Sword Beans - trying them as an annual

I'm in zone 6, and sword beans (Canavalia ensiformis or jack bean) and (Canavalia gladiata or sword bean) are tropical perennials, I'm going to try growing them both here. Has anyone done so?  Will they produce fruit in their first year?  Any chance heavy mulch would help them winter over? Any advice? Definitely putting them on an arbor.

I'm very curious to try them, I saw one and they fascinated me. And me being me, I ordered seeds!



I had to resize that image, credit to and link to the original https://minnetonkaorchards.com/wp-content/uploads/2022/09/Sword-Bean-Pod-SS-1559543753-1024x1536.jpg

Oh my! That's a giant bean pod!
I'd never heard of these.
Canavalia ensiformis:
Ken fern says "It grows best in areas where annual daytime temperatures are within the range 20 - 28°c, but can tolerate 14 - 36°c[418]. The foliage is intolerant of frost, but mature beans are unaffected[418]. It prefers a mean annual rainfall in the range 800 - 2,000mm, but tolerates 600 - 4,300mm[418]."
Grown as an annual in Japan and in Mexico....It sounds like the beans are used like runner beans (phaseolus) but need to be cooked well, as like many beans, they contain toxic alkoloids." Young pods can be harvested about 4 months after sowing[300]. Green pods can be harvested after 80 - 120 days, and mature seed after 180 - 300 days[418]."
Canavalia gladiata
Basically similar, differing in the following:
"The seeds of this species are red, with a hilum that extends nearly the whole length of the seed (white in Canavalia ensiformis, with a hilum that extends to less than half the length of the seed); the pod shape is more curved in this species; flower size and colour differ - pink or white in this species, purple in Canavalia ensiformis."

They are both used as green manures and have some medicinal uses too - they sound fascinating! Please do let us know how you get on. I suspect if you can grow runner beans you could grow these.

I do grow runner beans.
Thank you for the write ups. :D
Doesn't look like I'll get mature seed, but probably good pod crops.

I'm fascinated...

I was asked how big the seeds are... The red ones are the Canavalia gladiata

Canavalia gladiata - Sword Bean

The white ones are the Canavalia ensiformis

Canavalia ensiformis - Jack bean

For size comparison, these are some of the scarlet runner beans I  am currently harvesting

Phaseolus coccineus - Scarlet runner beans

Apologias for messy pictures, hard to take a picture of your own hand with your phone.  :D

So we think these might grow in the English Midlands, and be like giant runner beans to cook when young?!

I think so Ac - You'd need 4 months of warm weather though, might want to start them off under cover to get a longer season. I think you'd be unlikely to be able to save seed from them though to regrow, that would take 9 or 10 months warm according to theferns.info

Getting the seed could be a problem in the UK. I did find them on Amazon here if you fancy the risk, rarepalm seeds in Gedrmany list them or a DuckDuck search also pulls up the herbary who don't have their seed list available as yet, but might be worth checking later in the year (they look as if they do interesting bean seeds anyway :) )
this 'blog has some more detailed growing information which looks quite useful.

Has anyone grown these before? I'm trying to decide when to start them in the house, looking at when I trust the last freeze to be past, vs how big of a pot I want to deal with. I'd love to learn something along the lines of  "In one month they'll grow 12 inches high with a 9 inch root" etc....  


And rereading this thread, What I have seen is that the pods and immature beans are not toxic, only the mature ones. And that the common way to use the pods is diagonal slices and use like a green bean. I have seen lots of stir fry type pics of them.

I'm excited!  Just trying to figure out my pacing on starting them. Figured I'd ask here before I start running the net for info.

So, since I failed to even look for data on the net, I started them when I had time.
04-16-2025:   8 pots started, 4 of red beans, 4 of white, one bean seed per 6 inch pot.
04-24-2025: The first one is up! White bean. And it's HUGE! Biggest bean sprout I have ever seen.


04-27-25: That first one is only 3 days old, and it's already 6 inches high or so.


05-01-25: One week old, 14 inches high, clothespin for scale.


These are going to be amok!!!
In preparation for this post I dug down in a pot that has a red bean, it's about to come up.
We are getting chilly nights this week, I expect 41 or so  as the low in this microclimate (with north wind right on the place I plan to plant them), too chilly for baby tropicals to go outside yet. Hoping I don't have to give them support stakes before they even get outside :D  

Pearl Sutton wrote: Hoping I don't have to give them support stakes before they even get outside :D  

I keep a stash of used disposable chopsticks for just those situations! Slightly pointy on one end, light weight, and easy to get!