompt destruction of 

 infected plants, as well as the burning of all old vines 

 in the fall and the use of clean seed or treating the seed 

 before sowing, will do much to lessen the danger from 

 this disease. The mosaic disease, which may be allied 

 to or identical with the trouble known as streak in 

 England, is a rather baffling disease to the growers. 

 It is distinguished by a yellow mottling of the leaves 

 and stems of the plant. This is often accompanied 

 by a curling of the leaves. The plants become stunted 

 in growth and cease flowering if they have reached the 

 flowering stage. It is a disputed point whether it is a 

 bacterial disease or not, but it seems certain that the 

 trouble is transmissible by the feeding of aphides. No 

 remedy is known except the obvious one of keeping 

 insects in check and destroying affected plants by fire. 



The dropping of the young flower-buds either in the 

 open or under glass is usually due to physiological con- 

 ditions. Low temperature, lack or excess of plant-food, 

 too much nitrogenous fertilizer, lack or excess of water 

 are among the causes of this trouble. A. C. BEAL. 



Growing sweet pea seed in California. 



Up to about the year 1885, most of the sweet pea 

 seed was grown in England, France, and Germany, 

 and imported to this country; at that time the first 

 attempt was made to grow the seed in California. This 

 resulted in almost immediate success, and in 1900 

 more than 600 acres were devoted to the growing 

 of the crop. Most of the sweet peas grown at this 

 time were of the Grandiflora type and yielded an 

 average of 1,100 pounds to the acre, sometimes in a 

 good year even as much as 2,200 pounds. With the 

 introduction of the Countess Spencer type of sweet 

 pea, about 1904, however, the waved forms supplanted 

 the Grandiflora type, the larger part of the acreage 

 being now devoted to the Spencer type. Approxi- 

 mately 2,500 acres are now planted to the sweet pea. 



The original Countess Spencer sweet pea was of a 

 shell-pink color, but it was not fixed and many color 

 sports were produced. At present there are about 150 

 distinct varieties of the Spencer type under about 460 



different names, resulting from different growers finding 

 the same sports, or from varieties which were not 

 improvements on existing varieties of the same colors. 

 The yield of seed to the acre of the Spencer type is 

 much less than from the Grandiflpra type, only about 

 250 pounds to the acre being obtained. This difference 

 in yield is due to the structure of the flowers: in the 

 Grandiflora type the keel is closed, not allowing the 

 pollen to escape so that each variety must pollinate 

 itself, and the varieties can be grown close together and 

 yet remain true to color and t ype ; in the Spencer type, 

 however, the keel is open, allowing the pollen to be 

 blown out, and, as a consequence, about 75 per cent 

 of the flowers do not set seed; also the plants must be 

 set far apart in order to keep them true to color and 

 type. 



A cross was made between the Spencer sweet pea 

 and the winter-flowering sweet pea, resulting in the 

 winter orchid-flowering sweet pea. This is a shyer 

 seeder than the Spencer, yielding only about seventy- 

 five pounds to the acre. The flowers resemble the 

 summer Spencer except that the growth is dwarf and 

 the foliage more pointed. If sown in August under 

 glass in the eastern states, they will bloom from 

 November until late in spring. If sown outdoors, they 

 will bloom three to four weeks earlier than the summer 

 type, just before the extreme hot weather. 



There are four types of sweet pea now grown in 

 California: the summer Grandiflora, the winter Grandi- 

 flora, both of these being grown only on a small scale; 

 the summer Spencer, and the winter orchid-flowering. 

 In addition, the Cupid, which grows 5 to 6 inches high, 

 is occasionally grown, only about 30 acres a season 

 being devoted to it. 



The raising of the sweet pea seed is usually on a large 

 scale. Large tracts of land are plowed in autumn about 

 10 inches deep, either by horse-power or large tractors, 

 before the beginning of the rainy season. The field is 

 then carefully disced and pulverized and left to settle. 

 If the rainy season begins as early as October, the 

 fields shoulo! be harrowed again after the rain and the 

 seeds planted. However, if the rains do not come until 

 late, the seed must be sown in the dry soil, although 

 they will not germinate so evenly. The most successful 

 seeding is done between November and January. The 

 seed is sown mostly by four- or two- row horse planters, 

 being planted 30 inches apart and 3 inches apart in 

 the rows, and 2 inches deep. Between each named 

 variety, at least 10 feet must be left to prevent crossing. 



After the seed is planted, the field must be[_kept in 

 good condition by hoeing. After each ram the ground 

 between the rows must be broken up. As soon as the 

 plants are up, a horse cultivator may be used which 

 breaks the crust 2 or 3 inches deep and 3 to 4 inches 

 from the plants; but hand labor must be used to cul- 

 tivate nearer the plants. This must be done after 

 each heavy rain, sometimes five times being necessary. 

 Irrigation is seldom practised, as 10 inches rainfall ig 

 sufficient for a good crop of sweet peas. 



By the latter part of March and April the winter or 

 early sweet pea will be in flower, and the summer or 

 late sweet pea begins to bloom in May. Now must 

 begin the process of thinning. No matter how carefully 

 the seeds have been selected, there will be some 

 "rogues" and these must all be removed. The best 

 among these may be tagged and kept for stock seed to 

 grow later on. All novelties and the stock seed for the 

 next year are usually planted and taken care of by 

 hand. 



After the thinning has been done, the plants are left 

 to themselves, no supports being given them, until the 

 seed is ripe. These seeds are not evenly ripened and 

 the cutting must be done when the larger part of the 

 seed is ready to be harvested. The cutting is per- 

 formed by a specially constructed ripper drawn by two 

 horses and cutting two rows at once. As soon as cut, 



