Sweet peas (Lathyrus odoratus cvs.) rank among the most beautiful annual flowers in my opinion. During the spring, these lovely vintage vines blossom for almost a month. The long-stemmed sprays of fluted and ruffled flowers emit an alluring medley of scents that make me think of orange and jasmine blossoms. A room literally smells like a sweet pea bouquet.
Even though cultivating and enjoying sweet peas as cut flowers is a tradition in gardening, these gorgeous blooms are frequently referred to as being “difficult to grow.” However, I’ve discovered that sweet peas are comparatively carefree and enjoyable to cultivate if planted at the appropriate time and given the right conditions. They are deserving of every gardener’s attention thanks to their huge variety of entrancing colors and eerie scent.
Sweet peas
Origins: This aromatic annual vine offers a wide range of varieties. Around 1699, a monk in Italy found the species.
Sweet peas need rich, well-drained soil and can grow in full sun to light shade.
Pests and ailments: Plants require space to encourage air circulation, which will prevent mildew issues. Birds, slugs, snails, aphids, and thrips can occasionally be a problem with sweet peas.
Propagation: Seeds should be used to start new plants. In locations with moderate winters, plant seeds in the fall or early spring. Start seeds indoors in the late winter in regions with harsh winters, and transplant in the spring.
Sweet peas require a lot of food, so fertilize them often throughout the growing season. Deadheading promotes a longer blooming season.
Sow seed in cool weather
For sweet peas to be grown successfully, there are some rules to go by. Plants require full sun to partial shade, well-draining soil, and good drainage. Sweet peas are prone to mildew, thus adequate plant spacing is necessary for proper air circulation. Until they are 4 to 5 inches tall, young seedlings must also be shielded from slugs, snails, and roving birds. Most importantly, seeds need to be planted and raised in cool climates.
Sweet peas are best planted in the fall, right after Labor Day, in regions with warm winters and hot summers. As a result, the seeds have more time to germinate and form strong root systems, which aid in the seedlings’ ability to survive the winter and grow quickly once springtime and longer days arrive. If you neglect to plant in the fall, start the spring seedlings as soon as you can in a spot that gets some afternoon shade. Sweet peas can be planted later in the spring for a late-summer bloom in areas like the Pacific Northwest that see mild winters and moderately chilly summers.
Sweet peas should be sown indoors in regions with chilly winters, then moved outdoors once the conditions are right. To prevent the roots from being disturbed during transplantation, sow the seeds in separate containers with a diameter of 3 to 4 inches. It’s crucial to avoid burying seedlings in the ground any deeper than in containers. Direct-sow seeds in a location that receives some afternoon shade as soon as the ground can be worked in the spring if summer heat or humidity develops quickly in your area. Unlike many other annual seedlings, sweet-pea seedlings are reasonably resilient and can withstand a mild frost.
Prep seeds and beds first
When you know when to plant your seed, you are prepared to move forward. A healthy sweet pea plant will have a germination rate of 78 to 90%. I’ve discovered that nicking the seeds is the greatest approach to improve germination after several years of testing. Create a small nick or cut in the seed’s outer layer using nail clippers. No piece needs to be gouged out; just make a hole for moisture to enter.
Choose a location with well-drained soil for straight sowing the seed. Before planting, add aged manure or compost to the soil and create a sturdy support structure. Up strings, wire netting, fencing, trellises, and tuteurs, I’ve grown sweet-pea vines. I wrap twine or netting over thicker poles so that the vines can grasp because their tendrils can’t climb on anything larger than 14 inches in diameter.
Plant the seeds 2 to 3 inches apart and 1 inch deep when sowing them in the garden. Dig down to check if they are still present if none of them germinate within two to four weeks, depending on the cultivar. Plant more immediately if any have decayed or been consumed because newly sowed seeds can catch up to those that have already sprouted quickly. It’s crucial to thin seedlings when they are several inches tall so that they are spaced 6 to 8 inches apart. This spacing encourages proper airflow, which reduces mildew issues and gives the vines ample room to develop.
