Sweet peas are one of the few annual flowers with enduring appeal and rural charm. They appear to be the exact opposite of our hurried life as they twine languidly around a rustic trellis. Sweet peas are fantastic flowers for gardens and bouquets thanks to their alluring scent. For information on how to plant and care for sweet peas, read our Sweet Pea Growing Guide!
About Sweet Peas
The sour pea Lathyrus odoratus is an annual flower that looks great twining on a trellis or arch, growing in a cutting garden, border garden, or woods. Today, a wide variety of hues, from pearly white to ice cream pastels to ritzy magentas and inky purples, are available for the blooms.
Only their honey and orange blossom fragrance matches their delicate winged flowers. Their appeal has been ensured by the combination of their exquisite aroma and their capacity to generate a large number of flowers for the house over an extended time of cutting.
One of the keys to cultivating sweet peas is to sow them early. Sweet peas are incredibly tough, despite the way they appear fragile. Plant them in very late winter or early spring in USDA Hardiness Zone 7 or colder, as soon as the soil is dry enough to work with. (Don’t plant seeds after the last frost.
When Dr. Robert Uvedale, a teacher from Enfield, Middlesex, received seeds of this exceedingly fragrant annual in 1699 from a Sicilian monk named Francis Cupani, he brought the first sweet peas to Britain. In North America, they gained enormous popularity as garden plants and cut flowers. By the late 1800s, producers in California, especially W. Atlee Burpee, were exporting trainloads of sweet peas across the nation and creating numerous new varieties.
Some people liken the process of producing sweet peas to that of preparing pie dough. Some individuals are gifted, while others are not. This plant sprouts from large, manageable seeds that resemble peas. They are still rather challenging since they take a while to germinate. It’s worthwhile to experiment with various seeds every year.
When to Plant Sweet Peas
- Sweet peas should be planted as soon as the soil is dry enough to work in very late winter or early spring in most places where frosts occur frequently (Zone 7 and colder). (Start sowing before the last frost! Most certainly, it will be too late.)
- Plant sweet peas in the late fall (November) if you garden in a region with a mild winter climate (Zones 8, 9, or 10), so they can grow and blossom in the late winter and early spring. Six weeks before you plant the seeds, dig a trench and fill it with compost or well-rotted manure to obtain the greatest show. Sweet peas are gregarious plants that require a lot of nutrient-rich materials to flourish.
Sowing Sweet Peas Indoors
- Start sweet peas inside in a seed tray to get a head start on the season in the coldest regions of the nation. Sweet peas can withstand light frosts, so plant out as soon as the soil can be worked in early spring, around 6 to 7 weeks before the last date for frost.
- The seeds’ outer layer is softened and helped to germinate by soaking them overnight. Using a nail file to lightly score the outer shell can also be beneficial.
- 2 seeds to a module is fine to sow the seeds, but keep in mind that their lengthy roots have a propensity to tangle and can make separation challenging. Sow the seeds around half an inch deep in each cell of a seed tray.
- Scoop them out gently after they start to sprout their first pea-like leaves and place them in a larger container to harden off. One of the most reputable growers of sweet peas gave me the following piece of advice: “Treat the seedlings like I would treat my husband: put them in an unheated greenhouse, neglect them, and they will thrive.
- Plant them outside as soon as the soil can be worked.
Sowing Seeds in the Ground
- Sweet peas thrive when their roots are firmly planted in cold, wet soil and their heads are exposed to sunlight. Plant low-growing annuals in front of them if you can to provide shade for the roots.
- Pick a spot that drains effectively. If your soil tends to be acidic, it is recommended to add some powdered lime to the surface.
- Mix liberal amounts of compost or well-rotted manure into the ground to a depth of two feet to create a rich soil. (Learn more about adding amendments to the soil and getting it ready for planting.)
- You should dig a beautiful, deep “compost trench” that is around 4 inches deep before planting.
- After digging the trench, use a pencil to cut holes, place the seeds inside, and then press down on the earth to compact it and block out any light.
- The seeds should be soaked in water for 24 hours prior to sowing. To hasten sprouting, nick the seeds with a nail file before planting. In a temperate climate, seeds don’t need to be soaked.
How to Grow Sweet Peas
- Depending on the soil temperature, germination after planting can take anywhere from 7 to 15 days.
- Fill in the trench gradually as the seedlings appear and develop. Hoe additional dirt toward them.
