Fragrant Elegance in Bloom: Growing Lathyrus odoratus ‘Flagship’
The deep, velvety tones of Lathyrus odoratus ‘Flagship’ make this climbing annual a true statement in any summer garden. Commonly known as Sweet Pea ‘Flagship’, this cultivar is cherished for its rich violet-blue flowers, classic sweet pea fragrance, and vigorous vining habit. A member of the Fabaceae family, Lathyrus odoratus ‘Flagship’ stands out not only for its color but also for its performance in the garden and vase.
Introducing Lathyrus odoratus ‘Flagship’
Native to southern Italy, Sicily, and parts of the Aegean Islands, Lathyrus odoratus has been cultivated since the 17th century. The ‘Flagship’ cultivar exemplifies the best qualities of the species: a strong, sweet fragrance, eye-catching blooms, and a climbing nature that thrives with proper support.
Developed for cutting and exhibition, Lathyrus odoratus ‘Flagship’ produces large, ruffled flowers in a striking deep blue to purple tone. Each bloom measures approximately 2.5–5 cm (1–2 inches) across and is carried on long, slender stems—ideal for bouquets. Its blossoms cluster along vigorous vines that can grow between 1–2 meters (3 ft 3 in – 6 ft 7 in) in height with adequate support.
Growth Habit and Appearance
Lathyrus odoratus ‘Flagship’ exhibits the classic sweet pea climbing habit. The winged stems bear medium to dark green pinnate leaves arranged in pairs, ending in coiling tendrils that grasp trellises, fences, and other structures. The plant creates a lush vertical display when grown in full sun and well-tended soil.
When Does Lathyrus odoratus ‘Flagship’ Bloom?
Flowering begins in late spring and can continue into early fall, typically from May through September. However, blooms may decline in prolonged high heat or humidity. In cooler climates or where summer evenings remain mild, flowering lasts longer and is more prolific.
Fragrance and Cut Flower Qualities
Like all Lathyrus odoratus cultivars, ‘Flagship’ is highly fragrant. Its perfume is intense, sweet, and nostalgic—a signature trait that makes it an outstanding choice for both gardens and floral arrangements. Long, strong stems ensure the blooms last well in the vase, especially when harvested early in the morning and placed immediately in water.
How to Grow Lathyrus odoratus ‘Flagship’
Light
Plant Lathyrus odoratus ‘Flagship’ in a location with full sun exposure—at least 6 hours of direct sunlight daily. In hotter climates, afternoon shade is beneficial to reduce stress on the plants and prolong blooming.
Soil
Sweet peas thrive in humus-rich, well-drained soils. Amend your garden bed with compost before planting. A neutral to slightly alkaline pH is ideal. Avoid waterlogged soils, which can promote root rot and mildew.
Watering
Regular watering is crucial for optimal growth. Keep the soil evenly moist, delivering about 2.5 cm (1 inch) of water weekly if there is no rainfall. Water at the base of the plant early in the day to prevent fungal problems, and check that the top 2.5 cm (1 inch) of soil stays slightly damp during dry periods.
Fertilizing
Incorporate compost or well-rotted manure before planting. Feed monthly with a fertilizer high in potassium and phosphorus, such as a tomato or bloom booster formula. Avoid high-nitrogen fertilizers, which may encourage lush foliage at the expense of flowers.
Support
As a climbing annual, Lathyrus odoratus ‘Flagship’ or Sweet Pea ‘Flagship’ requires sturdy support. Install trellises, bamboo canes, or netting at planting time. Tie young stems loosely to the support to guide upward growth and prevent tangling.
Spacing
Thin seedlings to 15–20 cm (6–8 inches) apart once they reach 10 cm (4 inches) tall. Adequate spacing ensures airflow and reduces the risk of mildew.
Planting Instructions
When to Plant
In mild climates, sow seeds directly in the ground in autumn for early blooms. In colder zones, sow in late winter or early spring, or start seeds indoors 6–8 weeks before the last frost date.
How to Plant
Scarify the hard seed coats by nicking them or soaking in water for 24 hours before sowing. Plant seeds 2.5 cm (1 inch) deep and 5–7.5 cm (2–3 inches) apart. Germination may take 12–28 days depending on temperature.
Starting Indoors
Use deep pots or root trainers filled with a seed-starting mix. Plant 2–3 seeds per pot, keep the medium moist, and provide bright light. Harden off and transplant outdoors when the soil warms.
Maintenance Tips
Pruning and Pinching
Once seedlings have 4–6 leaves, pinch out the growing tip to encourage bushier plants. Throughout the season, deadhead spent flowers to prevent seed set and extend bloom time. Regular picking of blooms also promotes continuous flowering.
Mulching
Apply a 5–7.5 cm (2–3 inch) layer of mulch around the base of the plants to retain soil moisture, regulate temperature, and suppress weeds. Organic mulch like straw or composted bark works well.
Pests and Diseases
Common Pests
- Aphids: Cluster on new growth. Control by spraying with water or neem oil.
- Thrips: Can scar flowers. Use insecticidal soap if needed.
- Slugs and snails: Damage seedlings and leaves. Protect young plants with copper barriers or slug traps.
- Birds: May pull up seedlings; netting can help.
Common Diseases
- Powdery mildew: Appears in humid or crowded conditions. Improve airflow, avoid wetting foliage, and water early in the day.
- Downy mildew and root rot: Avoid overwatering and poor drainage.
- Enation mosaic virus: Causes distorted foliage and stunted growth. Remove affected plants and control aphid populations.
Propagation
Sweet Pea ‘Flagship’ is propagated by seed. Harvest mature seed pods as they turn brown and dry. Store seeds in a cool, dry place for planting the following season. Note: Seeds should not be consumed, as they are toxic.
Environmental Tolerances
This hardy annual tolerates light frost and prefers cool growing conditions. In regions with hot, humid summers, flowering may slow or stop entirely. Mulching and proper siting can help moderate root temperature and extend bloom.
Toxicity Warning
All parts of the plant, especially seeds, are toxic if ingested. Keep away from children and pets.
Uses in the Garden
Lathyrus odoratus ‘Flagship’ is perfect for:
- Cottage gardens
- Borders and trellises
- Vertical interest in containers
- Cut flower gardens
Its vivid coloring and fragrance make it a standout performer wherever it’s grown.
Final Thoughts on Growing Lathyrus odoratus ‘Flagship’
For gardeners who love vertical interest, fragrance, and timeless charm, Lathyrus odoratus ‘Flagship’ delivers. With the right care—ample sun, rich soil, consistent moisture, and proper support—you’ll enjoy months of velvety violet-blue blooms that dazzle in the garden and in floral arrangements. Though short-lived as an annual, its impact is unforgettable. Sow, support, and snip your way to sweet pea perfection.
Tip: For continuous blooms, sow seeds in succession every few weeks during the spring. And don’t forget—early morning harvested blooms last longest in a vase.
Remember: The seeds are poisonous if eaten. Enjoy their beauty, not their flavor!
