Twining Direction in Beans – are Scarlet Runner Beans Different?

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Robert Pavlis

I was working on my new book, Plant Science for Gardeners (to be released spring 2022), and came across a claim that most beans twine anti-clockwise, but that runner beans (Phaseolus coccineus) twine clockwise. This claim was on a government extension site, so it just might be true. It seemed really odd to me, but why would someone make this up? Surely this is something that is easy to check?

I have been growing runner beans for many years but I decided not to plant any this year so I couldn’t even check my garden.

There are also claims that plants, including beans, twine differently in the Southern and Northern Hemisphere. The idea that water drains in a different direction in the south is a myth, so what about twining vines?

Twining Direction in Beans - are Scarlet Runner Beans Different?
Twining Direction in Beans – are Scarlet Runner Beans Different?

Twining Direction in Plants

Some vines gain support by wrapping their stems around things and this is called twining. Such vines are called twiners. About 90% of twining vines turn counterclockwise as you look down at the vine from above. Some, like the cucumber, curl either way.

Plant Science for Gardeners by Robert Pavlis
right-handedness in vines
right handedness in vines

Some people like to use the terms clockwise and counterclockwise (or anticlockwise). These terms are confusing if you don’t know that you need to look at the vines from above.

Others prefer the terms right handed and left handed. Hold you right fist with the thumb pointing up (it’s the trellis). Your index finger is the growing vine and it is growing from left to right as you look at your own fist. That is a right handed twine.

Anticlockwise = right handedness.

Twining in Beans

The majority of beans twine counterclockwise. So what about runner beans?

I checked several pictures of runner beans online and they all twined counterclockwise. I asked members in my master gardener group to check their plants and everyone who responded confirmed they twined counterclockwise. Our Facebook Group also checked – same answer.

No one had beans of any type twine clockwise!

The picture below was taken from one blog claiming runner beans twine clockwise, but if you look at the picture it clearly shows them twining anticlockwise! Why bother looking at your own picture when you can perpetuate a myth?

I don’t have any scientific proof – but I have quite a few gardeners confirming their runner beans twine counterclockwise.

runner beans twining counterclockwise
Runner beans twining counterclockwise

Do All Beans Twine the Same Way?

I looked at a number of pictures online and found no beans that twined clockwise. One person in our Facebook Group checked a dozen different beans – all twined counterclockwise.

Building Natural Ponds book, by Robert Pavlis

I’ll assume they all twine the same way, until someone sends me some proof that some species twine differently.

YouTube video

Difference Between Green Beans, String Beans and Runner Beans?

Are confused about different kinds of beans. Learn the differences between them here, Difference Between Green Beans, String Beans and Runner Beans?

Twining Beans and the Coriolis Effect

You may have heard that water drains in one direction in the northern hemisphere and a different direction in the southern hemisphere; the Coriolis effect. Some people claim that this also happens with beans, but I have found no evidence of this. I am fairly sure all beans twine the same way all over the globe. Twining is controlled by genetics and not location.

By the way – the Coriolis effect for draining water in sinks and flushing toilets is also a myth.

The Coriolis effect is real and it does affect to the movement of large air masses over the earths surface and it is responsible for the direction in which hurricanes/cyclones spin. But the force is too small to affect the water going down a drain.

Why Does the Twining Direction Matter?

You might think that this whole topic is a bit silly, but it can be quite useful to gardeners. Vines need help clinging to their support, especially as small seedlings and we routinely give them a help by wrapping vines around a support.

Next time you are in the garden and wondering which way to wrap them, just make a fist with your right hand and wrap them in the direction of your fingers. You will be right with 90% of the plants.

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

13 thoughts on “Twining Direction in Beans – are Scarlet Runner Beans Different?”

  1. A subject that has long interested me, but I have to take issue with you on the question of direction. If we are asking in which direction the bean climbs, then we have to look at it from the bean’s point of view – which is from below. The bean is climbing upwards and therefore clockwise. Thanks for your post.

    Reply
  2. This is not, in my opinion a silly matter. Ever since I learned the interesting fact that plants face the sun to get the most benefit from photosynthesis because a growth factor in the stem is damaged by uv light leaving the opposite side of the stem to grow more, all of these aspects of plant growth are interesting.
    However, as a twining plant would presumably reap equal uv benefit no matter which direction it wraps, WHY do they mostly all go in one direction?
    Thanks as always for interesting issues.i

    Reply
  3. The picture you include says he is checking the twine direction from below. All your information checks the direction from above. This makes the picture correct about the direction of the pictured bean, but wrong about all other plants.

    Reply
  4. You should clarify that the Coriolis effect is real. It applies to the movement of large air masses over the earths surface, and how the motion is affected by the rotation of the earth. It is responsible for the direction in which hurricanes/cyclones spin. The mass of water flowing down a drain is simply too small to be affected.

    Reply
    • It’s not that the mass of water is too small to be affected, rather the force applied is too small & the water travelling over too short a distance to have a measurable effect.
      Coriolis effect moves a bullet weighing less than 5grammes far enough for us long distance shooters to find it helpful to calculate it.

      Reply
  5. In the sixth paragraph ( Others prefer the term… ) you say to hold your right fist with some up and the index finger shows the direction of growth. You say it is left to right. But I think you meant right to left. Right to left would be anti-clockwise. You stated it correctly later on. This is not meant to be critical. It is meant to make sure the text is correct. You do great work. Keep it up!

    Reply
      • OK, I was looking DOWN on my fist. My brain got stuck on looking down on the vine, so I looked down at my thumb. Ha! But now I see what you were saying by keeping fist closed and looking its side, not from the top. OK… NEVER MIND. 🙂

        Reply

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