About a month ago I got the idea to try growing pole beans (Kentucky Wonder) and using my sunflowers as support instead of bothering to put up a trellis. Of course it wasn't until after I bought the seeds that I paused to wonder if the sunflowers would be able to keep ahead of the beans. I have no experience with growing pole beans.
The Sunflowers: One portion of the sunflowers are a variety I grew last year. It's a branching variety, the seed pack claimed they would grow to 6 or 7 feet. In my garden they reached 8 feet easily. A second is a mixed pack with at least 3 varieties in it, I think they are branching varieties and they also claim a final height of 6 or 7 feet. A third set is actually a descendant of the first variety (apparently I missed one head when I was clearing up stalks from last years flowers).
I'm fairly sure the sunflowers can handle the weight as I needed a hatchet to cut down the stalks this spring. I'm not too concerned about the beans wanting to get any taller than the sunflowers as I can't harvest any higher than I expect the sunflowers to grow anyway.
The real question is will the sunflowers be able to stay keep ahead of the beans? At the moment the sunflowers have about a 3 week head start (they're 6 inches tall, and likely to grow quick with the 70-80 degree days forecast for most of the week. Should I give them a little more time to put on size before I complicate things?