Los Angeles Herald, February 24, 1907.
The Journey Of A Root
From Santa Barbara, California, there comes a story of a most interesting freak of vegetable life, which is strictly vouched for.
Through a certain garden ran, some years ago, a sewer made of redwood timber. This sewer was again cased by an outside sewer.
Across the sewer there was built a brick wall many feet high, and in such a way that is was pierced by the inner sewer, which it enclosed tightly, while the outer sewer ended abruptly against the wall.
The outside sewer casing had in course of time decayed, and a eucalyptus tree, standing some sixty feet away, had taken advantage of this and sent one of its roots to the coveted spot in a direct a line as possible.
Here the root entered the outside sewer and followed its course as far as it could. At last it came to the wall which shut off its course, and it could go no further, the inside sewer being perfectly tight.
But on the other side of the wall the sewer and its casing continued, and this eucalyptus tree evidently knew how t0 get there.
Some three feet high in the brick wall there was a little hole an inch or two in diameter, and this the eucalyptus tree was aware of, as its big root began to climb the dry wall and face the sun and wind until it found the hole, through which it descended on the other side and entered the sewer again and followed it along as formerly.
How did the tree know of the hole in the wall?
How did it know that the sewer was on the other side?
How could it direct the root to go and find the place with such precision?
The roots of any plant grow always and unerringly in the direction of its food, just as the eucalyptus tree did.
Thirteen years ago I came across this historic newspaper piece in the archives and filed a copy here on this weblog as an unpublished draft.
Yesterday I was in the book nook at Santa Barbara Botanic Garden, browsing through volumes of interest, when I happened across a single sentence that struck with force, triggered memory recall, and as Will Hunting said, blew may hair back. (Movie clip: Good Will Hunting 1997)
This old newspaper article relates what was at the time an inexplicable feat of plant sentience.
How? How? How? They asked.
Some one hundred years later, we the humans are finally beginning to develop our understanding of plant intelligence, and we have something of an answer to those questions.
The aforementioned sentence of interest:
“Pea shoot roots appeared to be able to hear water flowing through sealed pipes and grow toward them,. . .”
—Zoë Schlanger,
The description related in the newspaper article is a remarkable, anecdotal case in point example of what scientists today have discovered.
Pea plants have demonstrated an ability to sense, not only differing amounts of soil moisture, and to use this information to direct their root growth toward primary sources and the wettest places. Which is probably obvious, that roots grow toward water.
But what is not so obvious; plants have also demonstrated an uncanny ability to sense acoustic vibrations in the soundscape made by the force of running water and to act accordingly.
Tree root growing down into the circular tree mold formed when a lava flow covered the forest in Volcanoes National Park and surrounded the trees. The moisture in the tree kept the trunk from burning just long enough for the lava to cool and form the cast. (March 2025)
“Because water is essential to life, organisms have evolved a wide range of strategies to cope with water limitations, including actively searching for their preferred moisture levels to avoid dehydration.
Plants use moisture gradients to direct their roots through the soil once a water source is detected, but how they first detect the source is unknown.
We used the model plant Pisum sativum [pea] to investigate the mechanism by which roots sense and locate water.
We found that roots were able to locate a water source by sensing the vibrations generated by water moving inside pipes, even in the absence of substrate moisture.
When both moisture and acoustic cues were available, roots preferentially used moisture in the soil over acoustic vibrations, suggesting that acoustic gradients enable roots to broadly detect a water source at a distance, while moisture gradients help them to reach their target more accurately.”
—Gagliano, M., Grimonprez, M., Depczynski, M. et al. Tuned in: plant roots use sound to locate water. Oecologia (2017)
“Acoustic gradients enable roots to broadly detect a water source at a distance,” say, for example, sixty feet away, through open air and dry surfaces.
Wild man, wild.
Jack Elliott's Santa Barbara Adventure 