WHEN the sweet pea was first introduced into England from Sicily in 1699, the flowers were not much larger than those of a culinary pea, and there was only one colour — purple-maroon.
It was not till a hundred years later that the first record of any colour range was made, and then only five colours were mentioned — white, pink, carmine, mauve and purple.
No serious attempt was made to improve the sweet pea until about 1870, when Henry Eckford transformed a somewhat commonplace flower into the forerunner of the present sweet pea, but still there was only one popular type, known as Grandiflora.
The greatest advance in size and form came by way of a natural mutation in 1901 when the first waved, or frilled, form appeared. This was classified as the Spencer type. Since then development and progress have been gradual but quite appreciable, and a number of distinct forms and types have been found or developed and the size of the flower has more than doubled.
Now the colour range is very varied and the perfume abundant, despite the fallacy that sweethave almost lost their original scent.
Hardiness, constitutional strength and vigour are as good as they were 50 years ago, and the plants can be grown easily and successfully.
There is no generally accepted way of classifying sweet peas, but they can be divided into various groups according to height, time of flowering and number of flowers on each stem.
In the first group are the tall-growing types, intermediates and dwarfs.
In the second are the early-flowering, mid-season and late-flowering types.
The third group includes those that produce three, four or five flowers on a stem and the newer races such as Zvolanek’s Plentiflora, which give an average of five to eight flowers on a stem.
All modern types produce flowers of Spencer form, and among them are several early or semi-early types. The original early-flowering type was simply called Early Flowering, and was quickly found to be heat resistant and able to succeed in countries with hot, dry climates, where late-flowering Spencers, now the most popular type grown in Britain, were complete failures.
There have been several developments of the early-flowering group.
First came the Cuthbertson type, which had greater vigour, longer stems and bloomed for a slightly longer period than the original. This was followed by the Cuthbertson Floribundas, which possess the Multiflora tendency of producing more than four blooms per stem.
Then there are the somewhat similar Zvolanek Multiflora and Floribunda groups, the former the earlier flowering of the two. The most recent early- flowering races of Multiflora type are the Galaxy type and the Early Multiflora Gigantea type, both heat resistant and large flowered.
The group called Plentiflora developed by Zvolanek is among the late-flowering Multifloras.
Zvolanek’s Dwarf Pygmy and Burpees’ Dwarf Early are two new low-growing types. These grow 2 to 4 ft. high and produce normal-sized spikes.
There are only two modern forms of truly dwarf-growing types: the Cuthbertson Cupids (Colour Carpet), available in a mixture only, which make compact bushes 3 to 4 in. high and l ft. across, with flowers of normal size; and Little Sweetheart, available in mixture and in separate varieties, which produces compact, bush-like plants 8 to 12 in. in height and width, with flowers of almost normal size.
Sweet peas are ordinary hardywith a life span of 12 months or less.
Apart from the true dwarf types, they are of comparatively rapid growth both above and below ground. A single plant, given sufficient room to develop naturally without restriction, is capable of producing nearly 500 flower spikes.
Like most annual flowers, they prefer an open, sunny situation with good deep top-which is firm and well drained, but any soil which is capable of producing reasonable vegetable crops is almost certain to produce good sweet peas.
If each individual plant is given enough nutriment and enough room to develop properly it will sustain a lengthy flowering period.
If the plants are to be grown in ordinary, unrestricted fashion, prepare the ground as for any ordinary vegetable crop, digging one spit deep as early as possible, preferably in the autumn. Turn in a dressing of well-decayed animal manure, or good rotted, and work in bone meal, which is safe and always beneficial.
If the plants are to be grown by the cordon method, work the soil two spits deep — that is, double dig — mixing well-decayed animal manure or good fully-rotted compost well into the bottom spit and bone meal throughout both spits. Dried seaweed fertilizer is an excellent alternative as it disintegrates slowly, contains all the trace elements and can be used separately or with other feeding agents.
Double dig the sweet pea site all over rather than in strips, and leave the soil quite rough on top to obtain full benefit from winter frosts. Good drainage is essential.
If the soil is deficient in lime, sprinkle a dressing on the surface in mid-winter, for this helps to make heavy soil more workable. A top dressing of old soot at the rate of l bucket to 6 sq. yds. has much the same effect, but do not use both soot and lime in the same year.
In spring, a week or two before planting, lightly fork or rake the soil to give a fine surface.
Sweet pea seeds can be sown at any time from late September to mid-April depending on locality, but sowing in winter months should be done under glass.
In the south of the British Isles it is better to sow in pots or boxes in a cold frame from late September to mid-October. In the north sow in early spring, keeping the plants under glass, and later move them to a cold frame.
Open ground sowings can be made from the last week of February to mid-April, according to locality.
Sweet peas are hardy and resent being coddled. Keep thesturdy and hardy from the outset by giving them all the light and air possible and the mini-mum protection with glass.
When sowing in pots or boxes use an open porous compost, preferably sterilized, obtained from a nurseryman. Sow about 1/2. deep, allowing one or two seeds to a 3-in. pot and five to seven seeds to a 4-1/2 or 5-in. pot. When sowing in boxes, allow about 2 in. either way between seeds.
Make sure that the potting compost is reasonably moist when sowing and keep the frame lights on until the seedlings appear. Then, if the seeds were sown in the autumn, completely remove the lights and only replace them during very severe weather.
When the plants have made their second or third pair of leaves, pinch out the extreme part of the growing tips, as this will encourage the formation of strong basal side shoots, which are less likely to go blind than the original or seed growth.