How To Grow Sweet Peas – Plant & Care Guide

Updated/Fact-Chacked on June 20, 2023 by Gareth James

This year I tried growing sweet peas for the first time in some 2ft containers.  The idea was to grow them up on one of my fences to provide some privacy (as my fence has gaps), while providing summer scents and cutting flowers.

Sweet Peas (Lathyrus Odoratus) are universally loved. They belong to the pea family (Fabaceae), and they fall in the category of climbing plants.  Most gardeners grow these plants due to their beauty and fragrance.  However, this wasn’t always the case. Nurseryman Henry Eckford is credited with developing the sweet peas we grow and love today. Here is a simple guide on how to grow sweet peas.

Sweet peas can be grown in many ways. For instance, you can grow them along the fence to create an aesthetically pleasing wall of colour. Other people grow them on bamboo tripods, pots, or on the ground.

Best Conditions for Growing Sweet Peas

1. Light

Sweet peas flourish in full sun. If you are growing them in a warm climate, locating the plants in a place that enjoys shade in the afternoon is recommended.

2. water

When growing sweet peas, you must keep the soil moist. You can achieve this by watering the plants every couple of days. Before you water the sweet peas, drive your fingers into the soil for about an inch. If it is dry, it’s time to water it.  But if it is moist, you can leave it like that.

3. soil

Sweet peas require fertile and well-drained soil.  A 7.5 soil PH is perfect for growing these plants. Adding compost may help to improve the quality of the soil.

4. Temperature and humidity

Sweet peas first grew in the Mediterranean. This means that seedlings are tolerant to light frost. However, the plants cannot withstand extremely hot conditions.

5. Fertilizer

Sweet peas need to be fed well when growing.  The best fertilizer for them is a potassium-rich fertilizer.

How to Plant Sweet Peas

Sweet peas are easy to grow from seed, but you can buy plugs from garden centres during spring, which will be much easier. Our steps cover growing from seed.

Step 1: Prepare the seeds

Buy sweet peas seeds from the nearest gardening store. Soak them in water for a few hours or nick them with sandpaper or clippers. The objective is to aid germination. If you prefer to soak them in water, ensure that you select the seeds that swell. Those that remain intact may take a longer time to germinate or not grow at all.

If you plan on planting indoors, propagation trays work best.  The idea is to avoid interfering with their rooting while transplanting.

Ideally, add 3 seeds to each square and keep the strongest seedlings; pluck out any that look weak.  Adding more seeds to the group does not equate to more flowers from the group, strong sweet pea seedlings will produce the most flowers.

Producing sweet pea seedlings can be tricky, it might take you a few attempts.  My first batch went ‘leggy’ very quickly due to the lack of light in a north-facing window. I still planted them in a pot for a test batch, but the plants produced very few flowers.

If you don’t want the hassle of trying to propergarte seedlings, most garden centres and plant nurseries will sell sweet pea plugs in spring. If you are looking for something unusual, then Sarah Raven has a lot of fantastic varieties.

Step 2: Harden sweet pea plants

For best results, harden your young plants before planting them out fully.  Allow them to sit outside in a sunny spot during the day and bring them back in at night for a couple of weeks.

Young sweet pea plants are best fully planted out around mid-may when the risk of frost has passed.

Step: Tie plants to a  trellis or bamboo sticks for support

Choose a sunny location to plant the vines. See to it that they do not suffer from the harsh suns shining in the afternoons. Since they are climbing plants, sweet peas will need a trellis or bamboo to be tied to.. Whatever you decide to use should be at least a quarter-inch thick or so.

It is paramount that you use mulch to keep the soil underneath cool and protect the roots. If the rainfall is unreliable, water the plants regularly and feed them with a liquid-based fertilizer every 15 days.

Update 2022

An alternative supporting method is to grow them up the side of a wall or fence using a trellis. This year I grew them up a fence with a cheap rope trellis I bought online.  I planted x9 sweet pea plants in x3 2ft containers, running along my fence to try and provide some privacy screening. They did grow well but only reach around 3ft, I thought I could get a bit more height with my constant attention.

Step 3: Pick them frequently

You want to keep the vines as productive as possible. To do so, you must cut the flowers routinely. Get rid of any fading blossoms. During the summer, vines may start turning brown and dying. This shouldn’t cause any alarm because it is normal. When this starts happening, it is time to pull the sweet peas out and replant your garden.

