Sweet Pea Flower Growing and Planting
In 1912 a Sweet Pea variety having a new and distinct flower form was exhibited. It had a frilled or waved standard petal (the large, top petal) and was raised by Silas Cole who was gardener to Earl Spencer of Althorp Park, England. The variety was named Countess Spencer and was the forerunner of a race that has given the form and perhaps much of the vigor to modern Sweet Peas.
Interest in America in Sweet Peas was greatly stimulated about 1886 when the Eckford varieties were introduced. Not all of the new varieties were "fixed," and those that were not did not breed true to type, but from them many new varieties that did breed true were raised in America. It was soon found that California has a superior climate for growing Sweet Peas for the purpose of seed production, and an important seed-raising industry has arisen there.
Several new types of Sweet Peas have been developed in California. One of the most important is Lathyrus odoratus variety nanellus, known as the Cupid, Dwarf or Bedding Sweet
Pea. It is a low, compact, nonclimbing plant and is available in a number of different flower colors.
Sweet Peas are classed in four main groups: the Giant Spencer or Ruffled varieties, which are most commonly used for garden purposes; the Multiflora varieties, which are remarkable for the number of flowers on each stem; the Cuthbertson varieties, which are a heat-resistant spring-flowering type; and the Early-flowering varieties, which are used for producing winter flowers in the greenhouse and for fall planting outdoors in regions of warm winters.
Ordinary Garden Culture
Soil Preparation. The Sweet Pea is primarily a cool-weather plant that requires an open, sunny location for its healthy growth. The best results are not easily obtainable except where the growing season is fairly cool. The soil should be deeply dug or plowed. A well-drained soil is most desirable, and it should be enriched with
liberal quantities of thoroughly decayed organic matter, such as rotted manure or rich compost, and an application of superphosphate. Finely ground limestone or a dressing of lime should be forked into the surface if the soil tends to be acid.
The preparation of the soil may be done in early spring, but it is better to complete it in the fall before planting, to ensure that the seedbed will be thoroughly settled before the seeds begin to sprout. The Sweet Pea prefers a rather firm, moderately well-packed soil.
Seeding. For ordinary garden use, seeds should be sown at the earliest possible time in spring when the soil can be worked, because, as with culinary Peas, root growth is more rapid before the higher temperatures of late spring and summer prevail.
Where winters are not excessively severe, November sowing may be practiced with advantage; although the seeds may not germinate until spring, they will be ready to respond as early as it is possible for them to grow. As soon as November-sown seeds are planted, cover them with 3-4 in. of salt-marsh hay or straw; do not remove this until late winter or spring, when severe freezing weather is over. Fall seeding is recommended only for specially favored locations. In many localities mild spells of weather during winter may incite too-early growth and the covering may cause decay.
Before sowing in spring (but not in fall) it is advisable to chip the outer shells of the seeds of all varieties except those with white or cream‑colored flowers, using a sharp pocket knife for the purpose. Chipping consists of removing a small piece of the seed coat so that moisture can enter more readily. The chip should be taken from the side away from the "eye" of the seed—that is, from the side away from where new growth develops.
In preparation for sowing, a trench or furrow 2-3 in. deep should be made; in the bottom of this the seeds are spaced 1-2 in. apart. Cover the seeds with a depth of soil equal to their own diameters. The soil that remains on each side of the trench after the seeds are covered will be filled in gradually by cultivation as the plants grow. When watering is done, the depression left at sowing time tends to keep water where it can soak down to the roots.
After the Plants Are Growing. As soon as the seedlings are above ground some form of support should be given. This may be done by inserting brushwood stakes or by erecting a fence of chicken wire, 5-6 ft. high, alongside the young plants.
The soil in which Sweet Peas grow must never become dry; weekly soakings with water are very essential in dry weather. One light dressing of a 5-10-5 or other regular, complete garden fertilizer (see Fertilizers), applied when the plants are half-grown, and immediately soaked in by watering heavily, is beneficial; but the best plan with Sweet Peas is to supply most of the plant food they need in organic form when the initial preparation of the soil is done. A 3-in.thick layer of finery manure or other mulch placed along each side of the row in late spring tends to maintain an even and relatively cool soil temperature, which is essential to the wellbeing of Sweet Peas.
It is very important that all flowers are cut off before they go to seed. This will notably lengthen the time that long-stemmed, good flowers will be produced by the plants.
