The combination of fragrance, colorful clusters, and a climbing habit makes Sweet Peas a favorite among gardeners and non-gardeners, alike. Known for the more perfumed varieties, sweet peas are often described as smelling like a mix of honey and orange blossoms. Sweet peas are either a climbing or a bushy plant. Climber Perennial Blend can reach 4–10 feet and is well suited for trellises and arbors. Bushy sweet pea Cupid Pink is no taller than 18 inches and is perfect for container planting and garden borders. Blossoms also can be used for cut-flower displays.
Sweet peas’ native habitat is still debated to this day but most describe it as being native to Sicily. Monk and botanist, Father Francis Cupani, first described them around 1695. Four years later, after calling the flower a Sicilian wildflower, he sent some seeds to Dr. Robert Uvedale, a plant collector in England, and Dr. Casper Commelin, a botanist in Amsterdam. Over the next 200 years, interest in sweet peas grew and breeding increased. By 1900, there were over 300 varieties of sweet peas, and today, the number of sweet pea varieties is almost too many to count. An ambitious gardener can still to this day find the original ‘Cupani’ variety in some garden centers.
Just The Facts:
1. Nick the seed coat of sweet pea by rolling on rough grit sandpaper for faster germination.
2. Rotate your planting areas so sweet peas are only grown in the same space once every four years and do not grow in the same place where other legumes have been grown recently.
3. Sow 1" deep in rich, moist, fertile, and well-drained soil.
4. Most varieties require some support.
5. Sweet peas do best in sunny spots with late afternoon shade and good air circulation.
6. Keep roots cool by mulching and water regularly during the summer.
7. Remove old blossoms to encourage continuous blooming.
8. Sweet pea flowers self-pollinate while still in bud form.
9. Sweet peas (Lathyrus odoratus) are poisonous when eaten—especially the flowers and seeds.
10. Fragrance can be highly variable depending on weather and variety; choose varieties labeled as fragrant (Old Spice Blend).
Sweet peas can be a little tricky to germinate but are well worth the effort! They require scarification—a means of breaking through the hard outer covering to allow moisture to penetrate the seed. To achieve this, you can lightly roll them on a piece of rough sandpaper, so the seed coat gets nicked. Then sow at the recommended depth of one inch.
Sweet peas need cool soil temperatures to germinate. They will begin to sprout when soil temperatures are around 55° to 65°F. Be patient when growing from seed as they can take up to four weeks to germinate.
In cold winter climates, sow sweet peas in very early spring, usually about 4–6 weeks before your average last frost or as soon as you can work the soil. Don’t worry about sowing too soon because the plants can handle a light frost. If you are having a dry spring, keep the area moist, but not soggy, so the seeds remain viable until ready to sprout.
In warm climates, sow sweet peas August through December for mid-winter and early spring blooms. If you have a warm fall, it might be better to wait until a little later in the season to sow. If you have a lot of rain, or over-water the area, they may rot in the soil and not come up. Since birds, slugs, and snails covet the seedlings, you may want to cover the area with netting or screening to deter birds and put out slug/snail bait.
In cold, dry climates, some gardeners may choose to start the seeds indoors to have greater control over the environment and pests. When sowing indoors, start them 4–6 weeks before transplanting outside. Because sweet peas don't like to have their roots disturbed, sow in pulp pots. They need cool temperatures to germinate, so find a cool spot like a basement or unheated garage to start them. After they sprout, put them under grow lights or where they will get some sun but will still be fairly cool. Though they can handle light frost, harden them off slowly to avoid shock.
Special Care: Sweet Peas like deep, rich, fertile, and well-drained soil. Prepare beds 1 to 2 feet deep with lots of organic matter. Soil should be slightly alkaline or neutral. A slow release fertilizer is recommended at planting to ensure an even nutrient level throughout the growing season. If overfertilized, you will have lots of dark green leaves and few blooms. Keep roots cool by mulching and watering regularly during the season. Remove spent blossoms to increase bloom period.
The habit of sweet peas is most delightful and enhances most garden situations, from a mound type being no more than 18 inches (Cupid Pink) and well suited for containers and borders, to the perennial type (hardy to USDA zone 5) reaching a length of 10 feet. Many of the varieties are in the range of 4–7 feet and vining, making them perfect for arbors and trellises and behave well in both cottage and formal garden settings.
Long day, vining
Bouquet Blend, 5-6 ft.
Early Multiflora Blend, 5-6 ft.
High Scent, 5-6 ft.
Knee-High Blend, 2-3 ft.
Old Spice Blend, 5-6 ft.
Perennial Blend, 6-9 ft.
Perfume Delight, 5-6 ft.
Royal Blend, 5-6 ft.
Scented Streamers, 5-6 ft.
Singing the Blues, 5-6 ft.