We recommend picking every 10 days for maximum flowering and reducing the chance of seeding.

Best Sweet Pea Varieties to Grow

Here are a few great sweet pea varieties to grow. A lot of these are annuals so you are looking for flowers every year, specifically research perennials varieties.   Sweet peas come in a huge variety of colours, so you have a lot of choices if planning to combine varieties. You can also buy them with rippled effects where the outside of the petals have dark edges, while others look like they have been sprayed by a graffiti artist.

If you are looking to grow sweet peas for cut flowers, consider Grandiflore sweet pea. This variety was developed by the horticulturist Henry Eckford are considered a classic variety from the 19th century.  Spencer sweet peas also work well in vases and often win major awards.

The Lathyrus genus of sweet pea now has over 200 varieties and average around 4t in height, while the Grandiflore and Spencer can grow to over 6 ft.

You can also buy dwarf sweet peas which are around 10″ in height, ideal for pots and hanging baskets.

Lathyrus odoratus — Painted Lady

The painted lady is a classic sweet pea and bi-coloured pink. It’s a tiny flowering sweet pea but the has a really strong smell – perfect for a fragrant garden or if you want to introduce scent to a seating area.

Notes: – Heavy-scented, fortnightly feeding, regular watering, full sunlight.

Lathyrus odorous — Fire and Ice

One feature that makes the Fire and Ice a great garden choice is that the more you pick its flowers, the more flowers it produces. Radiant blooms of creamy-white over purple helps to make its petals stand out in a garden. The strong fragrance from the Fire and Ice will freshen the scent of the whole of your border.

Notes: – Non-edible, susceptible to rot and slugs, attracts pollinators, great for twining through arches.

Lathyrus odoratus – ‘Watermelon’

This modern grandiflora Sweet Pea is what I am planning to grow this summer. The salmon-pink flowers look fantastic when fully in bloom and standing tall at around 1.8M heigh.

Notes: Work well when combined with light blue sweet

Lathyrus odoratus — St. George

The primary red or white petals of St George will stand out amongst any other flowers you have in your garden. A low spread of 30 centimetres means that it will not encroach too far into the territory of your other plants, though it will grow up to 2 metres tall. This flower survives well after cutting and, in a vase with enough freshwater, will stay alive for prolonged periods indoors.

Notes: – Toxic to house pets, safe for wildlife and people, summer flowering.

Lathyrus odorous — Almost Black

The Almost Black is a great starter, Sweet Pea, for beginner gardeners, though it is still prone to attack from common small pests and diseases. The Lathyrus odorous will climb and grow up to two metres and, being deciduous, will keep its grey-green leaves throughout the year. This Sweet Pea blooms flowers of deep maroon in the summer.

Notes: – Low-toxicity, enjoys mineral-rich soil, full sunlight.

Lathyrus odoratus — Promiscuity

The Promiscuity produces a powerful scent and bi-chromatic petals of pinks and white. Flowering begins in June and should continue until late August. The Promiscuity is a good choice for those looking for something to trellis, but it will need regular watering. For the best flowers, promiscuity needs full exposure to sunlight and regular deadheading.

Notes: -Toxic for pets, safe for wildlife and humans.

Lathyrus odoratus — Hi Scent

The Hi Scent is known for its wavy white picotee petals that merge into subtle pinks at the outer edge. The Hi scent is one of the most fragrant of the Sweet Pea family. The stems will also grow to heights of up to 2.5 metres with the support of a wall or trellis. Though safe in many ways, it is advisable to wear gloves and wash hands after handling, as the Hi Scent can cause stomach issues.

Notes: – Fortnightly feeding, regular deadheading, prefers humus-rich soil.

Lathyrus odoratus — Percy Thrower

The Percy Thrower has a strong scent, making it a pleasant addition to a gardener’s flowerbed. This is a climber that you can expect to reach up to heights of two metres, with a spread of around 30 centimetres. The best results come from planting in well-drained soil.

Notes: – Creamy-purple petals, green stems, resilient to most weather conditions.

Lathyrus odoratus — Pandemonium

The Pandemonium is known as a flake Sweet Pea, one with predominant white petals with overlaying stripes ’flakes’ of dark pink. The Pandemonium’s strong stems make it resilient to most weather conditions, though it grows best in full sunlight with regular watering.

Notes: – Regular deadheading will prolong flowering, a good climber for a trellis or obelisk.