Sweet Peas for Exhibition
For the production of the finest-quality Sweet Peas for exhibition or other purposes the cordon system of training is recommended. This involves considerable detailed work, but, if carried out faithfully, the results are plants with flower stems 15-18 in. long or longer, each carrying 4 or 5 large and perfect blooms.
Under the cordon system each vine is allowed to develop one stem only; no branching is permitted. To achieve this, all side shoots or laterals are pinched out while they are quite small, just as soon as they can be removed with the finger and thumb without damaging the main stem. The vines are tied or otherwise secured to tall bamboo stakes and all tendrils are picked off.
Plants trained as cordons may be raised from seeds sown directly outdoors in early spring, or in mild localities in fall. When this is done the seeds are spaced 2 in. apart in a single row and later are thinned so that the plants stand 6-8 in. apart. A better plan is to sow in pots or flats in a greenhouse or cold frame in fall and set the plants out in the garden in early spring.
Preparations for raising a crop of exhibition Sweet Peas should begin the fall previous to the summer in which they are to bloom. Both the starting of the seeds in pots or flats indoors and the initial making ready of the soil where they are later to be planted outdoors should be done in October or November; just before severe frost sets in is the ideal time.
Soil Preparation Outdoors. Good soil and a sunny, well-drained location are required. Here, open a trench or ditch 2 ft. wide and 18 in. deep; place the good soil equally on each side of the trench. If the subsoil is of poor quality, remove it and replace it with good-quality loam to a depth of 2-3 ft. If the undersoil is good, fork over the bottom of the trench to correct any packing that may have been caused by treading on it and, if possible, mix in some coarse compost or other organic material.
Fill back all good soil to within 3 in. of the surface, at the same time mixing in rotted manure, rich compost or other decayed organic matter (2 parts soil, 1 part organic matter) and 3 1/2 pounds of superphosphate to each 100 sq. ft. of surface. Fill the upper 3 in. of the trench, and to within 3 in. above regular ground level, with good topsoil into which bonemeal has been mixed at the rate of a good handful to every 6 sq. ft. of surface. If lime is needed, as it will be if the soil is acid, a good sprinkling should be raked into the surface.
Seeds and Seed Sowing Indoors. Seeds of the finest named varieties should be purchased from a reputable seedsman. The soil in which they are sown should be carefully prepared. It may consist of 3 or 4 parts good garden soil (loam), 1 part peat moss and 1 part sharp sand. If the loam is a heavy clay, greater proportions of peat and sand will be necessary. All the ingredients should be sifted through a 1/2-in. mesh and thoroughly mixed together.
Flats or pots (the 5-in. size is suitable) may be used as containers in which to sow the seeds. Fill these almost to their rims but leave room for 1/2 in. of coarse sand to be spread over the surface. Water the filled containers thoroughly and leave them for an hour or so to allow surplus moisture to drain away.
In each pot, scatter 10-12 seeds and cover them with 1/4 in. of sand. When sowing in flats, make drills 1/2 in. deep and 2 1/2 in. apart in the soil surface (using the edge of a 6-in. wooden label or similar equipment to do this). Space the seeds in the drills 1 in. apart and cover them with sand. A cool greenhouse (40-50 degrees night temperature) or protected cold frame is an ideal place to keep the pots or flats after sowing.
When germination takes place, which occurs in 9-12 days, the seedlings must have all possible light and a cool, airy atmosphere. Watering must receive careful attention. As soon as the seedlings have formed their first leaves they may be transplanted singly to 2 1/2-in. pots containing a soil similar to that used for sowing.
Keep the newly potted plants in a location in the greenhouse or cold frame where it is cool and airy and where there is good light. They should not, of course, be subjected to freezing but night temperatures of more than 50 degrees must be avoided. In 4 to 5 weeks they will be ready to repot into 4-in. pots. Use a soil similar to that used earlier but with a 6-in. potful of sheep manure and a 2-in. potful of superphosphate added to each bushel of the mixture and mixed in thoroughly.
After the last potting, the plants may be placed in a cold frame, except where winters are exceptionally severe. During mild weather the frame sash should be taken off. Retain all growth that develops until the pots are filled with roots, after which time most varieties may be pruned to two vines or stems to each plant.
Orange-pink and orange-scarlet varieties are not such strong growers as the others and so should be pruned to one vine or stem to each plant. At this time they should be given supports of light brushwood.
Planting. This is done after the plants have been thoroughly hardened by exposure to the cold winds of spring. At that season they tolerate light frost. The time of planting is from the middle of March to the middle of April, depending on the locality; the important point is to plant as early as the ground is workable and danger of really severe frost has passed.
