Japanese pea-vine, beach pea

lathyrus japonicus

Also known as: ["seaside pea","sea pea"]

Family: Fabaceae Genus: Lathyrus Category: Flowers

Overview

A hardy, trailing or climbing legume native to coastal regions, known for its pinkish-purple flowers and ability to thrive in sandy soils.

Benefits & Perks

["drought tolerant","wildlife attractant (bees, butterflies, birds)","low maintenance"]

Botanical Classification

Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Fabales
Family: Fabaceae
Genus: Lathyrus
Botanical Name: Lathyrus japonicus

Plant Characteristics

Basic Information
  • Category: Flowers
  • Suitable Location: coastal areas, open meadows, or rock gardens
  • Suitable For:
    Outdoor Landscapers Wildlife Supporters Beginners
  • Is Weed: No
  • Allergenicity: low
Environmental Needs
  • Climate: {"temperatureRange":"5–30°C"}
  • Hardiness: {"zones":"3–8"}
  • Misting: rarely required, only if grown in very dry indoor conditions
  • Drainage: Fast-draining to prevent waterlogging.
  • Soil Type: Well-draining, loamy soil with added organic matter.
Maintenance Level
  • Maintenance Level: low
  • Toughness Level: high
  • Pruning Frequency: Light pruning as needed; major pruning in late winter or early spring before new growth.
  • Pruning Intensity: Moderate; remove up to one-third of old growth annually to rejuvenate.
Care Details

Ideal Sunlight Coverage:
Full sun (6–8 hours/day); tolerates partial shade but blooms best in direct light.

Sunlight Tolerance Tips:
Acclimate plants gradually to full sun if moved from shade; protect from intense midday sun in hot climates; ensure good air circulation to prevent mildew.

Warning Signs: Yellowing leaves (overwatering); stunted growth (poor soil fertility); root rot (poor drainage).

Care Requirements

Care Difficulty
easy

moderate

Sunlight

full sun to partial shade

Rotate plant for even light exposure; use shade cloth in extreme heat; avoid placing near reflective surfaces that intensify light.

Watering

every 7–10 days during active growth, less frequently in dormant periods

Water thoroughly but infrequently; ensure good drainage; avoid wetting foliage to prevent fungal issues.

Soil

well-draining, sandy loam with moderate organic content

pH: Slightly acidic to neutral (pH 6.0–7.0).

Use raised beds for better drainage; avoid heavy clay soils; amend with organic matter annually.

Temperature

Prefers cool to moderate temperatures (60–75°F/15–24°C); can tolerate cooler nights.

Avoid placing near drafty windows; use shade cloth in summer; protect from frost in winter.

Fertilizing

every 4–6 weeks during growing season with balanced liquid fertilizer

Apply fertilizer after watering to prevent root burn; stop fertilizing when plant is dormant; use organic options for gentle feeding.

Propagation

Methods

Seed or stem cuttings; seeds are more reliable for home growers.

Step-by-Step Propagation Guide
  1. Take cuttings with 2–3 nodes.
  2. Dip in hormone (optional).
  3. Plant in medium.
  4. Maintain humidity.
  5. Or sow seeds shallowly and keep moist.

Best Time: Spring or early summer for cuttings; autumn for seeds (stratification may be needed).

Environment

Warm (65–75°F/18–24°C), high humidity, and indirect light for cuttings; consistent moisture for seeds.

Medium

Well-draining mix like perlite and peat moss for cuttings; sterile seed starting mix for seeds.

Hormone

Rooting hormone can help with cuttings but is not strictly necessary.

Timeline

Cuttings root in 3–6 weeks; seeds germinate in 2–4 weeks with stratification.

Tools Needed

Pruners, rooting hormone, propagation tray, humidity dome, well-draining medium.

Quick Tips

Use sharp, sterile tools for cuttings; keep soil consistently moist but not waterlogged; provide bottom heat for faster rooting.

Pruning & Repotting

Pruning Guide
Method

Pinch back tips for bushier growth; cut back leggy stems to a healthy bud or node.

Pruning Plan

Prune to maintain shape, encourage bushiness, and remove dead or diseased growth.

Tools

Pruning shears, sharp scissors, gloves.

Checklist

Sterilize tools; prune dead/damaged growth; shape plant; avoid over-pruning.

Repotting Guide
Best Season

Early spring before active growth begins.

Pot Size

Increase pot size by 2–3 inches in diameter.

Method

Remove plant gently; trim roots if necessary; repot in fresh, well-draining soil with a slightly larger pot.

