It was my first avocado tree’s first winter when a couple leaves started getting yellow veins. Oh no, what disease was this?
I sent a photo to a seasoned avocado grower and he wrote back, “This is leaf senescence. The leaf is just dying naturally.”
With this post, I hope to calm your worries or clue you in when the leaves on your avocado tree take on unexpected looks.
This is a small gallery of photos of avocado leaves along with explanations of why they look the way they do. Learning to read the leaves of your avocado tree can help you care for it, or just relax and appreciate its stages of life.
Let’s start from the beginning.
New, red avocado leaves
Don’t let the red shock you. While these are among the reddest new avocado leaves I’ve ever seen (they’re on a seedling tree), all new avocado leaves are reddish. That’s just the way they grow (even in the wild).
Adolescent, lime green avocado leaves
. . . with mature, forest green avocado leaves
As the new, red leaves age they become light green and then deep green once mature.
If all is healthy with the tree and the soil below, then the leaves’ color will be uniform, not blotchy.
Old, yellowing avocado leaves
But at the end of their lives, avocado leaves begin to yellow, starting with their veins. The look could alarm you, as it alarmed me. The above photo shows dying (“senescent,” say the botanists) leaves on a Fuerte avocado tree.
These leaves on a Reed avocado tree are farther along in the aging process. They will drop any day now. This is their natural end.
So . . . from red to lime green, to forest green, to yellow: that’s the colorful cycle of life for an avocado leaf.
Yet things can go wrong along the way. And when they do, avocado leaves sometimes turn color but other times pattern, shape, or size.
Avocado leaves attacked by persea mites
That’s the blotchy yellowing on the top side of an avocado leaf when the tiny pest called persea mite has been feeding on it, but the better indicator is underneath.
Along the veins you’ll see dead spots where the mites have gathered and done their damage. (See this page for information on managing persea mites.) Noting this pattern helps to distinguish persea mite damage from other leaf stresses, such as when temperatures get too cold.
Mottled, cold-damaged avocado leaves
Cold damage forms little dead spots between the veins and all over the leaf. There’s no yellowing, and the spots are dark brown. Some people refer to it as bronzing. It’s a mottled, pixelated look that comes from nights that are too cold for comfort but not so cold as to kill the whole leaf.
Avocado leaves killed by cold, frost
If the temperature gets low enough, then leaves start to die. Young leaves like these are most vulnerable. After a frost kill, they appear black and curled; they look burned, ironically.
(For tips on preventing this, see my post “Protecting avocado trees from cold.”)
Bleached, sunburned avocado leaves
These leaves have actually been burned. At first they bleach to a yellow like the leaf in the lower right, but if the sun and heat is too intense, then they brown and die. Temperatures usually need to be well over 100 degrees to cause damage to the leaves of a healthy, well-watered avocado tree, in my experience.
Wilting, dull, thirsty avocado leaves
When avocado trees are thirsty or stressed because of extremely high heat their leaves droop, sag, wilt. The leaves of citrus trees cup and roll, but avocados do the opposite.
The above photo shows a young Sharwil avocado tree that is signalling thirst. I took the picture, then I watered it, and then I returned fifteen minutes later and took this photo:
Scroll back up and down to compare. After watering, the leaves rapidly became turgid, stiff, and shiny. When you read these leaves, you read hydrated, happy.
A little drooping from momentary thirst is no big deal. Worse for avocados is leaves drooping from constant soil saturation.
Drooping, pale, overwatered avocado leaves
This tree has been watered too often, and because of that its leaves are showing this sign. It’s strange that both not enough water in the soil and constant water in the soil show up in the leaves similarly, but it’s true. The main difference is that when you water a thirsty tree, it perks up.
Now here’s the most common ugly avocado leaf we see every fall and winter:
Avocado leaves with tip or margin burn from chloride salt in irrigation water
You shouldn’t see many of these leaves on your tree in spring through summer. They appear in fall once the chloride in the irrigation water that we use in Southern California has accumulated in the soil and tree. (It can also be partly due to not watering enough.) The leaf burn gets worse through winter, and then the tree sheds the burned leaves and replaces them with new ones in spring.
(More on this: “Avocado leaves turning brown? Here’s why and what to do.”)
On the other hand, here in the spring you’ll see . . .
Avocado leaves chewed by bugs
To find out who is doing the munching (it might also be slugs, Fuller rose beetles, grasshoppers, and more), check the tree with a flashlight at night. That’s when most critters chew avocado leaves.
(Also see my post “Who is eating holes in your avocado leaves?”)
Some avocado leaves can look as if they’ve been affected by a pest or disease or stress when the fact is that they can’t help it — they look funky by nature.
Wavy leaf margins on avocado leaves
The leaves of all avocado varieties look as unique as their fruit. The above leaves with undulating edges belong to my Pinkerton tree, but Sir-Prize and Nimlioh can have similarly wavy margins.
Upturned, cupped, taco-shell shaped avocado leaves
Another set of avocado varieties has leaves that are often folded up like a taco shell. The above photo shows leaves on a Holiday, but you’ll find the leaves of Lamb doing the same pose.
What could it mean if leaves in one part of the tree look different from leaves in another?
Look closely at this photo and you’ll see that the larger, greener leaves on the left all emanate from a branch that is attached to the trunk way down low — below the graft union.
(See my post “Your fruit tree is grafted — Why? And so what?”)
Usually, you’d want to cut off such a rootstock sucker immediately, but this is a friend’s young Fuerte tree, and I proposed using them to graft on additional avocado varieties instead. The tree now has branches of Reed and Lamb growing on it. It has become a three in one. It will have three sets of different-looking avocado leaves on the tree plus three sets of different avocado fruit. Is that making lemonade out of lemons?
There are many other looks to avocado leaves, but let’s end with the reality that most of the time leaves show a combination of characteristics. Here’s an example you can quiz yourself on. What is happening with this avocado leaf?
Why the yellow? Why the dots? Why the burned tip?
You might also like to read my post: