Lathyrus: Planting, Growing and Caring

Botany

Lathyrus or Everlasting Peas comprise around 160 species of perennial or annual herbaceous plants. They are mainly native to temperate regions of the Northern Hemisphere: found in Europe, North America, Asia, as well as North and East Africa, and some temperate regions of South America. They grow particularly in meadows, fallow land, grassy slopes and open woodlands. Many species occur wild in France. Examples include Lathyrus latifolius, Lathyrus vernus and Lathyrus odoratus (sweet pea). The latter is an annual, while most other Lathyrus are perennials.

Lathyrus latifolius: Botanical illustration

Lathyrus belong to the Fabaceae botanical family. The everlasting pea is thus a cousin of beans, peas, clovers… This family includes many ornamental plants such as wisteria, Judas tree, lupin or broom.

Lathyrus often have a climbing habit, attaching themselves to supports using tendrils. Without support, these climbing species adopt a creeping, ground-covering habit. There are also many bushy species or those forming clumps with upright stems. The smallest Lathyrus reach no more than 40 cm tall, while climbing species (notably Lathyrus latifolius) can grow up to 2 m tall.

Perennial peas flower in summer, from June to August or September, except for Lathyrus vernus, which flowers in spring from April to May. It is nicknamed Spring Vetchling.

Everlasting peas produce clusters of papilionaceous flowers, appearing in the leaf axils. Each cluster bears, depending on the species, between 3 and 15 hermaphrodite flowers, 1 to 2 cm long. Very delicate, they closely resemble pea flowers. They consist of five small green sepals and five petals. The petals form an upper banner, two lateral wings and the keel made of two petals. This surrounds the pistil and the 10 stamens.

Flowers of Lathyrus vernus (photo Klaus Selle MA), Lathyrus latifolius ‘White Pearl’, Lathyrus latifolius ‘Red Pearl’, and Lathyrus aureus (photo Franz Xaver)

The flowers come in a beautiful palette of colours, both bright and delicate. They are most often pink, white, mauve or purple, and integrate perfectly into romantic or naturalistic gardens. Lathyrus aureus stands out with its yellow flowers.

Unlike sweet peas (Lathyrus odoratus), perennial pea flowers are not fragrant. However, they are melliferous and attract bees, butterflies and other pollinating insects.

Their flowers integrate very well into rustic-style bouquets. They also add lightness to bouquets alongside larger, more imposing flowers like roses or lilies.

Everlasting peas have beautiful divided foliage, soft green to bluish. The leaves consist of ovate to oblong leaflets. Lathyrus latifolius leaves simply comprise two ovate leaflets and a winged petiole, ending in a branched tendril. Its stems are also winged.

Like other Fabaceae, Lathyrus forms nodules on its roots: a symbiotic association with a bacterium that fixes nitrogen from the air. This allows Lathyrus to grow in poor soils while enriching the soil with nitrogen!

Leaves of Lathyrus latifolius, Lathyrus niger and Lathyrus vernus (photos: Stefan Lefnaer / Franz Xaver)

The fruit of Lathyrus is a flattened pod resembling a bean, which opens at ripeness to release the seeds. These seeds can be harvested for sowing. Although from the same family as peas and beans, Lathyrus pods and seeds are not edible and may cause stomach upset if ingested.

Pods of Lathyrus latifolius (photos: Katrin Schneider / Salicyna / Wouter Hagens)

The main varieties of Lathyrus

Most Popular Varieties

Our Favourite Varieties

Other Varieties to Discover

Lathyrus latifolius Pink Pearl - Broadleaf Sweetpea

This is a beautiful perennial pea with winged stems bearing delicate pale pink flowers in summer. The blue-green leaves consist of two leaflets and are extended by a ramified tendril that allows the plant to cling to a support.

• Flowering time July to October
• Height at maturity 1,80 m

See the product sheet

Lathyrus latifolius White Pearl - Broadleaf Sweetpea

This variety stands out for its pure white flowers. It has been awarded the Award of Garden Merit by the Royal Horticultural Society (RHS).

• Flowering time July to October
• Height at maturity 1,80 m

See the product sheet

Lathyrus vernus

Also called Orobus vernus, the spring vetch bears very beautiful purple-blue flowers in April-May. It forms non-clumping, non-climbing mounds with compound leaves made up of lanceolate leaflets.

