Growing Sweet Peas, Annual Flower Information

LATHYRUS   Sweet Peas, Annual Flower Information

The Sweet Peas of our gardens delight us while they provoke us. We sincerely wish that they might bloom for a longer time, yet they are an unqualified joy when they are in flower.

Many thoughts arise in the minds of true Sweet Pea lovers. For Instance, Helen Milman, writes: “I think the Sweet Pea is a frivolous flower and leads a butterfly’s life, it wanders anywhere, and clings to anything, and has not any definite aim or ideal.” And Keats when lie thinks of Sweet Peas, writes:

“Here are Sweet Peas on tiptoe for a flight, With wings of gentle flush or delicate white, And taper fingers catching at all things To bind them all about with tiny wings.”

Another poet has written this jingle:

“Peas along the border, Peas upon the lawn,
Peas against an eastern wall to welcome in the dawn.Peas among the Roses, Peas behind the Pinks;
Peas to catch the western glow when evening sunlight sinks.
Peas upheld with Chestnut, Peas held up with Ash;
Peas sprawl on Hazel spray, Peas on Larchen brash.
Peas on stiff’ unyielding wire, Peas tied up with string;
Peas upon the trellis work were Rambler Roses swing.
Oh Merry, merry, merry, are the gay Sweet Peas;
Plant them when and how you will,
it’s certain they will please.”

Frankly, however, Sweet. Peas cannot be planted “when and how you will,” and it is to pointing the way to success in the “when and how” that the remainder
of this chat on Sweet Peas will be devoted.


There has been a gradual development of the Sweet Pea from the wild form in which the flowers were purple and small, to the modern race of ruffled sorts. The most popular today are those listed as Spencers, Waved and Orchid-flowering varieties. In these the flowers are large and frilled, three or four are borne on each stem and there is a wide range of exquisite colors. The older type, known as Grandiflora, includes the varieties that were seen before the year 1900. The early flowering varieties now listed are the types almost entirely grown in greenhouses today. These varieties bloom two weeks earlier and have the habit of flowering while rather small, after which they branch.


Sweet Peas delight in having their roots in cool, deep soil, and for this reason it is wise to prepare the soil in the Autumn, because in the early Spring it is hardly dry enough to work. Dig a trench at least two feet deep and a foot or more wide. Place several inches of manure in the bottom, and fill in with good soil so that the filled trench is rather arched at the top. The soil will settle somewhat and anyway, we do not want these rows to be below the soil level in early Spring. Furthermore, the rows when mounded, will dry out more quickly, and permit earlier planting.


When Sweet Peas are planted in the Fall, the flowers are produced earlier. This method is successful south of New York City on most soils, but farther north it is worth while only on well drained, sandy land. In localities where there are few alternate freezes and thaws, and the snow covers the soil most of the Winter, this method is highly recommended.

Sweet Pea trials at Cornell University, has experimented much with Autumn-sown plants and writes, that after preparing the trench, as just described,

The soil must be treaded in the trench so that it will not settle with the action of the Winter frosts. In fact, it is better to ridge the soil slightly over the trench to allow for possible settling, and for draining off surface water. In this ridge, there should be made a small furrow, two inches deep The seeds should be sown one inch apart in this furrow, and covered with two inches of soil. The row should be left slightly elevated when the planting is finished. The important point to keep in mind about Fall-planting Sweet Peas in the northern states, is to plant so late that the plants do not make any growth above ground until Spring. If the plants appear above ground they are killed by the Winter. Seeds that have only sprouted are not harmed. In central New York it is our experience that about November tenth is about the right time to sow, but, of course, this varies with the season.

After the ground freezes, a mulch of manure should be placed over the row, and if the snow remains all Winter, the conditions are very favorable. On the approach of bright, warm, sunny weather, examine the Sweet Peas, and, if they are found growing, remove the manure. It is a good plan to leave the straw portion between the rows, or near at hand for a while, so that it may be placed over the plants during sudden cold spells.

The Fall-sown Sweet Peas begin to grow earlier than it is usually possible to plant in Spring. They develop during the cool weather, make a better root system, and are stronger than plants from Spring-sown seed. The seeds of the standard varieties are so cheap that the Fall planting of Sweet Peas is well worth trying. Should the seed perish, the rows may be replanted in the Spring.


There is an old rule which says that Sweet Peas should be sown on Good Friday. This means simply that Sweet Peas may be sown as soon as the soil thaws in the early Spring, because the plants grow best during the cool, moist months.

It was formerly believed that Sweet Peas should be sown in shallow trenches six or eight inches deep, but it is now generally agreed that the row should be raked level and the seed sown only a half inch deep. It is best to sow thinly, meaning that only enough seed should be used so that the plants will stand six inches apart. Sweet Peas may also be sown in double rows a foot apart; this will allow space for the plants to develop and will at the same time produce a large quantity of bloom.


