Sweet peas are beautiful annual plants with a sweet smell, sentimental appeal and long time of bloom.
They probably showed off their vivid blossoms in Grandmother’s garden and they deserve a place in the landscape now as much as they did a century ago. The blossoms, growing in large clusters make people think of colorful butterflies fluttering above the vines. Those colors include pinks, crimson reds, navy blues, pastel lavenders and the purest whites. They may be solid colored, bicolored or streaked or flaked colors.
As a bonus, those blooms are longlasting as cut flowers.
In North America, gardeners can enjoy these bloomers from early spring onward. The seeds should be planted in early spring, so understand that you may not get as long a bloom period by planting them now. Extend their bloom time by protecting them from intense afternoon heat and mulch well.
In the past century these flowers have been popular in the United States, but gardeners and botanists have found an interest in them for centuries. The first written record appeared in the 1695 writings of a Franciscan monk in Sicily. He passed seeds along to a Dutch botanist, Dr. Casper Commelin, and probably also to a Dr. Robert Uvedale in Middlesex England. Cupani gets credit for the variety he discovered — a bicolor with a purple upper petal and deep blue winged petals. It is available to gardeners today still under the name Cupani!
Until the middle of the 1800s, only six colors of sweet peas were available in Europe, but by the end of the 19th century, Henry Eckford of England introduced grandifloras. Grandifloras were larger, offered more color choices and were generally prettier than their predecessors.
The changes continued in 1901 when the head gardener to the Earl of Spencer found a mutation in his garden and named it Spencers. This flower had a ruffled upper petal and longer lower petals creating a bigger bloom and the plant produced more flowers per stem. They became known as multifloras. They were late flowering varieties, which did not matter when grown in the cool English climate.
American seed companies have contributed to yet more variations including three from the early 20th century that are still popular.
They include the long vined “Royal Family” colors, shorter ‘Knee-Hi Mix’ varieties and very compact ‘Little Sweetheart Mix.’ Those who like container gardens will enjoy the compact sweet peas such as the ‘Cupid’ varieties which grow in window boxes, hanging baskets and containers.
Sweet pea fragrance may vary due to weather conditions, time of day, temperatures and the age of the flower. They also vary from plant to plant. The name sweet pea refers only to fragrance.
Although garden peas, edible podded peas and snow peas are edible, sweet peas (Lathyrus odoratus) are poisonous — especially the flowers and seeds.
Choose your garden spot, then determine which peas to plant there. They can be categorized by growth habit, flower form, fragrance or day length response.
• Climbing habit — Plants produce tendrils which wind around a support and may grow six to 10 feet or may be compact with plants reaching from eight to 24 inches tall and needing no support.
• Flower forms — Flower forms may be single, double or semi-double and may be fragrant. If the scent is important to you, look for packets of seeds labeled fragrant.
Many plants initiate buds or flowers under certain day length and sweet peas are no exception.
Look for long-day flowering varieties for our area because they produce blooms as the day length increases.
Plant growth and care
• Seeding — Choose a spot with full to partial sun and deep, rich, loamy, moist but well-drained soil. Add plenty of organic matter. They perform best when started during periods of cooler temperatures. In our area, plant sweet peas in early spring. They can withstand some frost without much damage to plants and will perform longer in areas of the county with cool summer nights.
Sweet peas need about 50 days of cool temperatures (under 60 degrees F) to bloom gloriously in your garden. Sow sweet peas outdoors as soon as the soil can be worked — up to six weeks before the last frost date. Sweet pea seed will germinate in soil at temperatures of 55 to 65 degrees F.
Seed coats on sweet peas are hard and soaking in water does not hasten germination. Try nicking the seed coat with a nail clipper or file to hasten water absorption and germination. If planting outside, plant about two inches deep in holes four to six inches apart. Water thoroughly and keep the soil moist until the seeds sprout — about 10 to 21 days. Sow seeds each week over several weeks beginning in early spring to further extend their bloom time.
It is probably a little late to direct seed for this year, although soils are probably still cool enough. If summer jumps in abruptly as it often does, and nights are not chilly, they will not bloom for very long.
• Transplants — You may find sweet pea transplants at some specialty nurseries or garden centers. They need special care not to disturb roots when transplanting so those in peat pots are a better choice and the bigger the pot, the better.
Snip off flowers or buds just before you plant to allow the plant to send its energy to the roots in the beginning to strengthen them. You will sacrifice early blooms but will ultimately get bigger plants with abundant large flowers.
Plant into prepared garden soil or a container. If you grow long vine sweet peas, place stakes or supports in the ground before you place the transplant so you do not damage the roots. Lightly firm the soil around it and water.
After a week, add mulch being sure to keep it at least an inch away from the stem of the plant until plants are well established. Otherwise you could smother the stem or encourage insects, pests and diseases.
• Care — Sweet peas are leguminous plants and do not need much nitrogen fertilizer. Too much will force lots of green growth and few flowers. Try a balanced 20-20-20 slow release fertilizer blended into the soil at planting time for the initial plant development.
Either cut the blooms regularly or deadhead the plant when the flowers fade. Removing spent blooms will ensure more blooms.
Rotate planting areas so that the sweet peas are grown in the same space once every four years.
Don’t grow sweet peas where other legumes are growing or grew last year. Legumes include garden peas, beans of all types, peanuts and clover.
• Container culture — Use dwarf varieties such as Cupid for container gardens. These are wellsuited to hanging baskets, pots, urns, window boxes and so on. There are many dwarf sweet pea types available from mail order catalogs or in seed packets purchased at stores.
Don’t overlook climbing sweet peas as container plants to grow up a support. Plant the seeds in a circle a couple of inches apart an inch from the rim of the pot. In the limited space of a container, it is easiest to plant the support and then sow the seeds around it. Consider tomato cages as supports in large containers. You can plant them indoors and set them out in early spring.
• Cut flowers — Start cutting flowers for indoor bouquets as they appear. Stems look full when you first arrange them and the remaining buds will open as the first blooms fade. Remove leaves that are below water level in the vase. A bouquet of sweet peas can easily last a week indoors if you cut off 1/4 to 1/2 inch at the base of each stem and change the water daily.
Tip for the Week:
• Cut lawns to three inches for healthy growth.