why has my elephant ear suddenly turned yellow?

Question

One of my three elephant ears on my deck in Brooklyn(only a mile from Stack Exchange HQ) has suddenly turned yellow. I had some yellowing on it's sibling earlier in the year, which I diagnosed as excessive water and corrected. The elephant ears are originally from Costa Rica according to the nursery I purchased them from.

However, the plant in the picture was growing fast and green until 3 days ago when I practically bleached. We had a very wet week with thunder showers, then much high temperatures and more sun. So I would diagnose it as too much sun, except its neighbor is green and happy. there are two environment differences between the two elephant ears: - different pots so slightly different soil and drainage - the green elephant ear gets more shade from the yellow elephant ear, and a royal palm.

1. is the yellowing an absence of chlorophyll? If so, how does excessive sun reduce chlorophyll?
2. would excessive sun yellow the elephant ear in a few days?

Thanks

Jeff

Answer 1

There is one glaringly obvious problem: the pot it's growing in looks way too small, especially as it's sharing space with a fuchsia and a croton. Elephant's ear is a large plant and will cope with being put straight into a 36inch pot on its own when you bring it home from the nursery (unlike most other plants). It's hard to be sure, but it looks like the container that houses the other one is larger, though possibly not large enough either, over time. I'm assuming there are drainage holes in the pot with the sickly one.

Obviously, you've mentioned too much sun as an issue, but it doesn't seem to be that because the other one looks okay, though it's possible this one gets a little more sun. The problem currently is, the plant was able to grow, but only to a certain size, and as the others grew, there was less and less room for its roots and increasingly less water to share between them, until eventually, its unable to cope and starts ditching its older leaves in order to survive. I would find a larger pot and pot on into that using fresh potting soil, asap. If you think it does get too much sun, then place in a different position, after repotting. Info here http://homeguides.sfgate.com/elephant-ears-pots-95332.html

Answer 2

I don't have an answer for

how does excessive sun reduce chlorophyll

But I hope it could help:

Regards the second point, I don't have a source for that, but I would say that a lot of thing can affect a planet in a matter of days - from the simple fact the a few days of anything can harm/benefit a plant. A few days with obsessive watering or absence of it can kill a planet, and a few days of good conditions can heal a plant.

The elephant ear does need light, but not full sun. Too little sunlight can cause yellowing (as your planet is experiencing):

Here's some more information about the yellowing:

^{Emphasis add by me.}

Can elephant ears grow in full sun?

Full sun is not ideal for most elephant ears-they grow best in bright, but indirect sunlight. Too much sunlight can burn elephant ear leaves, while too little sunlight can cause yellowing. There are certain varieties that can tolerate full sun.

Why are my elephant ears turning yellow?

If the leaves of your elephant ear are turning yellow it could mean there is a problem. Try changing the amount of sunlight or water the plant gets and possibly apply a fertilizer. Alternatively, the plant may be going dormant for the season. Cut back the yellow leaves and wait for it to return next spring.

Answer 3

i read on numerous sites that elephant ears shed the oldest leaves every time a new leaf comes out because it can only sustain a certain number of leaves on the stem. look to see if the leaf that is turning yellow is coming out of the lowest location on the stem. if so, this is natural.