Sweet Peas maybe brought into bloom several weeks earlier and the plants will be better developed if started indoors, or in a hotbed. In a non active American Sweet Pea Society Bulletin:

Do not despair of raising good Sweet Peas if you are without a greenhouse, or even a coldframe; much may be accomplished by a little forethought and a little ingenuity. A flat, 14 inches long by 12 inches broad takes up but two square feet of room, and may be set in a house window. It is easily moved from place to place, holds about 100 plants in paper pots (which are four inches deep) and will give the plants plenty of room until they can be planted out. Now, these plants are enough to plant a single row 100 feet in length, or a double row 50 feet long, which is as much as many people can handle. Further, they will bloom longer and give superior flowers to any that may be planted closer; in fact, good sturdy plants set out in fairly rich soil will fill the space if planted two feet apart.

This outdoor planting must be done as early as possible, and the plants protected at night from frost. A good way to protect the plants in the row is to nail two boards together, so as to form an inverted V, and set it over the plants at night until danger from hard frost is past.


Many Sweet Pea seeds are very hard and germinate slowly, if at all. It has been found wise to give them some sort of treatment to insure prompt sprouting. Some soak the seeds in acid for a half hour, but the simplest method is to cut off a small piece of the seed coat on the side opposite the growing point. When such seeds are sown a half-inch deep in sand, they will germinate readily because they can soak up water easily. When so treated they germinate in a week and may then be placed in small pots to grow,

Light colored seeds which usually produce the white and paler tints and the mottled seeds (usually of the lavender, blue and mauve sorts), are apt to decay when the soil conditions are not favorable, It is the red, crimson and scarlet sorts that bear the hard seeds which it is well to germinate before sowing.


As soon as the seed is sown the gardener should consider the matter of supporting the plants. When the seedlings show a tendency to produce tendrils, they want to get hold of something and should not be allowed to sprawl over the soil. No matter what method of supporting is used, small, branchy twigs should be placed near the plants, and if the stems are slow in taking to the twigs tie some of them up.

Tall brush is the ideal material for supporting the plants because of its width, and the many twigs to which the plants can fasten themselves.

Wire netting may be used; it is neat and lasts for years. Some object to it because it is difficult to clean the tendrils from it in the Fall when rolling it up for the Winter.

Stakes, eight feet long, may be driven into the row and strong strings stretched between them. This is an inexpensive method, but as the strings stretch the effect often becomes unsightly. The lower strings should be placed five inches, and the higher ones farther apart.

A common English method and one worthy of trial in this country is to sow the seeds in circles several feet in diameter. Wire netting or a teepee effect made of stakes provides a support. The clump effect thus produced must be interesting.


If the soil is rich, little fertilizing is advisable, except a light dose of nitrate of soda, or dried blood when the stems begin to get short. In the case of nitrate of soda, we strongly advise dissolving it in water at the rate of a tablespoonful to a gallon.

When the soil is none too good at the start it will be advisable to give a dressing of bonemeal shortly after the plants are several inches tall. Scatter the bonemeal on both sides of the row so that the soil is white and rake it in. Some specialists believe that soot dusted over the soil every ten days brightens the color of the flowers.


Those who wish to keep their vines blooming as long as possible may try mulching the rows with decayed leaves or straw. This keeps the soil from drying and baking. Three inches of material should be used, but no more.

When a mulch is not used, the plants must be cultivated so that at no time shall the soil be baked at the surface.


Sweet Peas enjoy water and will thrive when given large amounts. A shallow trench hoed out six inches from the rows will be a convenient aid in watering.


Sweet Peas must be picked often and continuously if one wishes to fully enjoy them. Neglect in this particular soon causes them to go out of bloom. The best gardeners cut the flowers rather than pull them. Buy your Sweet Pea seed and do not try to save it, for it is better to have the flowers. It is well to cut some foliage with the flowers because this acts like a light pruning, causing the plants to branch. Foliage and young shoots are also useful when arranging the flowers.

Course Lesson 151 of the New York State College of Agriculture:

In order to have fine flowers and a long succession of bloom, it is infinitely more necessary to keep the seed pods rigorously picked off than it is to cultivate mulch, or water the plants. The latter operations go for naught unless the pods are picked off. The writer thoroughly believes that the importance of watering has been overemphasized and that too many amateurs prefer to use the hose rather than to pick pods; then they assert that the Sweet Pea is not what it used to be, that it has lost constitution. Of course, the more highly developed the variety, the less certain it is to bear up under neglect.

(Although from some of the older varieties in the College trials, no seed pods were picked, they continued blooming profusely, while the plants of the modern, waved sorts became in most cases, completely destitute of flowers under this treatment.)

The same holds true with regard to length of stem. Some plants of Countess Spencer were treated as above in order to note the effect, and for them the season was over early in August. The lesson is that if the grower does not intend to comply with the requirements of the improved types, it is better to grow the small-flowered, precocious varieties.


Plant lice are frequently troublesome on Sweet Peas. When this is the case spray the plants with a nicotine solution. Red spider is prevalent late in the season, and may be controlled by merely spraying with water daily. Its presence may be detected by a whitish appearance of the foliage and a webby covering.

This should not be confused with mildew, which appears as a white powdery growth on the foliage. As the mildew affects Sweet Peas only after their season of bloom is over, it is not usually serious. Mildew is controlled by dusting powdered sulfur upon the foliage. Other diseases affect Sweet Peas, but the methods for controlling them are not understood. Diseased plants should be pulled up and burned to prevent spreading the spores of the trouble.


(Ancient Greek name)

Growing Sweet Peas

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One Comment

    Mihka'el Caron


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    Mihkael Caron

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