Gardeners Chronicle & New Horticulturist p. 355 (Nov 23, 1907)
WINTER-FLOWERING SWEET PEAS

"ABOUT 25 years ago," writes Mr. Anton C. Svolanek in the Weekly Florists' Review (America), "I made my first experiments in raising Sweet Peas in winter under glass. I tried all varieties which were at that time obtainable, but could never raise a plant which would give flowers before the latter part of the month of April. After several years of such experiments, I came to the conclusion that it was impossible to get Sweet Peas earlier than the time mentioned from the present existing varieties, so I started cross-fertilisation with other species of Lathyrus, but, for the first few years, without success. I obtained several new varieties, a few of which were double-flowered, but not one that was free-flowering, until I made a cross with the European Vetch, largely grown by farmers in Central Europe as green fodder. In October, 1891, I sowed some of this seed gathered from plants crossed with the Vetch, and on the following January 1, 1892, I was surprised to find two little plants, each with one open flower and several buds. The flowers were very small, colour reddish-pink, and not of much value, the plants growing only to a height of 24 inches under glass. But I was satisfied with this for a start, and increased the stock of seed all that I possibly could. I crossed and re-crossed each year, and each new cross showed improvement over the previous one in size of flower, colour, length of stem, and in the plant itself. The first seedling of value which appeared was obtained from Blanche Ferry: it came of the same colour, but the plant was only 20 inches high, under glass, and bore only ten single flowers. But after much crossing and re-crossing with the parent variety, I secured fine, long-stemmed, large flowers, plants over 6 feet high, which were covered with masses of bloom all winter. The first variety was named Christmas Pink. I now have a large number of varieties in all existing colours. All these varieties, when grown under glass, begin to" bloom when 3 to 4 feet high, and continue flowering all winter, sometimes until June."

Mr. Svolanek states that he finds it necessary each year to grow his stock seed under glass, as in the beginning, because the varieties quickly revert to the ordinary type of spring-flowering Peas if not so handled. Last year he secured 40 pounds of stock seed in his greenhouses. This seed was sown in the Santa Clara Valley, California, and in a little valley in Austria, about ten miles distant from Trieste, where, for an area of about two miles in width and ten miles long, the climate resembles that of Santa Clare, but is rather more favourable for the Sweet Pea, owing to there being scarcely any rain during the floweriug season.

Sweet Peas for Profit p. 93 (1914) by John Harrison Dick