Plenty of foliage, two feet or so high foliage, tendrils climbing to top of six foot wigwam, when will they flower, in large container
When you fertilize, use a low nitrogen fertilizer so you don't get leaves instead of flowers. Also, make sure they are getting plenty of water. Here is more on their care:
https://www.gardeningknowhow.com/edible/vegetables/beans/half-runner-beans.htm
https://www.rhs.org.uk/vegetables/runner-beans/grow-your-own
I used to have fantastic runner beans but about 4 years ago the flowers started dropping off sure it’s not birds or insects. Any ideas and suggestions to stop it.
Beans, naturally, increase nitrogen in the soil. If crops are not rotated, then it may be necessary to provide some phosphorus and potassium. This can offset the nitrogen, and raise the pH a little making nitrogen less available to the plant.
Here is more information on the bean: