What Makes Ornamental Sweet Peas Dangerous?
Unlike their edible garden counterparts, ornamental sweet peas (Lathyrus odoratus) contain toxic compounds that are harmful to humans and pets. The primary concern lies in the seeds, which are particularly concentrated with these harmful substances, though all parts of the plant are considered toxic. The confusion often arises because both plants are part of the same legume family (Fabaceae), but they belong to different genuses: Lathyrus for the toxic variety and Pisum for the edible one.
The Toxin and Its Effects
The toxic properties of ornamental sweet peas are due to the presence of amino acids and aminonitriles. A key toxin is beta-aminopropionitrile (BAPN), which interferes with the cross-linking of collagen, the protein that provides structure to bones and blood vessels. This can lead to skeletal abnormalities and weakened blood vessels, a condition known as osteolathyrism and angiolathyrism. For other Lathyrus species, the toxin beta-N-oxalyl-amino-L-alanine (beta-ODAP) can cause neurolathyrism, a neurological condition resulting in paralysis and muscle atrophy. While Lathyrus odoratus primarily causes the former, the risk of neurological damage is why all ornamental sweet peas should be treated with caution.
Accidental vs. Chronic Ingestion
Accidentally eating a small amount of an ornamental sweet pea seed is unlikely to cause serious poisoning in humans. However, symptoms such as an upset stomach are possible. The real danger lies in chronic ingestion—eating large quantities over weeks or months, which is common in famine situations where people might resort to eating these hardy plants. This can lead to the severe and sometimes permanent symptoms of lathyrism. This risk highlights the importance of keeping these plants away from unsupervised children and curious pets.
A Crucial Comparison: Ornamental vs. Edible Peas
Distinguishing between the toxic ornamental sweet pea and the delicious, edible garden pea is vital for safety. They differ in appearance, fragrance, and structure. The following table provides a clear comparison to help you identify which is which.
| Feature | Ornamental Sweet Pea (Lathyrus odoratus) | Edible Garden Pea (Pisum sativum), e.g., Snap or English Pea |
|---|---|---|
| Stems | Slightly flattened, winged, and rough texture | Round and succulent texture |
| Flowers | Highly fragrant, vibrant colors (pink, purple, red, etc.) | Less fragrant, typically white or bi-colored |
| Pods | Shorter, skinnier, often hairy, and dull green | Longer, plumper, shiny, and bright green |
| Seeds | Poisonous | Safe and delicious to eat |
| Overall Use | Grown purely for ornamental purposes due to fragrance and color | Grown for consumption, rich in flavor and nutrients |
Identifying Your Peas Correctly
When identifying plants in your garden, pay attention to the stem and pod characteristics. If a pea-like plant has fragrant, brightly colored flowers and stems that are rough and winged, it is most likely a toxic sweet pea. In contrast, edible peas have a more tender, rounder stem and typically produce less showy flowers. Remember that some people may informally call edible sugar snap peas 'sweet peas,' which can cause confusion. Always use the scientific name or specific cultivar to be certain.
What to Do If You or a Pet Have Eaten Sweet Peas
If you have any suspicion that a child or pet has ingested the seeds or other parts of an ornamental sweet pea plant, it is crucial to act swiftly. For humans, contact a poison control center immediately for guidance. For pets, contact your veterinarian or the Pet Poison Helpline. While accidental ingestion of small amounts may not cause severe harm, it is best to seek professional advice to ensure proper management and to monitor for any adverse reactions. Do not attempt to induce vomiting unless instructed to do so by a medical professional. Early intervention is key to preventing serious health complications associated with lathyrism.
Conclusion
The question "Can humans have sweet peas?" is a critical one for gardeners and families. The clear and simple answer is no, if referring to the common ornamental variety, Lathyrus odoratus. The presence of toxic amino acids, particularly in the seeds, poses a serious health risk, with chronic ingestion potentially leading to the neurological disorder lathyrism. Knowing the distinct differences between these decorative flowers and edible garden peas is the best way to ensure safety. Always check the botanical name and visual characteristics to prevent a dangerous mix-up in your garden or on your plate. If unsure, assume the plant is toxic and avoid consumption. Remember, edible peas are part of the Pisum genus, while poisonous sweet peas belong to the Lathyrus genus.
For more information on poisonous plants, you can visit a reliable resource like Queensland Health's Poisons Information.