Simply orient your sweet peas in the appropriate direction when they are 4 to 5 inches long to teach them to grow on a support. They will effortlessly climb up on their own once they have reached the base of their vertical support.
Use a balanced fertilizer to routinely feed these robust vines throughout their growing and blooming season. Keep the soil in your garden evenly moist but not soggy since sweet peas don’t tolerate big changes in soil moisture. Deadhead flowers to prolong blooming and stop plants from setting seed.
In addition to mildew, while sweet peas are in blossom they are vulnerable to aphids and thrips. Insecticidal soaps do not work effectively on these delicate blossoms. I’ve discovered that an intense water spray usually gets rid of the aphids. When blue sticky traps are strung among the plants, they are quite effective at luring thrips.
The story behind sweet peas
Father Cupani, a botanizing monk, originally found sweet peas in 1699 on an island off the coast of Sicily. Eckford, an Englishman, started hybridizing and selecting sweet peas in the 19th century, resulting in the introduction of grandifloras, which are cultivars that are larger, more exquisitely shaped, and multicolored.
In the English gardens of the Earl of Spencer, a naturally mutated sweet pea with even bigger and more impressive ruffled flowers was found in 1901. The gardening community appreciated these late-blooming, cool-climate Spencer sweet peas, and amateur sweet-pea breeding resulted in the development of plants with a variety of colors and little emphasis on smell.
Since then, American producers have created varieties that are more adapted to our hot, muggy summers. Many of the fragrant, smaller-flowered cultivars from the 19th and early 20th centuries are currently experiencing a rebirth. A lot of new types of sweet peas with exquisite form, color, and potent, robust scent are also being launched thanks to the work of sweet-pea breeders like New Zealander Keith Hammett, American company Bodgers Seeds, and English company Unwins.
A sampling of sweet peas
Garden sweet peas have beautiful, elegant blossoms that range in color from the most delicate pastels to rich, opulent colours. The majority of options are tall vines that can grow up to 8 feet tall in a single season. A few small, non-climbing border-type plants are also present; they only reach heights of 2 to 3 feet. Consider using the small, 8–10 inch long dwarf window-box sweet peas for containers. Here is a list of some suitable cultivars for gardens, along with details on their size and blossom color.
What height may sweet peas reach?
Sweet peas are available in a wide variety of hues and designs. The majority will only reach a height of 5 or 6 feet, while shorter “bush type” variants are ideal for containers. Pick a few different varieties to extend the flowering season. Find types that bloom early (“short-day”) and late by reading the seed packs (“long day). Even though annual sweet peas predominate, perennial sweet peas are also available (Lathyrus latifolia).
Start early
It’s crucial to start sweet peas (Lathyrus odoratus) blossoming early so they can survive the summer heat because they like chilly temperatures. As soon as the soil can be handled in the spring, you can plant them outside. The seeds will likely be alright even though it will likely still be very chilly. Sweet peas can be planted in the south in late fall for late winter or early spring blossom. Consult local cooperative extension to learn about best practices in your community.
Start your peas inside for the longest blooming season possible. Timing is determined by the date of your region’s last frost. Back up the date by four to six weeks once you get it. You should then plant. For instance, you should plant in early to mid-April if your last frost date is May 15. Don’t know when your region last experienced frost? Consult local cooperative extension or a reliable gardener in the area.
Are sweet peas trellis-required?
One of the best plants for cutting, sweet peas (officially known as Lathyrus odoratus) offer tempting colors and aroma for spring and early summer bouquets. The tiny flowers emit a grape-like fragrance into the air and come in a variety of beautiful colors. We enlisted the assistance of Barb Pierson, our nursery manager, to provide some guidance for individuals who have never grown Sweet Peas in a garden or a container pot. Any beginner or green thumb can benefit from a plentiful supply of these lovely flowers thanks to her advice.
Why do people grow Sweet Peas?