• Flowering time May, June
• Height at maturity 40 cm

See the product sheet

 

Lathyrus latifolius Red Pearl - Broadleaf Sweetpea

The ‘Red Pearl’ vetch is a climbing variety that bears carmine pink, almost red flowers in summer.

• Flowering time July to October
• Height at maturity 1,80 m

See the product sheet

Lathyrus aureus

This is a bushy vetch with erect, non-climbing stems that bear clusters of 8 to 25 yellow flowers in late spring, smaller and more delicate than those of Lathyrus latifolius.

• Flowering time June to August
• Height at maturity 40 cm

See the product sheet

 

Lathyrus maritimus - Beach Pea

The sea pea, also known as beach pea, is a creeping species with mauve flowers. As its name suggests, it is a coastal plant that grows naturally along the Normandy coastline in France.

• Flowering time July to September
• Height at maturity 40 cm

See the product sheet

Lathyrus niger

Lathyrus niger produces small pink-purple flowers and leaves made up of numerous small ovate leaflets. It is a rather rare plant in cultivation.

• Flowering time July to September
• Height at maturity 55 cm

See the product sheet

Planting

Where to plant Lathyrus?

Plant Lathyrus in full sun or partial shade, in fresh, fertile soil, rich in humus and well-drained. It is relatively drought-resistant but dislikes waterlogged conditions, which can cause its roots to rot. If your soil tends to retain water, don’t hesitate to add coarse sand or gravel, or plant on a mound to improve drainage. Lathyrus latifolius thrives in chalky soils but is fairly tolerant of pH levels.

Remember to provide a support for Lathyrus latifolius to climb onto: trellis, stakes, wire mesh… In the wild, the everlasting pea often climbs nearby bushes and plants. Without support, it will spread and behave like a creeping ground cover. The species Lathyrus vernus, Lathyrus niger and Lathyrus maritimus are not climbing plants, so they don’t require staking.

Lathyrus maritimus is an ideal plant for coastal gardens. It grows naturally in sandy or stony, poor and well-drained soils. With its long creeping stems, it helps stabilise dunes and unstable soils.

When to plant?

Plant Lathyrus in spring or autumn, avoiding periods of frost or extreme heat.

How to plant?

If planting several young plants together, space them at least 30 cm apart.

1. Soak the Lathyrus in a basin of water to rehydrate the root ball.
2. Dig a planting hole two to three times the size of the root ball.
3. Add some compost and, if needed, sand or gravel (for drainage), mixing them into the soil.
4. Place the Lathyrus in the planting hole.
5. Backfill with soil and lightly firm it down.
6. Water generously.
7. You can apply organic mulch around the base to retain soil moisture.
8. If planting a climbing species (e.g., Lathyrus latifolius), install a support and gently guide its shoots onto it. The Lathyrus will then climb independently using its tendrils.

Spring vetchling, Lathyrus vernus

Maintenance

The everlasting pea is an easy-going plant, requiring very little maintenance. Once established, Lathyrus latifolius is quite drought-resistant. However, to encourage abundant flowering, water regularly in spring and summer, especially during dry spells, but avoid excess moisture which could cause the roots to rot (always allow the substrate to dry out between waterings). Similarly, when watering, avoid wetting the foliage. Don’t hesitate to mulch the soil around the base of the Lathyrus to keep the soil cool for longer and to suppress weed growth. Additionally, as the mulch decomposes, it will enrich the soil by adding organic matter.

Lathyrus will appreciate a well-rotted compost application in early spring. This will enrich the soil and encourage flowering. If grown in a large pot or container, you can apply liquid fertiliser every two weeks in spring and summer.

In spring, pinch back the stems to encourage branching, resulting in denser and bushier young plants.

In summer, we recommend removing faded flowers. This will encourage the plant to produce new blooms. However, if you wish to propagate the plant, leave a few faded flowers on the young plant to collect the seeds from the pods.

Snails and slugs enjoy nibbling on the leaves and young shoots of Lathyrus. To protect your young plants, you can use slug pellets or create a slug trap. Feel free to check out our guide “Slugs: 7 Effective and Natural Ways to Control Them”.

