Perennial Sweet Pea, also known as Everlasting Pea, is a traditional herbaceous perennial climbing vine with stunning, vivid blossoms that can reach heights of 10′. Summer is when this plant blooms, with the blossoms rising above the foliage on long peduncles. It can be trellised or used to cover a fence or other structure because it climbs by tendrils. It can cover a bank and forms a neatly mounded ground cover. Its decorative attractiveness is aided by the leafy wings on the stems. Winged stems and ternately complex leaves, with the third leaf being a 3-branched tendril, are important distinguishing characteristics. This plant needs well-drained soil and direct sunlight. To multiply seeds, pre-soak them in water for a few days before planting them in the early spring at a depth of less than half an inch. This plant resists being moved, and there are no significant pest issues.
Do sweet peas return each year?
Although Lathyrus odoratus, the most popular sweet pea variety, is an annual, there are also perennial forms available (Lathyrus latifolius).
- 1. Annual sweet peas are plants that go through their entire life cycle in a single growing season. They grow, produce seeds, and perish within the span of a year, just like other annual crops. The next year, you must replant new plants in your garden if you want to grow them again. The majority of sweet pea species are annuals.
- 2. Perennial sweet peas: These flowers reappear each year. After the growth season is over, you don’t need to replant them because they will keep growing for a longer period of time. Although there are fewer types of perennial sweet peas available and they tend to lack the traditional sweet pea aroma, they may be simpler to grow.
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.
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.
How do sweet peas fare during the winter?
There are few flowering plants that can compete with the sweet pea for my affections since it is hauntingly gorgeous, incredibly fragrant, floriferous, colorful, and surprisingly simple to grow. Without the ruffled, transient beauty of its tiny blossoms or its endorphin-inducing, evocative aroma, which compels you to bury your face in its delicate petals and inhale slowly and deeply, no summer garden is truly complete. It makes sense that many gardeners refer to this enormously ornamental pea family member as the “queen of the annuals.”
As you may already be aware, an annual plant is one that lives for no longer than a year, and in some cases much less, depending on the species’ capacity to endure the winter cold. Some of the shorter-lived varieties, referred to as half-hardy annuals, can only be seeded in the spring outdoors after the soil has warmed up or under cover and gentle heat.
Instagram is strewn with photographs of seedlings of woefully invalid sweet peas, which are the terrible outcomes of helicopter gardening, displayed in a proud manner.
Sweet pea is actually a hardy annual, which means that despite the delicate, transitory beauty of its blossoms, it can withstand a surprising amount of frost (down to minus 5 degrees), and as a result, it grows well from an autumn seeding. You will receive larger, stronger, sooner-flowering, longer-flowering, better-performing, and more durable plants from seed sown between now and the end of November than from seed sown in late winter or mid-spring (with longer flower stems).
How is it sown? The first step is to ensure that the seed you use is high-quality and as fresh as possible (see below for specialist suppliers). Some gardeners think that “chipping” each seed—removing a tiny bit of the tough outer covering with a sharp knife—improves germination. I don’t do this, but I do soak it in water overnight before “chitting” or pre-sprouting the seeds by placing them inside a tiny closed container or jam jar with its base lined with damp kitchen paper (a method that also divides sweet-pea farmers).
Signs of growth
Within a week after being planted indoors in a warm area (10 to 15 degrees), you should notice signals of growth as each seed starts to sprout a young green shoot and a tiny white root radicle. Once you notice these crucial life-giving indicators, it’s time to rapidly but extremely gently plant each seed into a small, deep pot, root-trainer, or other container filled with high-quality multipurpose compost. Just take careful not to damage the new growth and seed no deeper than 1/2 inch (12 millimeters) before watering gently with a watering can.
The next step, which is where many beginning gardeners struggle, is to resist the urge to coddle your sweet pea plants by placing those newly sown pots or root-trainers on an indoor windowsill where they will unavoidably grow weak, wan, and leggy plants (Instagram is littered with countless proud photos of pathetically invalidish sweet pea seedlings that are the unfortunate results of this sort of helicopter gardening).
Instead, you must adopt the Spartan strategy of “hardening” them through rapid acclimation to colder temperatures. Place the pots or root-trainers somewhere cool and bright as soon as you finish sowing. This may be outside in a sunny, relatively sheltered area beneath the cover of a roof or next to a house wall, or it could be in a bright, unheated glasshouse or cold frame (but make sure to keep these very well ventilated on sunny days). Within one to two weeks, the seedlings should start to show symptoms of emergence.
By covering the pots/root trainers with a fine-mesh netting draped above them (so that the budding seedlings don’t get snagged in it) and tucked in beneath them, you can protect them from mice and birds (who love to steal the seed). In order to protect my pots from slugs, I placed them on an old trestle table with each of its four legs submerged in a pail of water.
The fact that the growth will initially seem to be incredibly gradual shouldn’t worry you. As each seedling starts the crucial process of developing a healthy, robust root system, there is a lot happening below the surface.
Above ground
Maintain the compost moist but not soggy once your seedlings start to emerge above earth, especially in the first several weeks of growth. Many growers advise trimming the developing tip of each young seedling above the first two to three sets of true leaves in order to produce fat, bushy, floriferous plants and promote side-shoot growth. However, if you grow your autumn-sown sweet pea plants as ‘hard’ as you should, they’ll frequently spontaneously create these side-shoots without needing to be nipped out. Therefore, only provide them with temporary additional protection in the form of garden fleece when it is predicted that the temperature will drop below minus 5 degrees. By late March or early April, you’ll have strong, vivacious plants with well-established root systems that you may plant out in their final growing locations.
Give your sweet pea plants a bright place in a weed-free, richly nutritious, moisture-retentive soil that has been amended with lots of organic matter and has been liberally sprinkled with pelleted organic fertilizer. Provide some kind of tall, solid structure that can handle the weight and size of the adult plants, which may easily reach a height of 6-8ft/more than 2m in the correct growing conditions. Keep them very well-watered because they hate it when their roots dry up. Young growth will also need to be tied in.
After that, all that is required to promote the growth of fresh blooms is to select armfuls of those wonderful and delectably scented bloom every couple of days. Which would not be considered a severe burden.