Sweet peas are cultivated for their lovely, ruffled blossoms, which come in pastel, blue, and bicolor hues. They are a beautiful cut flower since many types have scented blooms. The cultivation and breeding of sweet peas for both the home grower and the florist industry has a long history.
How do I go about growing Sweet Peas?
Sweet peas can be grown from seed that is treated before sowing or, more conveniently, from a starting plant. At White Flower Farm, we plant three seeds in each pot to create three Sweet Pea vines.
Where do I plant them and when?
In the northern half of the US, sweet peas flourish in the full sun. They can benefit from afternoon shade in the South. They are planted as early as possible in the spring since they prefer mild temperatures and cool roots. Newly planted seedlings will not be harmed by a mild cold. They can be sown in the fall and cultivated through the winter and early spring in highly warm climates. Compost should be added to the soil, and the area should be well-drained for optimal results. Sweet peas can be successfully grown in raised beds.
Do they need any special care while they are growing?
Sweet peas require support to grow and flower because they are climbing plants. Many other kinds of structures, like a trellis, supports made of mesh or wire, or fences, can be used. To sustain the weight of the vines, they require a sturdy framework that is firmly planted in the ground. The vegetation will develop tendrils that encircle the support you offer.
Since they like nutrient-rich soil, adding compost at planting time is advised. Mulching Sweet Peas will keep the roots cool and help them retain moisture as they grow.
Pinch the growth tips by one after the plants have reached a height of around six to encourage branching and the development of extra flowering stems.
What are the most common mistakes that people make with Sweet Peas?
- planting them in the middle of the summer They dislike the heat and won’t blossom as frequently.
- not offering assistance when planting. Once the plants have begun to grow, it is challenging to install your trellis or support.
- Lack of compost or fertilizer will cause weak plants and fewer flowers in poor soil.
- If Sweet Peas are planted too closely together without being thinned out, powdery mildew can grow and crowding lowers bloom production.
Do Sweet Peas produce pods that you can eat like the ones you find in the grocery store?
Despite having the appearance of snap pea pods, the seed pods are not edible. The pods and seeds can be saved in order to grow plants the following year. Remember that the plants that the seeds may grow may not be the same hue as the parent plant.
Will the plants come back again next year?
The plants are typically not winter hardy in most areas. They are replanted with new seed and plants even in warm climates to produce the most flowers and have robust development.
When do they bloom? Are there tips for getting extra blossoms?
Sweet peas will begin to blossom 4 to 6 weeks after they begin to show apparent vining. Whether or not the plants have been pulled back will affect the timing of the bloom. Although pinching may slightly limit growth, it will result in bushier plants with more flowers. In the spring and early summer, sweet peas will grow and bloom more quickly as the days lengthen. Compost or old dry manure can aid to supply nutrients for the growth of huge, many blooms. A fertilizer with a phosphorus to nitrogen ratio greater than one can also increase flower production.
What is the process for cutting the blooms?
Cut the blossoms early in the day to prevent the sun from drying them off. For your vase, select newly opened flowers with the longest stems. Just the side flowering stems of the plant should be clipped; leave the main stem alone.
Why should I get my Sweet Peas from White Flower Farm?
No seed treatment or waiting for germination is necessary because our plants are grown in our greenhouses in the spring and supplied to you at the ideal time for planting in your region. Our sweet peas arrive completely rooted and ready to plant in the ground in 4 pots, each containing 3 seedlings. You can avoid the time and hassle of starting sweet peas from seed by doing this. The quickest method to enjoy these beautiful flowers outdoors and in vases within your house is to purchase and plant our Sweet Pea seedlings.
How large are sweet peas?
Lathyrus odoratus is a flowering plant endemic to Sicily, southern Italy, and the Aegean Islands that belongs to the genus Lathyrus in the family Fabaceae (legumes).
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Where appropriate support is available, it is an annual climbing plant that can reach heights of 12 meters (3 feet 3 inches, 6 feet 7 inches). The sweet pea’s pinnate leaves have two leaflets each and a terminal tendril that twines around plants and other supports to aid in climbing. The flowers of the wild plant are purple and measure 23.5 cm (341+12 in) in width; those of the numerous cultivars are larger and have a wide range of color. Flowers typically have a strong smell.
