Sweet Pea (Lathyrus odoratus) is a flowering climbing plant native to Sicily, southern Italy, and the Aegean Islands. It belongs to the legume family Fabaceae and was first formally described by botanist Francisco Cupani in 1695. The plant became widely cultivated in England during the 18th and 19th centuries, where breeders developed the rich variety of colors we see today.
Sweet Peas are beloved for their delicate, ruffled, butterfly-like blooms that come in an extraordinary range of colors — from pure white and soft pastels to deep purples, vivid pinks, reds, and bi-colored varieties. The vines can grow anywhere from 30 cm (dwarf types) to over 2 meters tall, with tendrils that help them climb supports. The foliage is a soft, grey-green and pairs beautifully with the jewel-toned flowers.
One of the most celebrated qualities of Sweet Peas is their intoxicating perfume. The scent is sweet, warm, and slightly honeylike — considered one of the finest natural fragrances in the floral world. Interestingly, many modern varieties have been bred for larger, more colorful flowers at the expense of scent, so older heirloom varieties like ‘Cupani’ and ‘Matucana’ tend to be the most fragrant.
Sweet Peas carry rich symbolism across cultures. They traditionally represent blissful pleasure, delicate beauty, and departure — often given as a farewell gift or to convey gratitude for a lovely time. In the Victorian language of flowers, gifting Sweet Peas was a gracious gesture of thanks. They are also the birth flower for the month of April.
Sweet Peas are primarily grown as ornamental garden plants and are exceptionally popular as cut flowers, prized for their fragrance and soft beauty in bouquets and floral arrangements. They are a staple in cottage gardens and are widely used by florists for wedding and event work. Despite their name, they are not edible — all parts of the plant are toxic if consumed.
Sweet Peas are cool-season annuals, meaning they thrive in the mild temperatures of spring and early summer. They struggle in intense heat and will typically die back once temperatures rise consistently above 27°C (80°F). In warmer parts of the United States — such as Florida and California — they do best sown in autumn or winter for a spring bloom, taking advantage of the milder months before summer heat sets in. In cooler northern states, spring sowing as soon as the soil can be worked is the ideal approach.
How to Grow & Care for Sweet Peas
- Choose the right time to sow. Sweet Peas prefer cool growing conditions. Sow seeds in late autumn or early spring (or year-round at higher elevations in warm climates like Kenya’s highlands). Avoid sowing when heat is intense, as they bolt and stop flowering quickly.
- Soak seeds before planting. Sweet Pea seeds have a hard coat. Soak them in water for 12–24 hours before sowing to soften the seed coat and encourage faster, more uniform germination.
- Sow at the right depth. Plant seeds about 2–3 cm (1 inch) deep in well-prepared soil or seed-starting compost. Space seeds roughly 10–15 cm apart if sowing directly in the ground.
- Provide well-draining, fertile soil. Sweet Peas thrive in deep, rich, well-draining soil with a slightly alkaline to neutral pH (around 7.0–7.5). Dig in plenty of well-rotted compost or manure before planting to improve soil structure and fertility.
- Give them plenty of sunlight. Choose a spot that receives at least 6–8 hours of full sun daily. While they can tolerate light afternoon shade (especially in warmer climates), insufficient light leads to weak, leggy plants with fewer blooms.
- Install support structures early. Sweet Peas are climbers and must have something to grip — a trellis, wire mesh, bamboo canes, or a garden obelisk. Put supports in place at the time of planting so the young tendrils can begin climbing immediately without being disturbed later.
- Water consistently and deeply. Keep the soil evenly moist but never waterlogged. Deep, consistent watering is preferable to shallow, frequent watering, as it encourages roots to grow deep. Drought stress causes the plants to set seed prematurely and stop flowering.
- Mulch around the base. Apply a layer of organic mulch (straw, compost, or bark) around the base of the plants to retain soil moisture, regulate root temperature, and suppress weeds. Keep mulch away from the stems to prevent rot.
- Feed regularly for abundant blooms. Once plants begin to flower, feed every 10–14 days with a high-potassium liquid fertilizer (such as a tomato feed). Avoid over-feeding with nitrogen, which promotes leafy growth at the expense of flowers.
- Deadhead flowers religiously. This is perhaps the most important care tip. Remove spent blooms as soon as they fade — before seed pods can form. Once Sweet Peas begin setting seed, they interpret their job as done and flowering slows or stops entirely. Regular deadheading keeps them blooming for weeks longer.
- Pinch out growing tips when young. When seedlings reach about 10–15 cm tall and have developed two or three pairs of leaves, pinch out the growing tip. This encourages bushy, multi-stemmed growth and ultimately produces more flowers than a single main shoot would.
- Watch for pests. Aphids are the most common pest on Sweet Peas, clustering on soft new growth and buds. Check plants regularly and treat infestations early with insecticidal soap, neem oil, or a strong jet of water. Slugs and snails can also damage young seedlings, especially at night.
- Manage powdery mildew. Poor air circulation and overwatering can lead to powdery mildew, a fungal disease that coats leaves in a white powder. Space plants adequately, avoid wetting the foliage, and treat early signs with a diluted baking soda spray or a suitable fungicide.
- Avoid root disturbance. Sweet Peas have sensitive, deep roots and dislike being transplanted once established. If starting seeds indoors, use biodegradable pots (like cardboard tubes or peat pots) that can be planted directly into the ground without disturbing the roots.
- Harvest cut flowers regularly. If growing Sweet Peas for cut flowers, harvest stems frequently — ideally every 2–3 days — cutting them when the lowest bud on the stem is just beginning to open. Like deadheading, regular harvesting signals the plant to keep producing more blooms.
- Allow a few plants to go to seed at the end of the season. At the close of the growing season, let a handful of seed pods fully ripen and dry on the vine. Collect and store the seeds in a cool, dry place. Sweet Pea seeds remain viable for several years and can be saved for the following season’s planting.