Leaves Turned White

Wingstem leaves turning white. Why? (photo by Kate St. John)
Wingstem leaves turning white. Why? (photo by Kate St. John)

In July and August I noticed something I’d never seen before along the trails of western Pennsylvania — scattered instances of leaves turning white.

The leaves had been green but now their tips or even whole branches were white. The plant below had advanced to the stage where some of the stems were completely white.

Leaves in distress: top is white, 31 July 2017 (photo by Kate St. John)
Leaves in distress: top is white, 31 July 2017 (photo by Kate St. John)

The condition is called chlorosis and it means the plant is not producing enough chlorophyll to look green.  Since chlorophyll uses sunlight to make food for the plant, it’s a sign the plant is in distress.  But why?

Causes of chlorosis are wide-ranging.  Here’s the list from Wikipedia, with my [notes] added:

  • a specific mineral deficiency in the soil, such as iron, magnesium or zinc
  • deficient nitrogen and/or proteins
  • a soil pH at which minerals become unavailable for absorption by the roots
  • poor drainage (waterlogged roots)  [Not likely in this case.]
  • damaged and/or compacted roots  [Not likely in this case.]
  • pesticides and particularly herbicides may cause chlorosis, both to target weeds and occasionally to the crop being treated.  [Not likely in this case due to location.]
  • exposure to sulphur dioxide [Possible in Pittsburgh but not likely in this case.]
  • ozone injury to sensitive plants [Not likely in this case.]
  • presence of any number of bacterial pathogens, for instance Pseudomonas syringae pv. tagetis that causes complete chlorosis on Asteraceae.

Interestingly, the plants I photographed are in the Aster Family (Asteraceae) and one of them has complete chlorosis.

Was the 2017 growing season especially bad for the bacteria mentioned above?  Or does chlorosis happen every year and I’ve just not noticed?

If you know more about this condition in the wild, please leave a comment.  I’m really curious!

 

(photos by Kate St. John)

 

14 thoughts on “Leaves Turned White

  1. I have never seen or heard of this. I will be very interested to see what others have to say about this condition.

    1. Find an arborist to diagnose the problem. (In Pittsburgh, I call Bartlett Tree Experts for my own trees)

  2. Several years ago, we had a bush that had white all over it. It did not come off when touched. I just figured it was a fungus of some sort, but it may have been this issue. The area was overgrown with weeds, so we took care of those and cut the bush back to the ground. It grew back just fine, so maybe all those weeds had something to do with the soil condition.

    1. We have a large hedge made up of a number of plants all are healthy a season ago a couple of small new growth stems had white leaves and stems I pruned it out leaving a few leaves not wanting to make a small hole in hedge however now less than a year with the new growth season it has spread over a square meter worried it will not only continue on this plant but continue to others inline this is first time post

  3. It might be worth collecting a soil sample and having the local Agricultural Extension office test it, sometimes they do this for free.

  4. Bought malpighia c recently about a week ago and it was in the shade there. The nursery guy said I cd keep it in the sun but nowleaves turning white. Wonder if it has anything to do with the Indian June summer sun

    1. Amulyajit Kaur, I’m sorry I don’t know the answer to your question as I am unfamiliar with your climate and Malpighia.

  5. I’ve got a few plants in my yard turning white front & back yard I’m curious as to why they are turning, I havent been here but a year soooo….I’m not familiar with what grows here really

  6. I found my first all white privet 4 months ago in red clay in west central Georgia it was about 4 inches tall. I could barely get it out of all the interlocking roots. I brought a pot with miracle gro with me. It has taken very well and is about one foot tall and absolutely beautiful. My favorite plant. I don’t understand how it survives without chlorophyll.

  7. in my land there is fruiting jack tree.it’s fruit bearing part is normally green .other part of that tree leaves and stems are white. Reading after I also suggest insufficient of chlorophyll

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