Perennial sweet pea aka Lathyrus latifolius [LAY-thy-russ lat-ee-FOH-lee-us] is a rhizomatous herbaceous perennial. Known as:
- Perennial pea
- Wild sweet pea
- Everlasting pea
The plant is a member of the Fabaceae (fab-AY-see-ee) family and a native of the Mediterranean (northern Africa and southern Europe).
The genus name comes from the Greek word for pulse or pea Lathyrus. Its specific species latifolius means “broad-leaved.”
Perennial Sweet Pea Quick Care Tips
- Botanical Tips: Botanical Name: Lathyrus Latifolius
- Common Name(s): Sweet Pea
- Synonyms: Everlasting Pea, Perennial Pea
- Family & Origin: Fabaceae family, native to Mediterranean (northern Africa and southern Europe).
- Growability: Easy to grow
- Grow Zone: 3-8
- Size: Can grows to a height of 6′ to 9′ feet with a spread of 3′ to 6′ feet.
- Flowering: Blooms in summer with pink, white, or purple flowers
- Light: Requires about 6 hours or more sunlight daily.
- Humidity: Not picky about humidity
- Temperature: Can tolerate a range of temperatures that do not fall below 50° degrees Fahrenheit.
- Soil: Well-draining soil
- Water: Regular watering, but avoid overwatering
- Fertilizer: Fertilize in spring with a balanced fertilizer
- Pests & Diseases: Can be susceptible to powdery mildew and aphids
- Propagation: Can be propagated by seed or division
- Plant Uses: Great for trellises, fences, and borders. Can also be used as a cut flower.
Perennial Sweet Pea Flower Care
Size and Growth
Everlasting pea climber has a trailing and climbing habit and grows to a height of 6′ to 9′ feet with a spread of 3′ to 6′ feet.
When left to its own devices with nothing to climb, the plant will ramble as far as it can grow as a groundcover approximately 4″ to 8″ inches high. When it has support, it will climb to a height of 6′ to 9′ feet.
Flowering and Fragrance
The perennial sweet pea blooms from late spring or early summer (June through late September), producing great masses of scentless blossoms.
Its flowers borne on winged stems are impressively showy in pastel shades of white, pinkish purple, and rose.
Even though the blossoms are not fragrant, they are attractive to butterflies, hummingbirds, bees, and other pollinators.
The perennial sweet pea vine produces abundant flowers throughout the summer and into the fall.
To encourage more blooms, be sure to deadhead spent flowers. If you don’t deadhead, the plant will produce seedpods that resemble those of an edible pea plant.
Take care not to eat these “peas,” though. They are quite poisonous. The plant’s leaves are broad, grayish-green, and about 3″ inches long.
Light and Temperature
Perennial sweet pea is a hardy plant thriving in full sun in USDA hardiness zones 3 through 8. It requires about 6 hours or more sunlight daily. However, afternoon shade can be as beneficial.
While sweet pea plants can tolerate some light shade, it does best in full sun with night temperatures that do not fall below 50° degrees Fahrenheit during the growing season.
Watering and Feeding
It’s best to keep the soil evenly moist throughout the growing season. Use ground watering techniques (soaker hoses or drip irrigation) to avoid problems with fungal infection.
Fertilizer is not necessary if you amend the soil with ample amounts of compost and aged manure at planting time.
Once a perennial sweet pea patch gets established, supplement the soil with a fertilizer high in potash. Avoid using high nitrogen-rich fertilizers as this promotes excessive top growth.
You can also use organic fertilizers like fish emulsion. Remember to follow the label directions.
Soil and Transplanting
It is easy to grow pea perennial in almost any soil type, but it thrives in rich soil. The perennial sweet pea also do quite well in the soil at nearly every pH level. They seem not to mind clay, sand, or loam.
However, you may amend your soil with organic matter to improve it into fertile soil.
The plant does best in average, well-draining soil with a moderate amount of moisture and humus. Amend with aged manure and compost.
Grooming and Maintenance
The Perennial sweet pea requires regular maintenance.
Vigorously cut pea Lathyrus latifolius back to prevent it from growing and getting out of control. The pruning will encourage more bushy growth and more blossoms.
Deadhead sweet pea flowers throughout the growing season to get more blooms. In addition, snip the seed pods if you see any of this forming. Regular deadheading will also prevent the plant from forming seed pods.
Moreover, stake the plant and provide a trellis or other climbing structure to prevent toppling over using organic material like garden twine or support rings.
At the beginning of the growing season, in early spring, cut the plants all the way to the ground. Next, remove dead growth from the plant climbing structure or trellis.
In the autumn, cut the plant back to ground level in the fall. You can also pinch the shoot tips to encourage bushy growth.
How To Propagate Perennial Lathyrus Latifolius
Everlasting sweet peas are both self-seeding and spread via rhizomes, so propagation is quite easy.
It’s important to note that seed coats can be hard. So you should chip or nip the sweet pea seeds before sowing. You can also soak it in warm water to soften it.
Sow sweet pea seeds in the soil above 50° degrees Fahrenheit in late winter. If you plan to have sweet peas climb, dig a trench about an inch deep and a foot away from the trellis you intend the plant to climb.
Plant your sweet pea seeds a couple of inches apart.
To encourage germination, crack the sweet pea seed slightly using a toenail clipper or a file. Be careful not to cut too deeply, or you will damage the flower seed.
Provide a thorough watering at the time of planting. Water every two or three days after that. Be careful not to overdo it, but keep the soil moist. The seed should sprout within 3 to 4 weeks.
Thin the sweet pea seedlings to a distance of about a foot apart.
Perennial Pea Pests Or Diseases
This hardy, rambunctious plant has very few problems.
If kept in a damp setting with low air circulation and not enough sunlight, sweet pea plants may experience problems with snails, slugs, fungal related problems such as:
- Leaf spot
- Black root rot
- Rust
- Gray mold
- Mildew
Remember, a perennial pea can be prone to powdery mildew and other diseases under stressful conditions.
To prevent these problems, choose a bright, airy location with well-draining soil for your sweet peas to dwell.
Avoid overwatering, and remember not to use a sprinkler or other overhead watering method.
The perennial sweet pea is invasive, toxic, and deer resistant.
Suggested Use For Perennial Pea
This showy, drought-resistant plant makes an excellent ground cover, but you must not let it get away from you.
It can be quite invasive in many parts of the United States and Canada.
Everlasting wild sweet pea has been popular in North America since early in the 18th century and is said to have been grown by Thomas Jefferson.
Since that time, it has happily naturalized in some of the most challenging areas throughout Canada and the US.
It is not uncommon to see sweet peas growing with wild abandon in open fields, railroad right of ways, abandoned lots, and along roadsides and fence rows.
When provided with the sun, rain, and minimum soil requirements, the perennial sweet pea does very well as a garden ground cover or as a privacy screen when given lattice or other structures to climb.
It’s an excellent climbing plant for covering embankments, slopes, or unattractive rocky areas.
Everlasting sweet pea flowers make a pretty and whimsical addition to cottage and border gardens and look lovely tumbling over a fence or wall.
Individual sweet pea plants also make excellent hanging basket candidates.
Surprisingly, even though this is a herbaceous vine, the cut flowers do quite well in arrangements.