SWEET PEA

Lathyrus odoratus. Hardy climbing annual



The history of the Sweet Pea can be traced back for more than two

hundred years; and it is almost as fascinating as an exhibition of the

flowers. Recent improvements in this highly popular subject include an

amazing diversity of colours, a marked increase in the number of flowers

on each stem, and an extraordinary enlargement in their size. A modern

list may run into hundreds, but those who grow every known variety find

that there are many close resemblances, arising no doubt from

simultaneous introductions by hybridists who have experimented on

similar lines. Enthusiastic growers of Sweet Peas are no longer content

with a limited number of named varieties, for it is obvious that in

competitions where fifty or a hundred bunches have to be staged for

certain prizes, a large and representative collection must be grown. For

general garden decoration, however, and to provide sprays for the

adornment of homes, the Giant-flowered class, offered under colours

only, will continue to be extremely popular.



The change in character and the increased usefulness of Sweet Peas have

necessitated a revolution in the methods of culture. The freer growth

and more robust habit demand greater space than was formerly allowed.

Instead of crowded rows of attenuated plants, producing a meagre return

of small flowers, poor in colour, it is now the practice to prepare the

ground by deep trenching and liberal manuring, and to give every plant

ample space for full development both in rows and in clumps. In the

ensuing paragraphs we outline the cultural routine which should be

followed as nearly as possible by those who desire to insure a

long-continued supply of the very finest flowers. But where

circumstances do not permit of these recommendations being adopted in

full, the details may be modified according to the materials at command

and the requirements of the cultivator.



It is usual to commence the preparation of the ground in autumn.

Trenching is of paramount importance, for the roots of the Sweet Pea

require a considerable depth of good soil in which to ramify for the

support of robust healthy plants capable of producing handsome flowers

over a long season. Where the surface soil is shallow, care must be

exercised to avoid bringing uncultivated subsoil to the top, and it is

well worth incurring a little extra trouble to provide a sufficient

depth of fertile material for full root development. Therefore dig out a

wide trench and place the good top soil on one side. Then remove and

discard the subsoil to a depth of twelve inches and, after breaking up

the bottom of the trench with a fork or pickaxe, replace with an equal

quantity of decayed manure, leaves, old potting soil or any other

suitable stuff that may be on hand. Finally return the top soil to its

original position.



The use of manure needs discrimination, and in fixing the quantity, as

well as in selecting the most suitable kinds, due consideration must be

given to the character of the soil. For light land, four barrow-loads of

well-rotted farmyard manure per square pole will make an excellent

dressing, but a rather smaller amount will suffice for heavy ground. In

place of farmyard manure an unlimited quantity of leaf-soil, if

obtainable, may be used, and it is also a good plan to dig in any

available green refuse. Garden ground which for some years previously

has been kept in a state of high cultivation by the liberal use of

natural manure will not, as a rule, need further help in this direction,

but it should receive a good dressing of lime. Indeed, any soil in which

Sweet Peas are to be grown should contain not less than two per cent. of

lime. The employment of artificial, as well as organic, manures is

essential in any first-class scheme of cultivation. But here a word of

warning is necessary. Nitrogenous manures in any form are harmful to the

plant when applied in large quantities, and are liable to predispose it

to disease, except on extreme types of sandy soil. Heavy ground should

be dressed with seven pounds of basic slag in autumn and two pounds of

sulphate of potash in spring. On light soils apply in spring four pounds

of superphosphate of lime and two pounds of sulphate of potash. The

quantities stated in each case are sufficient for a square pole of

ground. Wood ashes (in a dry state) are also of great value, and these

should be raked in a little in advance of planting out.



The special preparation of the soil just described entails the raising

of plants in pots or boxes in readiness for transfer to the open as

early as weather permits in spring. The finest flowers are undoubtedly

obtained from an autumn sowing, and about the middle of September may be

regarded as the best period for putting in the seed. This early

commencement possesses the advantage of allowing ample time for the

development of sturdy, well-rooted plants, which will not only bloom in

advance of those sown in spring but will remain in flower for an

unusually long period. Sow in light porous soil, and either three-inch

pots, pans or boxes may be used. Place in a cold frame and keep the

lights down until the seeds have germinated, but afterwards the frame

should never be closed except during severe weather. There must be no

misunderstanding on the question of air-giving. The Sweet Pea is almost

hardy, and robust healthy seedlings, grown as nearly as possible under

natural conditions, are wanted. Therefore to subject the plant to

artificial heat will only defeat the object in view. A current of air

should be admitted to the frame day and night, and the lights may be

entirely removed on all favourable occasions. But the seedlings will

need protection from excessive moisture, for if too wet at the roots

they are liable to injury from frost. When four pairs of leaves are

formed, stop each plant once, and after a little further progress has

been made transplant singly into three-inch pots. Keep the pots in the

frame, giving only such protection from hard weather as may be

absolutely necessary, and plant out on the first suitable opportunity.

