There has been much confusion in the naming of this plant, with the closely related Lathyrus magellanicus being seen by many authorities as no more than a synonyn of this species[
]. However, according to a number of reports, Lathyrus magellanicus is a distinct species with minor botanical differences and is somewhat hardier than Lathyrus nervosus[
]. The two species are therefore being treated as distinct here[
Lathyrus americanus (Mill.) Kupicha
Lathyrus armitageanus Loudon
Lathyrus nervosus Boiss.
Lathyrus trigonus Vogel
Common Name: Lord Anson's Pea
Lathyrus nervosus is a vigorous herbaceous perennial, climbing plant with stems that scramble over the ground and climb into the surrounding vegetation, attaching themselves by means of tendrils; it can grow up to 60cm tall.
The plant is harvested from the wild for local use as a food. It is sometimes grown as an ornamental in gardens.
Although no specific records of toxicity have been found for this species, the seed and other parts of many Lathyrus species contain a toxic amino acid. It is produced in the plant at about the same time that the seed starts to develop. In small quantities the amino acid is innocuous, and the seeds of several Lathyrus species are eaten as a nutritious part of the diet. However, in larger quantities (the seed should form less than 30% of a balanced diet), it can cause a very serious disease of the nervous system known as 'lathyrism'. Symptoms appear as a paralysis of the muscles below the knees, pains in the back, followed by weakness and stiffness of the legs and progressive locomotive incoordination[
S. America - Chile, Argentina, Uruguay, southern Brazil.
Coastal sands, gravel and open grassland[
Lathyrus nervosus is not a very cold-hardy plant, it dislikes prolonged frost but can tolerate occasional short-lived falls in temperature to about -10Â°c[
]. It grows best in areas with cool, moist summers[
An easily grown plant, succeeding in any moderately good garden soil but preferring a position in full sun[
]. Prefers a rich soil in a cool position in sun or semi-shade with plenty of moisture in the growing season[
]. Grows well on a hot, sunny bank[
A very ornamental plant[
] it is a short-lived perennial[
This species is not really a climber, it grows best when allowed to sprawl downwards. Plants scramble through other plants, supporting themselves by means of tendrils[
Young plants are extremely attractive to rabbits[
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[
Seed - cooked[
]. Some caution is advised, see the notes above on toxicity.
Pre-soak the seed for 24 hours in warm water and then sow in early spring in a cold frame[
]. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer.
If you have sufficient seed, then it can also be sown in situ in mid spring[