Sweet pea (Lathyrus odoratus)
Lathyrus odoratus, the Sweet pea, is a fragrant annual vine offering showy blooms from May to July. Ideal for cool summers.
Complete Plant Information
Overview
The Sweet pea (Lathyrus odoratus) is highly prized by gardeners for its intensely fragrant flowers, a characteristic highlighted by its specific epithet, odoratus. This annual vine offers vibrant color and delicate structure, making it a classic choice for cottage gardens and cutting arrangements. Gardeners seeking reliable, sweetly scented blooms must pay close attention to its cultural needs, as this plant thrives best in cooler conditions.
As a vigorous climber, the Lathyrus odoratus can reach impressive heights of up to 8 feet, though it may also sprawl into a bushy mound if left unsupported. Its ability to produce masses of showy, keeled flowers from late spring into mid-summer makes it a rewarding plant to grow from seed. Success with the Sweet pea often relies on providing a support structure and managing the transition into hot summer weather.
This legume is invaluable for adding vertical interest and intoxicating perfume to the landscape. While species plants traditionally feature purple flowers, modern cultivars of Sweet pea offer an extensive palette, excluding only true yellow. Whether trained upward or allowed to ramble, Lathyrus odoratus brings ephemeral beauty to seasonal plantings.
Fast Facts
- Plant Family: Fabaceae
- Plant Type: Annual
- Native Range: Crete, Italy, Sicily
- Hardiness Zones: USDA Zones 2-11
- Size at Maturity:
- Height: 3-8 ft
- Spread: 2-3 ft
- Bloom Time: May to July
- Bloom Description: Cultivars in all colors except yellow
- Sun Exposure: Full sun
- Water Needs: Medium
- Maintenance Level: Medium
How to Grow
Planting Sweet pea successfully begins with cool soil. Aim to start seeds indoors 6–8 weeks before your average last spring frost date, especially if you live in areas expecting rapid summer heat, to maximize bloom time. Alternatively, in warmer winter regions, fall sowing provides winter and spring flowers. The ideal location requires full sun and rich, humusy, well-drained soil with medium moisture retention. Incorporate compost prior to planting to build soil structure.
Ongoing care centers around consistent moisture and avoiding the heat stress that causes rapid decline. Provide even moisture throughout the growing season, ensuring you avoid overhead watering when possible to minimize humidity around the foliage. Regular feeding with fertilizer will support continuous blooming. As temperatures rise, the performance of Lathyrus odoratus will diminish.
For climbing varieties, a trellis, net, or sturdy stakes are essential support structures. Deadhead spent flowers diligently to encourage the plant to put energy into producing more blooms rather than setting seed. A crucial cultural note is to avoid planting sweet peas in the same location in consecutive years to help mitigate potential soil-borne issues.Mulching the soil can help keep root zones cool during early summer heat waves.
Landscape Uses
The versatility of the Sweet pea allows it to enhance several garden styles. They are perfect for borders, adding height and fragrance near walkways where their scent can be easily appreciated, or serving as the backbone of a classic cottage garden design. Ensure that climbing types have adequate vertical support to twine upon, while bushy varieties can sprawl attractively at the edge of a bed.
Even when grown as climbers, they are excellent companions for structure-loving plants or short annuals that can handle similar sun and moisture requirements. Consider pairing them with mid-season bloomers or structural herbs that offer strong visual anchors once the Lathyrus odoratus begins to fade in high summer.
Don’t overlook containers; dwarf or semi-trailing cultivars work well for patio displays, spilling over the edges. Whether you choose to sprawl them along the ground or twine them vertically on supports, the Sweet pea offers vibrant seasonal color and unmatched fragrance wherever they are placed.
Standout Features
Flower Qualities
- Showy
- Fragrant
Noteworthy Characteristics
Lathyrus odoratus, commonly called sweet pea, is a bushy or climbing annual that features highly fragrant flowers (odoratus meaning fragrant) on winged stems clad with medium to dark green leaflets in pairs. Stems end in tendrils which enable plants to climb, allowing the vine structure to reach up to 6-8’ in a single season, although unsupported growth is typically a bushy mound reaching about 2.5’ tall. While species plants exhibit purple flowers, numerous cultivars are available in pink, red, blue, lavender, white, and bicolors.
Tolerances
Potential Problems
This plant generally avoids severe insect or disease issues, which is excellent news for gardeners. However, young Sweet pea seedlings are particularly attractive to slugs and snails; use appropriate barriers or baits early in the season for protection. Aphids are another potential visitor to watch for. It is important to remember that while related to edible peas (Pisum sativum), all parts of the sweet pea fruits are considered inedible and poisonous if ingested by humans.
Frequently Asked Questions
What hardiness zones is Sweet pea suitable for?
Lathyrus odoratus is remarkably adaptable, thriving in USDA Zones 2 through 11.
How large does Sweet pea grow?
This annual typically reaches a height between 3 and 8 feet, with a spread of 2 to 3 feet when given support for climbing.
What sun exposure does Sweet pea need?
The ideal requirement for the Lathyrus odoratus is full sun, though it can tolerate some light shade, especially as summer begins to heat up.
When does Sweet pea bloom?
You can expect blooms from May through July, with cultivars offering nearly every color imaginable, excluding true yellow.
Conclusion
The exquisite fragrance and vibrant, showy blooms of the Sweet pea (Lathyrus odoratus) make it a mandatory addition to any seasonal flower border. Its relatively medium maintenance is easily managed when you focus on providing cool soil conditions and consistent moisture throughout the spring growing season. Check your local frost dates and plan to start your seeds early to ensure a spectacular, fragrant display of Lathyrus odoratus this year.
Companion Planting
When planning your garden layout around the Sweet pea, focus on companions that appreciate similar soil richness and can handle similar watering schedules. Annuals that fill in the lower space while the vines climb are excellent companions. Consider shorter, sun-loving flowers like low-growing snapdragons or petunias to provide continuous color below the taller vines, especially as the Lathyrus odoratus begins to slow down in the heat.
Another successful pairing strategy involves planting companions that offer structural contrast. Because the sweet pea vine is delicate and twining, plants with a more robust habit, such as calendula or certain dill varieties, can provide a sturdy backdrop or frame their climbing efforts without competing aggressively for root space, provided soil health remains rich and well-drained.
Seasonal Care Calendar
Gardeners should adapt their care for Lathyrus odoratus based on regional temperature fluctuations. Spring preparation is crucial; ensure the growing area is amended with compost before sowing or transplanting seedlings. Once growth begins, maintain medium watering levels, focusing on the base of the plant to keep the roots cool.
As summer approaches and temperatures climb, monitor closely for signs of decline indicative of heat stress. If hot, humid weather sets in, increase watering slightly to compensate for transpiration but continue to avoid overhead wetting. The single most important task during late spring is consistent deadheading of spent flowers to maximize the longevity of the bloom period before the plant finally succumbs to summer heat in warmer climates.
