Flat Pea plants can grow purple, pink, or white flowers. These plants are good for fertilizing disturbed soil. Their ability to grow in disrupted soil makes them good for erosion control. If the seeds are deep-rooted as much as 30 cm then they can grow up to 2 m tall.
I. Appearance and Characteristics
Lathyrus sylvestris, the flat pea or narrow-leaved everlasting-pea, is a species of flowering plant in the pea and bean family Fabaceae.
The narrow-leaved everlasting-pea is native to parts of Africa, Europe and Asia. Its natural habitat is forest edges, sparse broad-leaved hillside forests, dry hillside meadows, hedgerows, embankments and waste ground. It uses its tendrils to scramble over plants, shrubs and the lower branches of trees.
The narrow-leaved everlasting-pea is a perennial plant which can grow 200 cm (79 in) by climbing with its tendrils. Without any support it can reach about 75 cm (30 in) tall. The stem is floppy and flat with wide wings. The leaves are alternate with short winged stalks and stipules. The leaf blades are pinnate with a single pair of narrow lanceolate leaflets with entire margins and three tendrils. The inflorescence has a long stem and three to ten pinkish-red flowers. These have five sepals and five petals and are irregular. The uppermost petal is known as the “standard”, the lateral two as the “wings” and the lowest two are joined to form the “keel”. There are ten stamens and a single carpel. The fruit is a long pod containing five to fifteen seeds.
II. How to Grow and Care
Flat pea is a robust perennial plant well-suited for growth in temperate regions. Key care points include ensuring adequate support structures for its climbing habit and managing its invasive potential by controlling its spread. With these considerations in mind, flat pea is generally an easy plant to care for, tolerating a variety of soil conditions and withstanding occasional neglect.
Sunlight
Flat pea thrives best under full sun conditions, receiving sunlight for at least 6-8 hours per day, which is critical for its vigorous growth and optimal health. Although flat pea has a moderate tolerance for partial sun, where it can still perform well, it is important to note that insufficient light may lead to leggier growth and reduced flowering. Due to the plant’s adaptability, in partial sunlight conditions, flat pea may adjust by extending its stems towards the light source. Recommended for outdoor environments, flat pea should be positioned in open areas that receive ample light throughout the day without consistent shadowing from larger plants or structures.
Temperature
Flat pea likes a place that is warm in winters and cool in summers, with sufficient sunlight. It doesn’t thrive well in extreme heat and is slightly tolerant of cold conditions. Best growing temperatures are between 5 to 20 ℃. Temperatures above 20 ℃ affect its growth and even cause withering and death. As an annual plant, sweet peas can be planted in almost all zones.
Flat pea does not require much water and is fairly resistant to drought. If you water it regularly, it will grow better.
Watering
Originating from temperate regions, flat pea is accustomed to moderate moisture levels and can endure short periods of drought. Its preference for well-drained soil aligns with its ability to tolerate occasional dryness. For optimal growth, flat pea should be watered every week, maintaining a balance that prevents both over-saturation and dehydration. As an outdoor plant often found in gardens, flat pea’s resilience is complemented by its adaptability to rain patterns, making it a versatile addition to various climate zones.
Soil
Flat pea prefers fertile soils that are well-drained and rich in nutrients. Mix perlite with general cultivation soil. Akadama and humus can be mixed in a ratio of 8: 2. It grows well in soil with a pH of 6-7.5. Soil should be prepared 2 weeks before planting. Generally, sulfur or iron sulfate is used to lower the pH value of soil and lime is used to increase it.
When planting, mix compost and bone meal in advance to increase soil nutrients. To prevent poor plant growth and disease, avoid growing in moist and dark places, or on plots that grew legumes last year.
Fertilizing
For flat pea, a balanced fertilizer (like a 10-10-10 mix) bolsters growth and flowering. Apply in early spring and repeat every 4-6 weeks until late summer, adhering to package directions; typically, a tablespoon per plant suffices. Benefiting flat pea, fertilization boosts health and yields. Seasonal growth stages dictate varying nutrient needs; less is more during dormancy. Avoid root burn by watering before and after fertilizing. Wearing gloves, work fertilizer into soil gently, avoiding foliage contact. Effective fertilization hinges on using correct types and quantities, enhancing flat pea’s vigor.
Planting Instructions
The optimum temperature for germination of flat pea is between 15 to 20 ℃. Soak seeds in warm water for 24 hours before planting, or use a knife to scratch the surface of each seed, to promote seed germination. When sowing, keep 10 to 15 cm between seeds and cover with 1 cm of soil.
In frost-free areas, the seeds of flat pea can be buried directly in the ground when the weather turns cold in the late fall. In colder areas, it is best to sow indoors to avoid damage due to low temperatures. Even in areas with cool summers, plant in early spring to prevent the seedlings from the high temperatures in midsummer.
The root system of flat pea is straight and well developed. Avoid transplanting after sowing. If you want to transplant seedlings, it is best to dig a hole at enough depth to hold all roots and the soil that is clinging to the roots. Flower pots need to be at least 15 cm deep. After the seedlings grow up, use bamboo poles, stakes, trellis, etc. to provide support and guide its climbing growth.
Pruning
When the branches of flat pea are 15 cm or longer, pruning is recommended to produce more lateral branches, growing more flowers. Cutting off the withered flowers (deadheading) can save nutrients and promote more flower buds. If you want to cultivate strong branches, choose the healthiest, strongest twigs and cut off other tendrils or lateral branches. This method makes flat pea concentrate nutrients on blooming and avoids unnecessary nutrient consumption.
Stake bamboo poles, wooden sticks, net racks or other supports 2 m tall or more beside the plant. This allows flat pea to climb. As a vine, flat pea can climb to 1 to 2 m in one season. Without support, it will grow into a thicket of about 80 cm high.
Propagation
Flat pea is a perennial species prominent for its climbing habit and showy flowers. For successful propagation, sowing its seeds directly in well-draining soil is effective. To enhance germination, a period of cold stratification may be beneficial. Carefully embed seeds just below the soil surface; moisture should be consistently maintained without causing waterlogging. Once established, flat pea can self-seed, making it a low-maintenance option for expanding your garden’s floral diversity.
Transplanting
Transplant flat pea in the rejuvenating warmth from mid to late spring, ensuring a location with adequate sunlight and well-drained soil for optimal growth. A friendly tip: choose a spot that mimics its natural environment for seamless transitioning.
III. Uses and Benefits
This plant is sometimes used to control erosion and for this purpose it is generally planted along with a grass species. It can do well in highly disturbed habitats. There is a cultivar called ‘Lathco’.
IV. Harvesting and Storage
It is time to harvest when the flowers fully bloom. The best time to harvest flowers is early in the morning. The second choice is on a cool night. Bring a bucket of water when harvesting. Insert cut branches of flowers into water immediately to avoid water loss. When the flowers cannot be immersed in water, they should be as close to the water level as possible so that the stems are in full contact with the water.
You can also cut the stem in the water, for the reason that air may enter the stem and block water transmission when cutting in the air. Adding floral preservatives to the vase and changing the water every two days is also advised.