Suggestions

Repot every 2–3 years or when roots fill the pot; beneficial for container-grown plants.

Checklist

Choose new pot; prepare fresh soil; inspect roots; repot gently; water lightly after repotting.

Advanced Care Tips

Watering Mastery
Watering Checklist

Check soil moisture; water deeply; ensure drainage; avoid wetting leaves.

How to Apply Water Properly

Water at the base of the plant, ensuring moisture reaches the root zone; allow excess water to drain away; water in the morning to reduce evaporation and fungal risk.

Pro Tip: Use a watering can with a narrow spout to direct water precisely to the root zone.
Watering Schedule Tips

Water deeply once the top inch of soil is dry; reduce frequency in winter to prevent root rot.

Soil Improvement

Add perlite or coarse sand for drainage; incorporate compost for fertility; ensure good aeration.

Temperature Stress Management
Signs of Temperature Issues

Wilting, yellowing leaves, or stunted growth in extreme heat; leaf drop or browning in cold stress.

Cold Stress

Slows growth; may cause leaf discoloration or dieback in prolonged cold; vulnerable to frost damage.

Solution: Provide frost protection in cold climates; avoid sudden temperature drops; mulch to insulate roots.

Hot Stress

Leaves may wilt, scorch, or drop; flowering may be reduced in excessive heat.

Solution: Provide afternoon shade; increase humidity; water deeply to cool roots; use reflective mulch.

Fertilizing Guide
Fertilizing Checklist

Check fertilizer type; dilute correctly; apply during active growth; avoid winter feeding.

Fertilizing Method

Use balanced liquid fertilizer diluted to half strength every 4–6 weeks during growing season; avoid fertilizing in winter.

Common Problems & Solutions

Yellowing leaves in Lathyrus japonicus may indicate nutrient deficiencies, such as nitrogen or iron, or could be a sign of stress from environmental factors like overwatering or poor drainage.

Wilting in Lathyrus japonicus is often a response to water stress, either due to insufficient watering or root damage from pathogens, leading to reduced turgor pressure in plant tissues.

Leaf spots on Lathyrus japonicus may be caused by fungal or bacterial pathogens, leading to reduced photosynthetic efficiency and potential defoliation if the infection is severe.

Rotting, particularly root rot, can occur in Lathyrus japonicus when the soil is excessively moist, promoting fungal infections that degrade root tissues and impair water and nutrient uptake.

Toxicity Warning

Cats
Slightly Toxic

Cats are susceptible to neurolathyrism if they consume large quantities of the seeds or young pods of Lathyrus japonicus. The condition can lead to severe neurological damage.

⚠️ Symptoms:
weakness paralysis difficulty walking neurological signs
🌿 Toxic Parts:
seeds young pods
⚡ Toxic If:

if eaten

Prevent cats from accessing the seeds and young pods. Seek veterinary care immediately if ingestion is suspected.
Dogs
Slightly Toxic

The seeds and young pods of Lathyrus japonicus can cause neurolathyrism in dogs, leading to neurological symptoms. Prolonged or excessive consumption is necessary to induce toxicity.

⚠️ Symptoms:
weakness paralysis difficulty walking neurological signs
🌿 Toxic Parts:
seeds young pods
⚡ Toxic If:

if eaten

Keep dogs away from the seeds and young pods. Contact a veterinarian if ingestion is suspected.
Humans
Slightly Toxic

Lathyrus japonicus contains toxic amino acids that can cause neurolathyrism, a condition characterized by neurological damage, particularly when consumed in large quantities over a prolonged period. The young pods and seeds are the most toxic parts.

⚠️ Symptoms:
neurological damage weakness paralysis difficulty walking
🌿 Toxic Parts:
seeds young pods
⚡ Toxic If:

if eaten

Avoid consuming large quantities of seeds or young pods. Consult a healthcare professional if ingestion occurs.
Important: Keep this plant out of reach of children and pets. If ingestion occurs, contact poison control or veterinary services immediately.

Frequently Asked Questions

Q: Is Lathyrus japonicus toxic to pets?

A: It is mildly toxic to dogs and cats if ingested in large quantities.

Q: Does this plant require much care?

A: No, it is low maintenance and thrives in sandy, coastal conditions.

Q: Does it attract wildlife?

A: Yes, it attracts bees, butterflies, and birds due to its nectar-rich flowers.

Quick Reference
Family: Fabaceae
Care: easy
Light: full sun to partial shade
Water: every 7–10 days during activ
Suitable For: ["outdoor landscapers","wildlife supporters (attracts bees, butterflies, birds)","beginners"]
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