Thursday, October 29, 2015
Sword bean (Canavalia gladiata)
Everything about the sword bean (Canavalia gladiata) is impressive. From the time the first true leaves emerge from the seed, until the pods split open to reveal their giant pink seeds, there's something awe-inspiring about this plant.
The pink seeds are about the size of a quarter, and get even larger if soaked before planting.
The cotyledons are pulled up out of the ground as the roots head downward, and when the first true leaves emerge, they can be 6-8 inches in diameter. Here's a seedling next to a 4-inch pot for scale:
From there, they quickly shoot up and start twining around, looking for something to climb on. Yes, this bean is a climber, so give it a sturdy support that will endure throughout the growing season. I like to grow them on dead trees, since many types of garden supports will collapse under the weight of the vines.
By mid-summer, the lavender-pink flowers appear in clusters all up and down the vine.
If pollination is successful, the bean pods start to develop, and eventually reach over a foot in length. It takes about 90 days from planting for the beans to reach a maturity at which they can be picked and eaten.
For fresh eating, the pods should be picked while they're still tender, and before the beans start to swell up too much inside. At that stage, the pods can be sliced cross-wise and boiled until tender. Discard the cooking water.
If you wait too long to eat them fresh, just let them finish maturing until the pods are dry. It will take an additional 2-3 months of growing to get to this stage.
Then the beans can be shelled out and cooked, but require soaking overnight and thorough cooking in 2-3 changes of water to rid the beans of potential toxins. For this reason, they are usually picked and eaten when the pods are still tender.