Why Are Sweet Pea Peas Toxic?
Sweet pea plants (Lathyrus odoratus) are distinct from edible garden peas (Pisum sativum) and contain toxic compounds. The seeds, in particular, hold a dangerous chemical known as beta-aminopropionitrile (BAPN), which is responsible for the poisoning syndrome known as lathyrism. When ingested, especially in significant quantities over an extended period, this neurotoxin can have severe effects on the nervous and musculoskeletal systems.
The Health Risks of Lathyrism
Lathyrism, the condition caused by consuming sweet pea seeds, can manifest in two forms, affecting both the nervous system and the skeletal structure.
- Neurolathyrism: This neurodegenerative disease causes motor neuron damage that leads to muscle weakness, paralysis of the lower limbs, and spastic gait. In severe cases, it can be permanent and debilitating. Symptoms may include tremors, weakness, and a shuffling walk.
- Osteolathyrism: This form impacts connective tissues, leading to bone deformities and skeletal pain. It primarily affects bone structure and the mesenchymal connective tissues.
It is crucial to understand that these conditions can develop with repeated consumption and should not be taken lightly. Symptoms can often be delayed, making it difficult to immediately link the illness to the plant's consumption.
Can you eat other parts of the plant?
While the seeds and pods are the most toxic, the entire plant should be considered unsafe for consumption. The flowers are sometimes used as a garnish in small quantities, but due to the significant risk of confusion and toxicity, it is best to avoid consuming any part of the ornamental sweet pea plant. In contrast, young shoots and leaves of the edible garden pea are perfectly safe to eat.
Sweet Pea vs. Edible Pea: A Comparison Table
To ensure safety in your garden, it's essential to know the key differences between the toxic sweet pea and its delicious, edible relative. The table below highlights the distinguishing features.
| Feature | Sweet Pea (Lathyrus odoratus) | Edible Garden Pea (Pisum sativum) |
|---|---|---|
| Appearance | Showy, frilly flowers in various colors (pink, purple, white); winged, rough stems; typically smaller leaves. | Less showy, often white or pale flowers; round, succulent stems; larger leaves. |
| Pods | Hairy, brown pods that contain toxic seeds. Pods dry out and split open when mature. | Smooth, green pods that are edible (like snow peas and snap peas) or contain edible green peas (shelling peas). |
| Scent | Distinctly sweet and fragrant flowers. | Typically little to no floral fragrance. |
| Toxicity | All parts, especially the seeds, are toxic. Contains neurotoxins like BAPN. | All parts are edible and non-toxic. |
| Purpose | Primarily grown as an ornamental flowering plant for gardens and cut flowers. | Grown as a vegetable for culinary use. |
How to Safely Identify and Handle Sweet Peas
Proper Identification
- Look at the flowers: Ornamental sweet peas are known for their vibrant, often frilly flowers in shades of purple, pink, red, and white. If you have a plant with these highly fragrant flowers, it is almost certainly the toxic kind.
- Examine the pods: Sweet pea pods, which appear after the flower fades, are often hairy and turn brown as they mature. Edible pea pods are smooth and vibrant green. If you are unsure, do not taste it.
- Check the stems: Edible pea plants have smooth, rounded stems, whereas ornamental sweet peas have flattened, winged, and somewhat rough stems.
Safe Handling in the Garden
- Harvesting seeds: When harvesting seeds from ornamental sweet peas for future planting, wear gloves to prevent potential skin irritation and store the seeds in a clearly labeled, sealed container, away from children and pets.
- Educate others: If you have ornamental sweet peas in your garden, make sure that children, house guests, and other gardeners know they are not edible. The name can be misleading and lead to accidental consumption.
- Keep pets safe: Pets can also be susceptible to sweet pea poisoning. Keep them away from sweet pea plants to prevent them from ingesting seeds or other parts of the plant.
What to Do in Case of Accidental Ingestion
If you suspect that someone, especially a child or a pet, has ingested sweet pea seeds or pods, take immediate action. While symptoms from small, accidental consumption may not appear immediately, it is crucial to seek professional medical or veterinary advice. Have the name of the plant (Lathyrus odoratus) ready when you contact poison control or a medical professional. This is particularly important for pets, as some studies have shown the potential for severe symptoms even in small doses.
Conclusion
While the sight and fragrance of sweet pea flowers are a delight to the senses, the peas and pods they produce are a danger, not a treat. The ornamental sweet pea (Lathyrus odoratus) is not the same plant as the edible garden pea (Pisum sativum). Consuming the seeds of a sweet pea plant can lead to lathyrism, a serious and potentially permanent health condition affecting the nervous and skeletal systems. By understanding the key differences in appearance, handling the plants with care, and educating others, you can safely enjoy the beauty of sweet pea flowers without risking accidental poisoning. When in doubt about a garden plant's edibility, always err on the side of caution and do not consume it.
For more information on toxic plants, you can visit a reliable resource like the Cornell University Poisonous Plants Informational Database.