Lathyrus can sometimes be attacked by aphids, which pierce the plant to feed on the sap, weakening it. To get rid of them, you can spray with black soap (diluted at a rate of 15 to 30 g per litre of water) or, as a last resort, a pyrethrum-based insecticidal spray. Lathyrus can also be affected by downy mildew or powdery mildew, fungal diseases caused by mould.

Propagation

The best way to propagate Lathyrus is by sowing. It is also possible to divide young plants.

Sowing

In open ground

You can sow sweet pea seeds in autumn (September-October) or in early spring.

1. Soak the seeds in lukewarm water for 24 hours.
2. Prepare the soil: loosen the soil to a depth of about 10 cm, remove weeds and larger stones, and level the soil to create a fine, flat seedbed.
3. Sow the seeds in clusters (groups of 2 to 3 seeds), spaced about 30 cm apart.
4. Cover them with a layer of soil (2 to 3 cm thick).
5. Water gently with a fine spray.
6. Continue to water regularly until germination, but avoid overwatering.

In pots

We recommend sowing sweet peas in pots in late winter or early spring (March-April).

1. Soak the seeds in lukewarm water for 24 hours.
2. Prepare a pot with compost.
3. Sow the seeds.
4. Cover them with 2 to 3 cm of compost, then lightly firm down.
5. Water gently with a fine spray.
6. Place the pot in a sheltered, bright spot, out of direct sunlight.
7. Keep the substrate slightly moist until germination, but avoid overwatering to prevent damping off.
8. Once the seedlings are large enough to handle, transplant them into individual pots.

Association

The Lathyrus will easily find its place in a naturalistic garden. It will be perfect to accompany the small white or pink, butterfly-shaped flowers of Gaura lindheimeri. Plant alongside them penstemons, Buenos Aires vervain, and yarrows. Also enjoy the delicate flowering of knautias and scabious. Incorporate some ornamental grasses, such as Pennisetums and Stipas: their fine foliage and light spikes will give your garden a wild meadow feel. Don’t forget wildflowers like poppies and cornflowers!

Discover our selection of the most beautiful perennial plants for naturalistic gardens.

Sweet peas blend beautifully into a rustic, naturalistic garden! Penstemon ‘Souvenir d’Adrien Regnier’, Lathyrus latifolius (photo Forest and Kim Starr), Gaura lindheimeri ‘Siskiyou Pink’, Scabiosa atropurpurea ‘Scarlett’ (photo Annie’s Annuals), cornflowers and poppies

Pink or white-flowered sweet peas, such as Lathyrus latifolius ‘Pink Pearl’ or ‘White Pearl’, will fit perfectly into a romantic garden. They will complement the flowering of roses, clematis, lilies, and foxgloves. For bushes, opt for the stunning blooms of Deutzia setchuenensis ‘Corymbiflora’ and Ceanothus pallidus ‘Marie Simon’. Plant alongside them airy, delicate blooms like baby’s breath (Gypsophila paniculata) and gaura. Also incorporate silver foliage, such as Stachys byzantina or artemisias. They will enhance the soft, delicate feel of the border and beautifully complement white and pink flowers!

Discover our “Romantic Garden” inspiration page

You can create a lovely romantic atmosphere with white or pink-flowered Lathyrus! Clematis ‘Ville de Lyon’, David Austin Rose ‘Darcey Bussel’, Deutzia setchuenensis ‘Corymbiflora’, Lathyrus latifolius ‘White Pearl’, Artemisia stelleriana ‘Silver Brocade’, and Dianthus plumarius ‘Scent First Tickled Pink’

Lathyrus maritimus, on the other hand, is perfect for a coastal garden. Its summer flowering will complement that of Sea Holly (Eryngium maritimum), Delosperma cooperi, agapanthus, and Sea Thrift, Armeria maritima. Plant alongside them agaves for their striking structure and exotic style! Also discover Anthyllis barba-jovis, a superb Mediterranean bush with finely cut, silvery-grey foliage.

Pair Lathyrus vernus with spring-flowering plants. Consider, for example, spring bulbs: tulips, daffodils, grape hyacinths, fritillaries… You can also include Bleeding Hearts (Dicentra spectabilis), which offer charming white or pink heart-shaped flowers.