Make sure that the plants are watered well a few hours before planting. When planting, turn the pot upside down and give its edge a sharp tap with the planting trowel to release the plant from the pot. Dig a hole big enough for the roots to be spread out after shaking the old soil from them. Fill in fresh soil around the roots and pack it moderately firmly. If the plants need additional support, insert some brushwood stakes near them. This will protect the plants from wind, and new tendrils that develop will have something to which they can cling.
Staking. A substantial framework is necessary to hold the stakes for cordon-trained Sweet Peas. The strain on the supports during high winds will be enormous after the vines have grown tall. It is common to allow them to grow 8-9 ft. high. A strong post 10-12 ft. long should be inserted 3 ft. deep at each end of the row. Each of these should be strengthened by a guy wire attached to its top and to a strong stake driven into the ground beyond the end of the row. If the row is long it may be necessary to insert additional posts at intermediate points. When the posts are in position two wires are stretched from post to post, one 2 ft. from the ground, the other at a height of 5 ft. To these wires the stakes are tied 6-8 in. apart. While any straight stake is suitable, stout bamboo canes are most serviceable.
Pruning, Disbudding and Tying. Following planting, growth will be slow for two or three weeks and no pruning should be done until the plants are growing well again and are at least 18 in. high. When surplus side growth is left undisturbed, root growth develops more quickly than if all but the "cordon" or leading growth is pruned away. When fast growth is really obvious, all side growths, flower buds, and tendrils should be cut away and the leading growth tied to the stake. This must be done every 3-4 days.
Flowers should not be allowed to develop until the plants are 4-5 ft. high. This will be towards the end of May in most localities. Up to this time the surface soil should be kept loose and free from weeds with a hoe or cultivator. Periodic watering is likely to be necessary in most regions from the end of April onwards. Towards the end of May a mulch of litter, compost or other suitable material should be applied. Fresh manure should be used sparsely, if at all, because of danger of damage to the plants. The same caution should prevail in using chemical fertilizers. Slight overdoses may cause the flower buds to drop.
Shading. Although the Sweet Pea requires good light, some scarletand orange-flowered varieties retain their lustre better when the flowers are shaded from strong sunshine with cheesecloth.
Qualities for Exhibition. The judge of Sweet Peas looks for a straight stem that holds up the flowers. It should be 15-18 in. long but not excessively thick. There should be 4 or 5 flowers to a stem, evenly and pleasingly arranged, not separated too far from each other. The size of each should be approximately 3 1/2 in. across the standard (upper petal). They should be fresh, without blemish, of good clear color, and thickness of the petal should be ample to avoid an appearance of flimsiness. Flowers for exhibition should be cut late in the evening preceding the show, placed in containers filled with water and kept in a cool room overnight.
Seeds of Early Flowering or Cuthbertson varieties of Sweet Peas may be sown late in August to produce flowers at Christmas and on into late winter. The best plan is to sow them where they are to grow and bloom rather than to transplant them. A solid bed (one that is not elevated) may be used for sowing, or boxes 1 ft. wide, 1 ft. deep and of any convenient length, or 8-10-in. pots. Rich well-drained soil gives best results. The greenhouse roof must not be shaded, because Sweet Peas require all possible sunshine. A fall and winter night temperature of 50 degrees F. is ideal. During the daytime a 5or 10-degree rise is permitted or even a few degrees more on very sunny days.
Giant Spencer or Ruffled varieties of Sweet Peas are good for producing spring flowers if they are sown in September. Potting, planting, disbudding, etc., is similar to that recommended for outdoor exhibition culture. The plants should be set in the beds, boxes or pots in which they are to bloom in November. This crop may be used to follow Chrysanthemums.
For greenhouse-grown Sweet Peas it is best to use new soil for each crop. Supports usually consist of thin wires nailed 8 in. apart to one end of the bench, and stretched along the top of the soil, tightened and nailed to the opposite end of the bench. A framework of metal or wood 6 ft. high is erected at each end of the bench. To the top of this wires parallel to the rows of wire at the bottom are stretched. Strings attached to the bottom wires at 8-in. intervals are stretched tautly and tied to the top wire immediately above. As the plants grow they are twisted around these strings and this gives sufficient support. These cordon Sweet Peas grow quickly and, when they reach the tops of the strings, the strings may be cut, the vines laid along the ground and twisted around a new string 4 ft. away. They will then start to climb up the new string and will supply good flowers until late in April.