It’s possible to mistake the perennial everlasting pea, L. latifolius, for the annual species, L. odoratus.
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Choosing sweet peas and perennial peas
The major consideration is whether or not aroma is crucial to you when deciding between perennial Lathyrus and sweet peas. Decide if you would then like an annual or perennial plant. There are several color choices available as well as climbing and bushier varieties.
Fragrance
Choose sweet peas (Lathyrus odoratus), which are generally very fragrant, if you enjoy a pleasant garden and sweet-smelling flowers for indoor use.
Lord Anson’s blue pea (Lathyrus nervosus), a perennial Lathyus, is an exception to the rule since it does have a perfume.
How long the plant lasts
After setting seed, sweet peas (Lathyrus odoratus) only have a one-year lifespan. However, don’t let this deter you because they are quite simple to grow from seed. Lathyrus latifolius is an example of a perennial species that returns every year, however there are fewer options and they typically lack smell.
Colour
The annual sweet pea (Lathyrus odoratus) has a large variety of blossom colors, including bicolored varieties. However, the perennial varieties do come in some uncommon colors, like yellow and orange.
Habit
The majority of Lathyrus are climbing plants, therefore support them with canes, netting, or allow them to climb over a bank or through a bush. For ground cover and pots, clumping varieties like the spring-flowering Lathyrus vernus and dwarf bushy sweet pea varieties like “Snoopea” and “Bijou Mixed” are excellent choices.
Buying sweet peas and perennial peas
Although many garden centers also sell a few sweet pea seeds in packets, the largest assortment of sweet pea seeds may be acquired from internet seed suppliers. In the spring, several nurseries and garden centers sell pots of germinated sweet pea seedlings that can be divided into individual plants and raised in pots before being planted outside.
There are a few seed specialists who sell perennial Lathyrus seeds, like Lathyrus latifolius, but many gardeners opt to purchase the plants instead. The plant you’re looking for can be found using our Find a Plant tool.
When to plant sweet peas and perennial peas
- Annual sweet peas should be sown either in late January or early April and planted out in April.
- Sow perennial Lathyrus in the spring or the fall.
Where to plant sweet peas and perennial peas
Locate a sunny area where there is room for the plant to grow or to bush out (depending on its habit). Also acceptable is a little light shade, especially for Lathyrus grandiflorus.
How to plant sweet peas and perennial peas
- To avoid cold shock, indoor seedlings should be hardened off for 10–14 days before being transplanted outside.
- Ideally, four weeks before planting, enhance the soil by incorporating a soil conditioner like garden compost or manure.
- Sprinkle general-purpose fertilizer, as directed on the pack, into the area where you plan to plant it, such as Growmore, Vitax Q4, or blood, fish, and bones.
- Before planting, water your plants thoroughly to hydrate the roots.
- Remove pots from larger plants and ease seedlings out of modules or pots while being careful not to snap or crush the stems.
- Plants should be separated by 20–30 cm (8–1 ft).
- Place climbing plants near to their intended support (within 5-7.5cm or 2-3in), with two plants at the foot of each cane if they are climbing a wigwam.
- After planting, water once more to help the soil surrounding the roots settle.
Use garden twine or sweet pea support rings to secure young climbing plant shoots to canes, pea sticks, netting, trellis, or shrub shoots that they will be growing up. Tendrils in contact with supports will naturally start to cling on, but if any are straying or in danger of snapping, keep tying in new shoots.
In dry weather, check on plants in the ground every 3 to 4 days and on those in containers every day because they won’t flower as well if they become too dry. Each time you water, be sure to use enough water to completely moisten the roots.
Apply a high potassium liquid fertilizer, such as tomato feed, once or twice a week on light or infertile soils. This promotes flowering, particularly in annual sweet peas (Lathyrus odoratus).