In the South transplanting may be possible late in February or at the

opening of March, but a month later will be safer in districts north of

the Trent.



Those who for any reason do not find it convenient to sow in autumn may

start the seed early in the year--from mid-January onwards, according to

the district. The general principles described in the preceding

paragraph apply equally to spring sowings, but it may be well to say

that there must be no attempt to hasten growth by the application of a

high temperature. A frame will afford all the protection necessary, and

even a box covered with glass and placed in a sheltered spot will be

found serviceable for raising seedlings.



Before planting out, the top soil of the ground prepared in autumn must

be well worked and made friable. The disposition of the plants, and the

method adopted for staking them, will, to a great extent, depend on the

precise purpose for which the flowers are required. For garden

decoration single rows answer well, and the plants should be spaced one

foot apart. Or, if preferred, put out in clumps of three to five plants,

allowing a diameter of from nine to fifteen inches. Carefully remove the

plants from the pots or boxes in which they were raised, disentangle the

roots and shake them quite free from soil. Make a hole of the necessary

depth, and allow the roots to descend into the ground to their full

extent, which may be as much as two feet in the case of well-grown

specimens from autumn-sown seed. Give support immediately with

well-branched twigs, and it is important that the plants be kept

perfectly upright. Finally stake with bushy hazel sticks eight to ten

feet in height, or taller still where the ground has been generously

prepared.



Long-stemmed flowers free from blemish are essential for show work and

for the highest forms of house decoration, and to insure an adequate

supply over an extended period the following method, which is adopted by

some of the most successful exhibitors, is strongly to be recommended.

The plants are put out in double rows one foot apart, and spaced a foot

apart in the lines. Each plant should carry two shoots only, both of

which must be provided with a rod of bamboo, ash, or hazel, ten to

twelve feet in length. For this double cordon system the rods will stand

six inches apart in the rows, and it is desirable to make them secure

against damage from high winds. Insert a stout pole at each end of the

row, and about seven feet from the ground-level fix to each pole a

substantial wooden crosspiece a little more than a foot in length. From

these cross-pieces tightly stretch strands of wire, to which securely

tie the rods. As growth develops commence disbudding promptly, regularly

remove all laterals and tendrils, and tie each cordon to its supporting

rod with raffia as often as may be necessary.



After transfer to the open ground the plants must never be allowed to

become dry at the roots. Keep the hoe going between the rows, especially

after the soil has been beaten down by rain.



The blooming period can be prolonged by the simple expedient of daily

removing the dead or faded flowers. The ripening of only a few seed-pods

speedily puts a stop to flowering.



In the open ground seed may be sown in spring from February to May, and

successional sowings at intervals of a fortnight will extend the supply

of flowers far into autumnal days. Even where a few clumps only can be

grown it is unwise to depend on a single sowing. Autumn sowings outdoors

are often made in September or October where a warm soil and favourable

situation can be insured.



Sweet Peas have two principal foes, the slug and the sparrow. Against

the former the usual precautions, such as ashes, old soot, lime, and

various traps, are available; and the latter must by some means be

prevented from doing mischief. After the buds show through the soil, it

is generally too late for the adoption of remedies. Nearly all the heads

will be found nipped off and laid ready for inspection. One could almost

forgive the marauders were food the object, but the birds appear to

commit havoc from pure wantonness, and whole rows are sometimes

destroyed in a single morning.



Early sprays are so much prized that the practice of flowering Sweet

Peas in pots under glass is yearly increasing, and for this purpose seed

must be sown in August or September; the plants to be kept slowly moving

during the dark days. In February the growth will be more rapid, but it

is important to give the plants the hardiest possible treatment. In

April, if properly managed, there will be a brilliant display.



The winter-flowering race blooms freely at a still earlier period,

although the plants are less vigorous than other varieties.