DISCLAIMER: Do not eat or otherwise use any plants without doing your own research. I will not be liable if you misidentify a plant or follow misinformation I give (although if I give misinformation, please let me know!).
Sweet pea is often grown as an ornamental, or simply grows wild as a weed in lawns.
Commonly found in horticultural gardens everywhere, it’s no wonder many people have asked whether sweet peas are considered edible. Unfortunately, the answer most commonly given is: “No, it’s deadly poisonous.” While it’s always good to take multiple trusted sources as likely true, the problem is that people dig no deeper. Does the sweet pea have poisonous qualities? Yes, but the plants that don’t have poisonous qualities whatsoever are few and far between.
Sweet pea pods can be shaped like bean pods or pea pods, or entirely different. (Image used under creative commons license)
Why is there so much confusion, with some people claiming it to be edible and others to claim it will take your life? There is an amino acid within the plant that, when the plant is consumed in excess quantities over a long period of time (a study found that it takes approximately 30% of your diet comprised of sweet peas over 3 months or more to cause damage), it can cause a neurodegenerative and muscular wasting disease known as lathyrism. However, no fatalities have been directly attributed to sweet peas, and most people are unlikely to subsist solely off of them when there are many other sources of food around.
Note how the stems have winged edges. In cross section, the stem will have a shape similar to that of a squinted eye. (Image used under creative commons license)
The winged stems are host to both leaves and tendrils. The leaves can grow in an alternate or opposite pattern and are occasionally succulent. The plants can be hairy or smooth, as can the pea pods, which grow in a variety of shapes. The flowers are like all other plants in the pea or bean family, and can be many colors, ranging from blue to pink to purple. The key feature to ensure you have the right plant is to look for winged stems. While there are a few members of the Lathyrus genus which have round stems, they are few and far between and best avoided to ensure you don’t consume a toxic lookalike.
Sweet peas have the distinctive bisymmetric flower common for plants in the Fabaceae (pea and bean) family.
The flowers can be eaten raw or cooked, and add a colorful garnish to salads and other foods. The tips of the vines and the young shoots, leaves, and tendrils can be eaten cooked. The most nutritious part of the plant, the pods and their seeds, can technically be eaten raw (though they’re usually tough) and are best cooked. Fried in butter with a splash of vinegar and lemon juice and topped with parmesan is the best way to go, but in case you’re in a survival situation they’re still quite tasty plain. The roots of one species, Lathyrus tuberosus, grow tubers which can be eaten cooked.
And, as usual, make sure not to subsist entirely off of these just to be safe. Happy foraging!