When Do Sweet Peas Bloom

Long-day sweet peas, as their name suggests, begin to produce flower buds when the days are longer than the nights. Because of this, they bloom between spring and summer and are frequently referred to as spring- or summer-flowering sweet peas.

When are sweet pea flowers in bloom?

Depending on where you live and how hot your summers get will determine when the sweet pea (Lathyrus odoratus) flowers. With their fragrant pea-like flowers blossoming in a variety of colors, these annual climbers are eye-catching additions to containers or outdoor spaces. Success is ensured by planting at the appropriate time of year for your locality.


Depending on where you live, the sweet pea flowering season happens during several seasons. Flowers will bloom in the late spring and into the fall in regions with cooler summer temperatures. Those who reside in warmer climates can look forward to flowers in the winter and spring.

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.


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.


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.


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.


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.


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.

Perennial peas

In the spring or the fall, divide bigger plants. If you want to divide Lathyrus vernus in the spring, wait until after flowering.

Unfortunately, very few of the issues with sweet peas and perennial peas are extremely problematic.

  • Powdery mildew, which is brought on by drought or insufficient hydration, results in a grey leaf coating.

Why don’t my sweet peas have flowers?

Lack of sun, extreme heat, or too much fertilizer are common causes of your sweet peas’ failure to bloom. Native to the Mediterranean region, sweet peas bloom best in full sunlight, medium to low nutrition soil, and routine irrigation. Heat waves can momentarily stop flowers from blooming.

Continue reading to find out the best ways to encourage blossoming in your sweet peas and why they aren’t blooming.

when are sweet peas in season?

Although June and July are the primary flowering months for sweet peas, depending on when you planted and sowed them, they may begin to bloom earlier or later. To extend their growing season, keep watering, feeding, and deadheading.

how to germinate sweet pea seeds?

However, I have observed that sweet pea seeds germinate within 2 weeks with or without soaking. Some people advise soaking sweet pea seeds to assist them germinate; you may find it beneficial to leave them on some damp kitchen paper for 24 hours before sowing.

can sweet peas grow in shade?

Because they are sun-loving plants, sweet peas do best in locations with lots of sunlight. They will not flower as frequently even if they can grow in sunny or dappled shade.

How to sow sweet pea seeds

Sweet pea flower seeds are frequently advised to be nicked or chipped before planting, as well as to soak in water or damp paper towels for the night, although none of these steps are necessary. Sweet peas thrive in root trainers, which are unique tall plug trays, or 9cm pots since they prefer to have a long root run. But a toilet paper roll’s cardboard interior will also work.

Individual seeds can be sown in toilet paper inners or root trainers, or two to three seeds can be planted in a 9 cm pot. The container should be filled with seed compost, dampened, and then the seed should be pushed in with your finger to a depth of about 1 cm. Add some compost to the top and gradually water. Put the pots in a protected area that is well-lit. Unlike other seeds, they do not require additional heat from a propagator. When the seedlings emerge, place the pots somewhere sunny and cold, ideally between 5 and 10 degrees Celsius, or else they will grow long and lanky.

What month do you plant sweet peas?

Sweet peas can be purchased as plug plants or are produced from seed. If starting from seeds, you can plant them in the spring (February to April) or the autumn (usually October or November), and then nurture the seedlings into little plants.

Autumn and early spring seeds require a frost-free environment to thrive, such as a cold greenhouse or cold frame. It is better to wait and plant the seed later, in April, when you can start them off easily on a windowsill inside, if you don’t have a place that is cool and light like this. Alternately, in late April and early May, direct-sow outdoors in larger pots or the ground.

best varieties of sweet pea flowers

  • The two-toned, dark pink and purple blossoms of Lathyrus odoratus ‘Matucana’ have one of the greatest fragrances of any sweet pea. BUY NOW
  • The strongly fragranced Lathyrus odoratus ‘Erewhon’ blooms in exquisite mauve-pink and pastel blue hues. BUY NOW
  • Lathyrus odoratus ‘Lord Nelson’ has deeper navy-blue to purple flowers that are smaller but intensely fragrant and produced in greater numbers per stem. BUY NOW
  • An antique variety of annual sweet pea with vivid reddish-pink blossoms is called Lathyrus odoratus “King Edward II.” BUY NOW
  • Popular early-flowering sweet pea Lathyrus odoratus “Painted Lady” has dark pink and light pinky-white petals.
  • Hardy perennial sweet pea Lathyrus latifolius ‘White Pearl’ has all-white blooms. It doesn’t have a perfume yet consistently returns year after year and blooms until the fall. BUY NOW

How to grow and care for sweet pea flowers

When your sweet pea seedlings are about 10 cm tall after spring sowing, you can pinch out the tips to help them develop into vigorous, bushy plants with lots of flowering side shoots. Just above a pair of leaves, place the growing point at the top of the stem between your finger and thumb, squeeze it, and snip it off. Avoid pinching the tips of plants seeded in the fall.

Prepare your seedlings and plugs for growing outdoors by hardening them off after there is no possibility of frost, often starting in late May. To help them get acclimated to the cooler weather, this entails leaving them outside during the day and bringing them inside at night for about a week.

Their final growing location should be in a sunny, open area with fertile soil that has good drainage. Because they climb, annual sweet peas require a support to develop. trellis, netting, a cane teepee, a border obelisk, or a garden arch are typical examples. Plant the sweet peas 15-20 cm apart, 5 cm from the base of the support you’ve chosen.

If grown in pots, plant the compost with some slow-release fertilizer to keep the plants healthy all season. Keep the plants well-watered and keep an eye out for slug and snail damage.

Sweet pea blossoms should be secured to their support as they enlarge using garden twine or support rings. Once the sweet pea blooms begin to bloom, routinely treat them with tomato fertilizer. Continue picking flowers throughout the summer because the more you pick, the more are generated.

Do sweet peas come back every year?

Sweet pea blooms come in annual and perennial varieties. Lathyrus odoratus, an annual plant that must be sown from seed every year, is typically a climber with a strong fragrance. Every spring, the perennial or “everlasting” varieties of Lathyrus latifolius reappear, however the majority of them have little or no perfume. Some don’t climb; they are bushy.