- Keep the soil wet. Summer rains may be plentiful. Sweet peas can have bud drop; if you stick your finger into the soil bed to its first joint and the soil is dry, water them at the soil level and do so in the morning.
- You won’t need to fertilize if you plant with a lot of compost and aged manure. Use high potash feeds if you do want to supplement the diet because nitrogen feeds promote excessive top development.
- Mulch well once plants are planted to keep the soil cool and moist. Unless the soil becomes dry, you might not need to water your sweet peas if you mulch.
- Pinch off the tops when plants are 6 inches tall, not sooner, as this will promote the production of side shoots too early.
Provide Supports
- When temperatures rise above 65°F, sweet peas will begin to fade since they like chilly days and nights.
- Sweet peas are true climbers, with the exception of the bush forms. Provide them with sufficient support for at least 6 feet. Some species can reach heights of nine or ten feet. A braided willow obelisk, bamboo poles in the tee-pee design, or a trellis are examples of other attractive supports. If you don’t have a fence or trellis, give them something to cling on, such chicken wire, bushy twigs, or brush.
- Give the plants a good start by tying the first few stems to the support; the rest will follow. When they reach a height of 4 to 8 inches, use your thumb and forefinger to pinch out the middle growing point. Plants will grow stronger as a result.
Picking Flowers
- Pick flowers frequently for bouquets so that the plant will focus its energy on producing additional blooms rather than seeds. Up until the first frosts, the more you pick, the more they produce.
- Allow a couple of the final blossoms to mature into seedpods when the leaves begin to lose their color. On a windowsill, dry them, and then keep in an envelope in a dry location to sow the following year.
From miniature bedding kinds ideal for pots and borders without support to 8-foot-plus scramblers, there are sweet pea varieties for every setting.
These decorative peas are native to Sicily, where they have flimsy stems and a powerful orange-jasmine-honey aroma. Modern hybrids feature larger blooms and stronger stalks.
However, some of these contemporary kinds, despite having larger blossoms and more fashionable colors, lack the earlier sweet peas’ perfume. Sweet pea ‘Cupani’ is still rightfully well-liked and simple to grow. It has bi-colored flowers with maroon upper petals and violet “wings.”
The decadently fragrant “America” is an antique from 1896. When its petals open, beautiful red and white wavy stripes are revealed.
Look for antiques like the Sicilian “Old Spice” collection. Shades of white, cream, pink, lavender, and purple can be seen in this strain’s blossoms.
A new cultivar with enormous, creamy-yellow blooms with violet shading called “April in Paris” is aromatic.
Although the ordinary sweet pea is an annual, Lathyrus latiflolius, a perennial broad-leaved everlasting pea, is not fragrant. These clambering plants have a height of up to 6 or 7 feet, are hardy to zone 5, require little care, and bloom continuously from year to year.
- An essential component of a late Victorian garden is the sweet pea. Because of their wide range of colors and aroma, Victorians adored sweet peas.
- When the dew is still on the flowers in the morning, gather them. Their best aroma is at this time.
Before planting sweet peas, should I soak them?
- Sweet peas can be seeded in the fall in warmer places (Zone 7 and above) where the winters are generally not too harsh. Other than that, plant seeds in late winter or early spring. Before planting, give the seeds a 24-hour soak in water. By doing so, the seed coat is softer and the sprouting process is accelerated.
- Fill your planting containers with high-quality potting soil while the seeds are soaking. Use the deepest pots you can find because sweet peas develop a lot of roots. Ideal containers are 4-inch (10-cm) pots and root trainers.
- In each container, plant two seeds by pressing a fingertip into the soil and a half-inch (1.25 cm) deep.
- To boost humidity and hasten germination, cover pots with a plastic dome covering. Place in a warm greenhouse or a house window with good light.
- Pinch out the center growth tip, just above a leaf joint, once plants are 4 to 6 inches (10 to 15 cm) tall, leaving just two or three leaf nodes. The plant will be encouraged to branch out strongly from the base as a result.
- Because they use a lot of food, sweet peas need a little more care to produce in large quantities. Apply bone meal, a thick layer of compost or well-rotted manure, and a generous amount of natural fertilizer to planting beds to prepare them. Incorporate these elements thoroughly into the soil.
