I realise I've put runner beans close to an overhanging damson tree.

The beans closest to the damson have scaled my supports and have bridged the gap between support and tree and started to climb on into the branches of the damson.

Leaving aside unsuitability of growing vegetables close to trees (loss of light and nutrients), is there a problem with the beans climbing on and on into the tree? (apart from the obvious one of it being hard to harvest the crop of course).

What I mean is, will the plants put excessive effort into climbing and set fewer flowers/beans?

If so, should I just pinch out the tops?


My opinion* is you should grow as high as you can reach without the runners affecting other plants. If they want grow higher, trim them. Above all, don't do anything that would cause you to miss picking ripe pods!

The point of growing beans is to harvest as many pods as possible, with the possible secondary purpose of putting nitrogen back into the soil as part of a rotation (but that's not relevant to plant height). Thus the principal downsides to allowing the beans to grow too high are:

  1. You can’t reach the beans (especially if you're petite) and so you don't pick them promptly causing the plant to decide it's fulfilled its biological purpose and shutdown.
  2. Energy is unnecessarily expended in growing more infrastructure (runners) rather than flowers that would become beans. < EDIT: This is wrong. See comment.
  3. If you did, instead, trim the plant at the top, it would make more lateral branches and so fill in usable space at the top of the trellis where reachable beans would grow.

The downsides to allowing your beans to grow on to another plant when you already have separate trellising:

  1. The beans are more difficult to pick, increasing the risk of missing a ripe pod, causing the same problem of the plant deciding to shut down.
  2. The runners could damage the other plant when they entwine around it.
  3. Transfer of plant diseases could occur.
  4. The finished beans are harder to clean up at the end of the season when tangled into something that's still productive.

[*] Posting on behalf of a friend, Francoise, to whom I posed this question (and who's not ready to join G&L stack exchange)

  • I have checked with others about the idea that "Energy is unnecessarily expended in growing more infrastructure (runners) rather than flowers that would become beans" per #2 and that is wrong. Beans are apparently not like strawberries in that way, so that is not a reason to chop off the tops. More infrastructure is fine because it will keep producing more beans in these places. The other 2 practical reasons are the only ones to pay heed to, so it's a much of a muchness.
    – Lisa
    Dec 11 '11 at 7:08

Every time my runner beans grow beyond or above where I want them to I pinch them off and they seem to cope just fine, they don't seem to suffer any adverse effects and flower as you would expect.

Admittedly, I restrict their height on purely cosmetic grounds, so I haven't seen how they perform if left to overgrow branches above them.


In my experience its best to just let the bean climb. As far as I know, the larger the plant gets, the more beans you'll get, since the plant has a bigger platform and more nodes to produce bean pods. Might be a different story depending on the variety of bean though.


There may be two questions here - or at least, I  have a slightly different question. We use 6-foot-high trellis, and this year we had record yield, with the beans growing all over themselves into huge "ropes" at the top of the trellis. So my question is about what to do when there's nothing for the beans to climb up farther on.

Without some solid advice to the contrary, if we get another crop like that I'm going to prune. I think the plants put a lot of effort into making runners that did them no good.

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