Sweet Pea.

At a glance

Care level

Easy

Plant type

Annual vine

Light

Full sun

Indoor light

direct

Water

Every 2 to 3 days

Mature size

Vining, can reach up to 2.5 meters (8 feet)

Growth rate

fast

Hardiness

USDA 2 to 11

Bloom time

Late spring to early summer

Care

Provide support for climbing and ensure good air circulation to prevent powdery mildew. Deadhead spent blooms regularly to encourage more flowering. They thrive in cooler temperatures, so plant them when the weather is mild.

Watering

Keep soil consistently moist but not waterlogged, especially during flowering.

Feeding

Feed with a balanced fertilizer, low in nitrogen, every two weeks once established.

Pruning

Pinch back young plants to encourage bushier growth; deadhead regularly.

Repotting

Typically grown from seed sown directly or started indoors; not typically repotted after initial germination.

Soil

Well-draining, fertile loam

Soil pH

6.5 - 7.5

Temperature

7 to 24°C

Humidity

40 to 70%

Safety

People

All parts of the sweet pea plant, especially the seeds, are toxic if eaten and can cause nausea, vomiting, dizziness, and other adverse effects.

Children

Sweet pea seeds are toxic if ingested, so keep them away from small children who might be tempted to taste them.

Edibility

The seeds of sweet peas are toxic if ingested.

How to identify it

• Vining habit
• Sweetly fragrant flowers
• Pea-like pods
• Compound leaves
• Delicate, butterfly-shaped blossoms

Height

0.6 to 2.5m

Spread

0.3 to 0.6m

Leaves

Green, deciduous

Flowers

Pink, Purple, Red, Blue, White, Bicolor, 2.5 to 5cm

Common problems

• Aphids — These small insects can cluster on new growth and undersides of leaves, weakening the plant and potentially spreading disease.
• Powdery Mildew — A common fungal disease that appears as white, powdery spots on leaves and stems, often in humid conditions.
• Root Rot — Caused by overwatering or poorly draining soil, this fungal disease can lead to yellowing leaves and plant death.
• Slugs and Snails — These gastropods can chew holes in the leaves and flowers, especially during damp weather.

Growing it

Propagation

Seed

When to plant

Spring, Fall

When planting sweet peas, consider companion plants that help deter pests or improve soil conditions without competing too heavily for nutrients.

Grows well with

• Nasturtium — Nasturtiums can act as a trap crop for aphids, drawing them away from your sweet peas.
• Marigold — Marigolds are thought to deter certain soil nematodes and some insect pests with their fragrance.
• Radish — Radishes can help break up the soil and are sometimes planted nearby to attract flea beetles away from more valuable crops.

Keep away from

• Fava Bean — Both sweet peas and fava beans are legumes and can compete for similar nutrients in the soil, potentially impacting each other's growth.
• Garden Pea — Like fava beans, garden peas are also legumes and can compete for soil nutrients, and they may also share susceptibility to some of the same diseases.

Similar species

• Everlasting Pea — This species is a vigorous perennial climber with similar vining habits but typically lacks the strong fragrance and diverse colors of sweet peas.
• Wild Sweet Pea — A native vining plant that produces smaller, less colorful flowers and usually has a less intense fragrance compared to the cultivated sweet pea.

Science

Family

Fabaceae

Genus

Lathyrus

Order

Fabales

Class

Magnoliopsida

Native range

Southern Italy and Sicily.

Conservation

Not of conservation concern.

In their native habitat, sweet peas grow in rocky, coastal areas and scramble through other vegetation for support.

Value to wildlife

nectar source

Pollinators

bees, butterflies, moths

Uses

ornamental, cut flowers

Taxonomy resolved against GBIF.

Questions people ask

How much sun do sweet peas need?

Sweet peas prefer full sun but can tolerate partial shade, especially in hotter climates.

What kind of soil is best for sweet peas?

They thrive in well-drained, fertile soil rich in organic matter.

When is the best time to plant sweet peas?

You can sow sweet pea seeds in early spring or fall, depending on your climate; they prefer cooler temperatures.

Do sweet peas need support?

Yes, as climbing plants, they need trellises, netting, or stakes to grow upwards.

How often should I water sweet peas?

Keep the soil consistently moist, especially during flowering, but avoid waterlogged conditions.

Can I grow sweet peas in pots?

Yes, sweet peas can be grown in containers, provided they are large enough and have good drainage.

Where the name comes from

The genus name 'Lathyrus' comes from the Greek word 'lathyros', meaning 'a pulse' or 'pea'. The specific epithet 'odoratus' is Latin for 'fragrant', referring to the sweet scent of its flowers.

Good to know

• The common name 'sweet pea' was coined by Jane Austen's sister, Cassandra.
• Sweet peas were first cultivated in Italy in the 17th century.
• The scent of sweet peas can vary greatly depending on the cultivar.
• They are climbing plants that can grow up to 6-7 feet tall with support.