- Vines require a sturdy foundation to climb and grow quickly. Affix Hortonova netting or 6-foot (1.8 m) tall metal fence to the tall poles spaced approximately 8 feet (2.4 m) apart down the row for them to climb.
- Around the time of the final spring frost, plant seedlings outdoors in two rows, one on either side of the trellis, spaced approximately 8 inches (20 cm) apart down the row. It’s crucial to keep the vines bound to their supports as they erupt into lush growth. Sweet peas can grow more than a foot (30.5 cm) per week once the vines begin going.
- Sweet peas adore water, and they can’t survive without regular watering. Set up soaker hoses as soon as you plant them to prevent their luxuriant development from being restrained. It’s important to maintain their thirst quenched during warm weather. Use diluted fish and seaweed emulsion to feed plants once a week.
- Pick flowers when there are at least two unopened blooms remaining on the stem for the greatest vase life. To extend the life of the vase, add flower food to the water. It’s crucial to prevent plants from going to seed in order to prolong blooming, so be sure to regularly harvest and deadhead the flowers.
How are sweet pea seeds sown?
55° to 65° F, or 13° to 18° C, is the ideal range for soil temperature for sweet pea seed germination. In holes that are about two inches (two knuckles) deep, plant seeds. Fill each hole with two to four seeds, and spacing them four to six inches apart. Till seeds have sprouted, thoroughly water and maintain soil moisture.
How long does it take for the seeds of sweet peas to sprout?
To avoid mildew, sweet peas require a location in full sun, rich soil that drains very well, and sufficient air circulation. Increased organic material must be worked into clay-rich soil in order to improve drainage. Consider using raised beds for successful results if the soil is excessively wet.
If you are aware that summer heatwaves can come on suddenly, plant your sweet pea seeds where there will be some afternoon shade. For best results, carefully read the instructions on the seed packet. Proper plant spacing is essential. Slugs and snails should be kept away from seedlings. Use netting suspended over seedlings until they are 4 to 5 inches tall if marauding seed and seedling-eating birds are an issue.
Adequate water is a crucial requirement for all sweet pea varieties. If summer rain is insufficient to keep them evenly moist, be sure to water germination-stage seeds, seedlings, and vigorously growing older vines on a regular basis. If the soil is dry when your finger is inserted up to the first joint in the soil bed, water the plants.
Sweet peas are strong feeders, so add plenty of rich compost or well-rotted manure to the soil before planting. At least twice during the growing season, fertilize the soil with a thorough soil drench made up of one tablespoon of liquid kelp and one tablespoon each of fish emulsion. (Every few weeks, sweet peas grown in containers require regular fertilization.)
Aphids can be a problem for sweet peas; spray them off frequently with water. Sticky pheromone traps placed among the vines to attract and capture thrips, an opportune pest, can be used to efficiently control them. Mildew can be avoided with enough airflow and by not watering in the late afternoon and evening ( until the plants succumb to it naturally at the end of their bloom period.)
Almost any vertical support structure will allow all tall vining kinds to naturally grow up it. They will develop into strings, netting, wire, wooden, or pretty much any other sort of trellis. In the soil you can also utilize long branches that were left over after tree pruning. Wrap them in twine or netting so the tendrils can grip because they cannot twine around heavy poles like bamboo. It’s usually advisable to stay away from wire fencing in really hot climates like Texas. Before you sow the seeds or once they are a few inches tall, erect your securely anchored supports.
Between 75 and 85 percent of sweet pea seeds will germinate. There is always a little fraction that goes dormant, giving Mother Nature a refuge in the wild in case of bad weather. Only plant the seeds that have swollen and soak them in tap water for no longer than one night prior to planting in order to leave out the dormant ones. Never soak seeds; rather, nick them to let moisture seep into the seed coat for the highest possible germination rates. To accomplish this, simply cut a small hole with nail clippers in the seed’s outer layer; no chunk needs to be gouged out; this will allow moisture to enter the seed naturally. Although this nicking procedure takes more time, it will ensure excellent germination.
Plant seeds 2 to 3 inches apart and 1 inch deep. Depending on the climate and soil temperature, seeds can fully germinate between 10 to 28 days. Dig down to check if the seeds are still present if your sweet peas do not germinate well. Plant more immediately soon if they have decayed or been eaten since they will quickly catch up. It’s crucial to thin seedlings when they are several inches tall so that they stand about 5- 6 inches apart. This will provide the plants room to develop and flourish. Pinch off the top set of leaves when seedlings have three or four sets to encourage plants to branch out. Avoid significant changes in soil moisture during the active growing season by keeping sweet pea plants evenly moist. Mulching is a wise tactic.
