Source
r/askscience•
davidstuart

Ivy grows up trees in a left-handed spiral. Why, and does it change direction in the southern hemisphere?

Taking a late-winter hike in the forest today, I could see a lot more of the forest than usual due to the lack of leaves. I noticed many trees that had ivy growing up the trunk. Except for poision ivy (which grows straight up the trunk), all the other types of ivy plants spiral up the trunk in the same direction. From a birds-eye view, the ivy curved around the trunk in a clockwise fashion as it climbed. That was true without exception in more than 50 trees I saw with ivy. an example Why a left-handed spiral, and would it change in the southern hemisphere??

Posted Mar 2, 2012, 1:19 AM UTC

168
lurker2121•

Not all twining stems grow counter clockwise some grow clockwise. It is dependent on the species of plant.

5
davidstuartOPOrganic Chemistry | Polymer Chemistry | Coatings/Adhesives•

Do you have any references? I'd love to know which ivies go which way!

2
lurker2121•

I found this in a quick search. My original source was life. My parents were very big into gardening when I was a child. I don't have time right now. But, if you want some more information let me know and I'll see what I can find when I have time.

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davidstuartOPOrganic Chemistry | Polymer Chemistry | Coatings/Adhesives•

thanks, that is great!

1
Veonik•

Is it known what influences which direction a vine will grow? Do all plants of the same species grow in the same direction?

1
lurker2121•

See my reply to davidstuart above.

1
Strange_Party_Games•

I think this may be the result of the Coriolis effect. I know wind currents traveling from the Arctic due south veer to their right, which results in a clockwise motion if in the northern hemisphere. This is from the Earths rotation. In the southern hemisphere you find the opposite. Again, only an idea. I don't know how the effect would affect anything this close to the crust.

-11
oceanofsolaris•

Hmm, I don't really believe the Coriolis effect has any direct influence. While the Coriolis effect is strong enough to have an impact on very large scales, it is usually negligible on smaller scales. Furthermore the impact of the Coriolis effect depends on the speed of the object in question and plants are fairly static.

4