Lathyrus odoratus — Lipstick

The Lipstick offers up a fantastic combination of strong fragrances from its crimson red flowers while in bloom. The distinctive wavy petals look great in a border or cut to display in a home. The Lipstick needs little attention and will breathe colour over walls as it works its way up a 2-metre trellis.

Notes: – Non-edible, summer flowering, fortnightly feeding.

Lathyrus odoratus — Geranium Pink

The Geranium Pink is one of the more popular Sweet Pea varieties as it grows well in most soil and weather conditions. The Geranium Pink will grow to a little under two metres with the help of a trellis and spread to around 30 centimetres. This is one of the Spencer-type Sweet Peas that exhibit large frilly flowers and long stems.

Notes: – Vibrant pink petals, delicate fragrance, wildlife safe, toxic to pets, prefers mineral-rich soil.

Growing Everlasting Sweet Peas – (Perennial Sweet Peas)

After growing annual sweet peas this year, I’ve decided to grow more perennial sweet peas next year – probably up my pergola posts. They are so easy to maintain once established and will produce flowers every summer for years.

When deciding between perennial Lathyrus and sweet peas, the primary consideration is whether the fragrance is essential to you. Then determine if you want a yearly or a perennial. There seem to be a variety of colours to choose from and climbing and bushier varieties.

An everlasting pea is sprouted similarly to annual peas, except that it is always planted during spring. Sow in small containers or seed trays with peat-free topsoil anytime between February and March. To germinate, keep the seeds warm, about 18C for ten days.

When the plants are large enough to accommodate, pot them on and move them outside to toughen off before planting. The everlasting pea is a hardy perennial that is simple to germinate.

Choose a sunny location with enough room for your plant to rise or bush out, varying on its behaviour. For Lathyrus grandiflorus, just a little light-dappled shelter is also acceptable.

Tips on how to grow perennial Sweet Peas

-To avoid cold shock, toughen the seedlings planted indoors for at least 10-14 days before planting.
-Combine in a soil improver like manure or garden compost for around four weeks before you plant to prep the soil.
-Sprinkle some all-purpose fertilizer into the plantation area according to the package directions.
-Water the plants thoroughly before planting to ensure the roots are well-watered.
-Remove the seedlings from modules or pots gently without crushing or snapping the stems, and from the larger plants, remove the pods.
-Plants should be spaced 20-30cm or 8in-1ft apart. Place the climbing crops near the intended help; within 5-7.5cm or 2-3 inches, with two crops at the bottom of every cane if climbing up a wigwam.
-After planting, water again to rest the soil around the roots.

Although they can tolerate some shade, the Everlasting Pea blooms well in full sun. Its growth is comparable to that of a yearly sweet pea, with tentacles clinging to obelisks, trellises, and nearby shrubs, and it’ll scramble or climb over them.

Its H7 is hardy, which means it can withstand even the harshest winters. It doesn’t care if the ground is alkaline or acidic, clay-based, or otherwise, but it prefers rich soil with enough moisture. You can battle powdery mildew by ensuring that it has sufficient water.

Everlasting Sweet Pea Maintenance

Cut it back hard to keep pea Lathyrus latifolius from overgrowing and becoming out of control. Trimming will inspire more growth. For more flowers, deadhead sweet peas bloom all through the planting season. Also, to protect the plant from toppling over, stake it and offer a trellis or other climbing frameworks as required.

Ensure to reduce the crops down to ground level at the start of the growth period, in springtime. Remove any dead development from the climbing structure or plant’s trellis.

Everlasting sweet peas grow rapidly over the summer months; you need to keep tying them to your trellis.  I was away for a few weeks this summer, on my return, my everlasting sweet peas were spreading across the ground over my lawn.

Diseases and Pests to Look Out For

There are a host of viruses associated with sweet peas. These include;

• Bean yellow mosaic virus
• White clover mosaic virus
• Pea mosaic virus
• Pea enation mosaic virus

Their symptoms are dead spots on the leaves, white-streaked leaves, loss of vigour, translucent leaves and, so on.

If you see any of these symptoms on your sweet peas plant, you may use a chemical or non-chemical control method.  The best option is to destroy the affected plants and leave the rest. Also, always buy high-quality seeds because these viruses are not seed-bone. Some legume weeds such as clover may bring the virus. Therefore, weeding is necessary. If you strive to meet the growing conditions we have listed above, chances are that you will not have to deal with viruses.

