I grow mine on a 4 foot high fence of 8 foot sections of treated lattice, with 2x4's at top and bottom edge, with 4 x 4 posts, every 8 feet. So I cannot imagine the vines would ever get too heavy for your old ladder. Consider if any commonly occurring high winds would blow it over, when it is fully covered with vines. Post a photo, if you can, when you have planted it.

As bogturtle suggests wind will be more of an issue than weight! make sure you secure it to the ground!! It will never get heavy enough to damage the ladder unless the ladder was in super rotted condition! I wouldn't prune the bean vine though, just keep directing the shoots back to the ladder, you'll lose a lot of flowers by pruning!

Great I'm glad to hear the ladder will do fine. I will be anchoring the ladder into the ground with fence poles to keep it from getting blown over. I appreciate the info on not pruning it, I want lots of flowers so I won't prune, I'll just keep wrapping it around the ladder instead. Thanks so much!!

I do love this vine it is so pretty will plant it again.Mine did stay kinda woody but it was in a pot .I still loved the flowers will plant it in full sun this year.

Orcascove,
You may also want to start the seed indoors a bit before your last freeze date. They won't sprout in cool soil if you plant them out, mine wait until early july when the soil warms to sprout if I plant them directly. I usually pot a few up in early April for Memorial day planting, even those tend to stall until the ground warms, expect flowers very late August through first frost unless you start them indoors.

I started mine 8 weeks before frost last year. That was my first time growing them. At first they had a few flowers and I thought they were Ok. But they kept getting bigger and more and more flowers, then purple beans. They are great! The hummers love em and they make great cut flowers. I grew about eight. Filix.