Pick or remove dead flower heads as frequently as you can once flowering starts. For annual sweet peas (Lathyrus odoratus), which will stop flowering if seedpods are allowed to form, this is especially crucial.
Pinching out
When plants are around 7.5 to 10 cm tall, pinch out the shoot tips of new spring-sown sweet peas for gardening (3-4in). This promotes robust side branching. Autumn-planted seedlings frequently naturally branch.
Cordons
Pick the strongest shoot and keep pinching out all the tendrils and other sideshoots as they grow whether you want to enter your sweet peas in a local show or just want to maximize the size of blossoms for cutting. By using this technique, the plant directs its attention to the blossoms. The term “cordons” is used to describe these single-stemmed plants.
One stem per bamboo cane or tall stake needs to be tied to them on a regular basis. To keep the shoot in place as it grows, you can use twine looped in a figure-eight pattern around the cane and stem. Use sweet pea rings, which are wire loops that wrap around the stem and cane and are lightly squeezed until they hold, to make things simpler.
Cordons have the potential to grow much taller than the typical 2 m (6 1/2 ft) estimated height.
Cutting back
Cut perennial Lathyrus back to the ground in the fall, or better still, wait until February to do it so the dead stems can serve as wintertime cover for wildlife. When flowering is ended at the end of the summer, annual sweet peas can simply be pulled out and composted. This might happen a little bit sooner during hot, dry seasons.
Methods
Sweet peas can be immediately sown into the ground in April, or they can be planted in seed compost pots in the fall or spring. Although it takes more time, pot-sowing is typically more dependable than direct sowing. If you plant in the fall to enhance your chances of getting early blooms, keep seedlings in a coldframe or cold greenhouse over the winter to protect them from growing lanky. Keep the coldframe’s lid elevated unless a strong frost is anticipated. Sweet peas planted in the spring flower in 12–14 weeks.
Sweet pea seeds frequently have a tough outer covering that makes them more challenging to germinate. Place your seeds on a layer of damp vermiculite or kitchen tissue and store them in an airtight container in a warm area. As soon as the seeds swell or start to sprout, plant them. Some gardeners like to soak the seeds overnight instead, but if you don’t plant them right away thereafter, they might rot. With a sharp penknife, chip off a little portion of the hard seed coat to allow moisture to enter and promote germination on recalcitrant seeds that haven’t swelled.
- Individually sow seeds in seed compost-filled rootrainers or 9 cm (3 in) pots. As an alternative, sow five to seven seeds per 13 cm (5 in) pot, spacing them 2-3 cm (3/4-11/4 in) apart.
- Add 1 cm (1/2 in) of vermiculite or compost to the top of the seeds.
- Add water and maintain at around 15C. (59F)
- It is optional to cover the pots with clear polythene or glass to reduce the likelihood that they will dry out, but keep in mind to remove the covering after the seeds have germinated.
- Once they have grown to around 3.5 cm (11/2 in), carefully transplant single seedlings into 9cm (3 in) pots if you have seeded them several to a pot.
- Use your thumb and finger to pinch out (remove) the top of the shoot just above a healthy leaf when the seedlings are 7.5–10cm (3–4in) tall. This will promote side branches, which are always stronger than the core stem that has been removed.
- At least four weeks before planting, remove all weeds from the soil and add a soil enhancer, such as garden compost, manure, or composted bark.
- Only plant seeds as the soil begins to warm, typically around April.
- To create a wigwam, plant any temporary supports, like pea sticks or bamboo canes, in the ground.
- Take out a shallow drill of dirt 2.5 cm (1 in) deep for rows of sweet peas, and plant a seed every 5 to 7.5 cm in it (2-3in)
- Seedlings should eventually be spaced 20–30 cm (8–1 ft) apart to provide the plants enough room to flourish. The extra seedlings may seem like a waste to compost, but unless treated carefully, their roots are typically too damaged to recover.
- Push two seeds into the ground at the base of each cane to a depth of 2.5 cm (1 in) when sowing around a wigwam of canes.