Picking bouquets early and frequently can help you enjoy the longest season of spectacular bloom; the less you pick, the later the plants will go to seed and wither. Harvest flower stems frequently as the lowest blossom on each stalk just starts to open. Although stems may get shorter as the season goes on, the flowers are still large and gorgeous.
Sweet Peas Species
Our common garden sweet pea is the annual species Lathyrus odoratus; you can find them in a variety of colors and growth patterns, including:
tall varieties of vines
Depending on the region and season, these robust vines can grow to be 5 to 10 feet tall and produce numerous flower stems over a six to eight week bloom period. Tall vining plant species come in a variety of floral shapes:
Intense breeding efforts have been made in England to produce tall vining “Spencer” cultivars with bigger, waved and ruffled exquisite flowers. Because English breeders typically have been more focused in petal shape, form, stem length, and color than in perfume or weather tolerance, some Spencers are quite fragrant while others are very faintly so. Nowadays, Spencer kinds can be used to describe the majority of large-petalled, ruffled sweet pea cultivars. We stock the scented Spencer type “Blue Celeste.”
Mammoth and Royals are two American cultivars developed in the middle to end of the 20th century that have good-sized flowers, a light perfume, and are widely available. Since our only area of expertise is scented sweet peas, we do not provide these varieties.
Variety of Containers & Window Boxes
These tiny plants look great in containers and have stems that are 8 to 10 inches in length or have spreading and mounding characteristics. The heirloom varieties “Windowbox Cupid” and “Cupid Color Palette” are available from us.
Short, unable-to-climb Dwarfs
These sweet peas are short and don’t require vertical supports, with some varieties being tendril-less. It’s “Explorer” for us.
Other Species of Sweet Peas:
In the West, the perennial Lathyrus latifolius is frequently observed as a naturalized roadside wildflower. The cultivated form of this perennial, which is far more drought tolerant than annual sweet peas, can be trained to grow into an appealing and dependable permanent hedge plant. Although the flowers are plain, small, and odorless, their shape makes me think of miniature orchids. They come in rose, pure white, and shell pink. We market these colored mixtures as “Garden Orchids.” In zone 4 at Sweet Pea Gardens in Surrey, Maine, where they are quite hardy and over ten years old, Susan Keating has planted perennial sweet peas as a tall blooming screen on the side of her garage. Their flowering stalks also make lovely arrangement flowers.
This diminutive sweet pea, Lathyrus sativus azureus, features 1 inch dazzling azure-blue flowers and tangled grassy leaves. Plants only reach heights of 3 to 4 feet. attractive landscape accents in pots with minimal supports. We offer “Electric Blue” for sale.
Dr. Hammett is attempting to stabilize hybrids between several annual species in order to bring together lovely form and scent with fresh colors and heat tolerance. For home gardeners, the next ten years will bring some interesting new advances, such as real tricolor sweet peas and non-fading orange and apricot colours, all of which have potent fragrances.
Sweet Peas in Containers
Gardeners with patios, decks, or merely tiny gardening spaces can take advantage of the short, mounding kinds of sweet peas, like “Color Palette,” to enjoy their beauty and delicious smell. These small vines, which only reach a height of 8 to 10 inches, have delicately cascading branches and fragrant blossoms. A rose-pink and white bicolor as well as a combination of lavender, pink, dark purple, and mahogany are among the colors. Plant seeds immediately in deep containers with a minimum 8-inch diameter or rectangular window boxes with a minimum 6-inch depth in the very early spring. Always place seeds in planting containers 1 inch deep and 3 inches apart, in uniformly pre-moistened, high-quality, fresh potting soil. Germination takes 10 to 28 days when kept uniformly wet and in full sun.
Make sure to thin seedlings to 4 inches apart after they reach 2 inches in height (so, for example, you would leave 4-5 evenly spaced plants in a 12 inch in diameter container.) Plants can spread out and expand as a result as they get older. It’s crucial to remember to fertilize container sweet peas frequently (every two weeks) and to maintain them well-watered. Defend plants from snails and slug damage. Remove faded blossoms on a regular basis for the longest bloom. Mulch your containers and provide them with afternoon shade during the summer to extend their bloom.