Aphids, anthracnose, and blindness may stunt your peas, luckily there are many ways to stop them. Insecticides are the most effective solution to stop aphids. Unfortunately, there is no known remedy for anthracnose. As for blindness, you will have to uproot and discard the affected plants. This will give the rest a chance to thrive.

If you derive immense fulfilment from gardening and looking after plants, you should try to grow sweet peas. Following the guidelines that we have outlined on this piece should help you out. And there we have it, a simple guide on how to grow sweet peas.

What’s The Difference Between Sweet Peas And Green Peas?

Both green peas and sweet peas are prevalent garden plants, but they are vastly different and are grown for various reasons.

Edibility

A sweet pea, the popular shortened version that grandmas everywhere adore using, is a famous ornamental plant, especially in the United Kingdom, produced for its fragrant flowers. It’s a flowering crop that has lovely purple and pink flowers.

Note that the sweet pea is not a pea; its plant’s seeds are poisonous and not safe to eat! The seed pods may resemble edible pea pods; however, they are toxic and should not be consumed.

Green Peas, also known as sugar or snap peas, are a famous vegetable garden plant grown for eating. Both crops produce seeds and pods, but the seeds of sweet peas are poisonous to humans if consumed in large quantities. On the other hand, regular garden-variety peas are sometimes referred to as sweet peas, where misunderstanding arises.

The peas you shell are sweet

Sweet peas are simply a type of garden pea widely grown and prized for their sweet taste and bright, attractive green colour. Before you eat them, you’ll have to shuck them—so here’s what you ought to know: A pea pod is approximately 1-1.5 cups of shelled peas.

Sweet peas and English peas are other names for garden peas. The round peas inside the firm and rounded pods must be eliminated or shelled before consumption. Those peas are yummy and can be ingested cooked or raw; shelled and frozen peas are the most commonly sold peas.

Most people use English peas to add some colour to a variety of dishes, from steamed rice to pot pie stuffing, but also, they can take centre stage. They’re simple to locate in the frozen meal section of the grocery store, even without or with carrots, but they’re also tasty and eaten raw whenever they’re fresh. Alternatively, you could indeed blanch, puree, or sauté them.

Suppose you have a surplus of fresh peas from your garden, in a layer on a baking tray, freeze them. And ensure to keep them in a sealed container.

Flowering

Sweet peas are grown for their flowers, which come in various colours such as white, pink, red, and purple. The most significant percentage of the flowers have a moderate to strong scent. Although edible peas are primarily white, some variants come in purple flowers. The amount of flowers manufactured by many sweet pea types is higher than edible peas.

Green Peas are eaten wholly!

Snow peas and snap peas are two popular pea varieties. Unlike the English peas, they have soft pods that you can devour with the peas there; however, you must still remove the strings before cooking.

Best Places to Buy Sweet Pea Seeds and Plants

Eagle Sweet Peas is a specialist sweet pea grower who develops their own varieties, they try and bring out a new one every year. Eagle Sweet Peas can be found at the Chelsea Flower show among many other flower shows. Last year they released Rebecca sweet pea and the Allan Hodgeson sweet pea before that.

Sweet Pea FAQs

When do sweet peas flower in the UK?

Sweet peas generally flower from June to the end of August but can be prolonged into November with good management and warm conditions. Some varieties will also have longer flowering seasons.

When to plant sweet peas?

Sweet pea seeds are best planted in March undercover, while small plants should be planted out around May.

What to do with sweet peas when finished flowering?

If they are annuals, you can compost all the dead foliage and leave the roots in the soil as they have high in nitrogen and will give you great soil.

Do you have to deadhead sweet peas?

Yes, it’s best to maximize the flowering.

What is the world’s strongest scented sweet pea?

According to Sara Raven, a big sweet pea enthusiast, ‘Matucaca’ is the strongest scented sweet pea plant variety in the world

Do sweet peas attract honey bees?

Bees are more attracted to the perennial sweet pea with less scent, though the heavily scented annual sweet pea varieties will attract other pollinating insects.

How long do sweet peas take to mature?

It takes 90 to 120 days before sweet peas mature and start to produce flowers. Once these plants die off, they will not grow by themselves next year. However, you can save the pods so you don’t need to buy seeds for the next season.

Mary

Mary shares a passion for gardening with her husband John, though she is more focused on growing veg on their allotment at St. Margaret’s Allotments, Durham. Mary also works in the lawn care industry and manages the lawns for the Durham University campus.