Why Do Leaves Change Different Colors on the Same Tree

Today is rainy, windy and 49 degrees. The nights have been 37 degrees. So, did you ever wonder about the changing leaves in regards to the weather? In regards to daylight?

We all probably learned it in school, but most likely don’t remember the specifics. The picture to the left was taken of my Redspire Pear today. Cold, windy  and rainy.

For many years, scientists have tried to fully understand the changes that happen to trees in the Autumn.

As the days grow shorter and the nights grow longer, biochemical processes in the leaf begin to paint the landscape awash with  glorious color.

These chemicals are responsible.

  • Chlorophyll for greens
  • Carotenoids for orange
  • Xanthophyll of the Carotenoid group for yellow
  • Anthocyanins for reds and purples
  • Tannins for brown as a waste product

The image below was taken on Garden Bloggers Bloom Day, a balmy warm day in the 60’s with temperatures dropping at night to the mid 40’s.  Only three days between these two images passed. Does this not make you wonder? Even the same roses are present.

So what happened besides the weather change?

And why does one individual tree, like my pear above have all these colors during this  one season?

Because combinations of these pigments give us a huge range of color variation, just like an artist mixing paint on a canvas.

It depends on the quantities of pigments, in this case chemicals,  being mixed. It depends on the weather and time of the season too. The leaves were gathered only for the post Gone But Not Forgotten on November 10.  One week ago. A lot has remarkably  happened in a week.

Here is the Breakdown

The red pigments of the anthocyanins protect leaves from the sun, giving some species extra time to absorb their essential leaf nutrients. As chlorophyll starts to exit the leaves, anthocyanins are being created to get the leaves additional time to unload the excess nutrients. Anthocyanins are a result of excess sugars within the cells and in combination with bright light, produce red pigment. Most anthocyanins are present only in Autumn. So that is why I saw the tree turning red at first, only to go full-blown yellow as the days lengthened and the rains came. My pear needed more food supply, so it went into high gear.

The carotinoids are present in the chloroplasts of the leaf cells during the entire growing season.  But they are covered up by the abundance of chlorophyll in summer.   As the chlorophyll is prevented from being produced, all the other colors start revealing themselves.

Bright light you say, when the nights are getting longer. Hum. The brightest Autumn colors are seen when the summers are dry and Fall has bright and sunny days with cooling nights in the lower 40’s. This is when some trees start making the anthocyanins. Not all trees make this chemical though. Many older European trees do not. In other trees, it is bred into them.

And without excess fresh water to renew it, the chlorophyll begins to disappear.  The veins in the leaves start to close and cut off the water supply and trap the sugars. See my leaf image above as the veins turn red in the green leaf. This is the tree prolonging nutrient uptake with the production of anthocyanins.

There is so much detail to see if you just have a look. I picked the green leaves off the tree a week ago. You can see them changing to red. Then the yellows and oranges begin to appear after some have changed to red. Therefore all colors are present on my tree at once.

Different trees change at different times during the season, though.

US Forestry Service

Certain colors are characteristic of particular species. Oaks turn red, brown, or russet; hickories, golden bronze; aspen and yellow-poplar, golden yellow; dogwood, purplish red; beech, light tan; and sourwood and black tupelo, crimson. Maples differ species by species-red maple turns brilliant scarlet; sugar maple, orange-red; and black maple, glowing yellow. Striped maple becomes almost colorless.

Leaves of some species such as the elms simply shrivel up and fall, exhibiting little color other than drab brown.
The timing of the color change also varies by species. Sourwood in southern forests can become vividly colorful in late summer while all other species are still vigorously green. Oaks put on their colors long after other species have already shed their leaves. These differences in timing among species seem to be genetically inherited, for a particular species at the same latitude will show the same coloration in the cool temperatures of high mountain elevations at about the same time as it does in warmer lowlands.

This list of trees and color characteristics is from here. Interesting stuff, a bit technical, but good to know. It is a much more detailed explanation as to why leaves change color from the US Forestry Service. A place you can believe.

Leaves Fall Off

The bottom cells in the separation layer of the leaf form a seal between leaf and tree. The cells in the top of the separation layer begin to decay and break up. They form a break-line, and eventually the leaf falls from the tree.

If subjected to early frost, the trees will end their colorful display.

How About Those Evergreens

And what about evergreens like my Sparten Juniper behind the pear? What is different? Well, one difference is in that the needles are covered with a wax-like substance that prevents water loss. In the case of my concolor, the tree has a small surface size of individual, long, thin needles. Less  surface, less exposure. Also quantity plays a part. Needles have many neighbors, cutting down on desiccation by wind. The interior of the needle also contains their own type of antifreeze to prevent evaporation and allow water to move even in  winter. Now you know the principle behind antidesiccant. Coat em’ like a candle.

Color Recap

The colors you see in my leaves gathered last week are orange, yellow, red and green.

We all know the green is a result of Chlorophyll. The Reds are from the protecting anthocyanins.  Since carotenoid production is not dependent on light, the levels in the leaves are not diminished by the  shorter days. Carotenoids can be orange or yellow but most of the pigments found in leaves are yellow. Leaves with decent amounts of both anthocyanin and carotenoid will appear orange. Leaves with carotenoid but little or no anthocyanin will appear very yellow. If these pigments are not present, other plant chemicals also can affect leaf color such as tannins. Tannins are responsible for the brownish color of some oak leaves, for example.

Why are My Leaves Different Shapes on the Same Tree

The different shapes of the leaves are probably a result of the dry season we had. The alternating between dry spells with rain produced leaves smaller, stunted and misshapen, only to revert back to the expected shape of the pear leaf once moisture became plentiful.

About Garden Walk Garden Talk

I love to photograph, paint, draw, design, garden, travel the world, and pass on a few tips and ideas that I learned through experience as a Master Gardener and architect. I am highly trained in my field and enjoy my work each and every day. I garden in Niagara Falls, NY in zone 6-B. Find me at: http://gardenwalkgardentalk.com
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50 Responses to Why Do Leaves Change Different Colors on the Same Tree

  1. Missy says:

    So interesting. Thanks. I’ve leant something new. We have trees that produce red leaves as new growth which turn green as they mature. Maybe they have anthocyanins as well – that would explain the colour.

    • I actually never though about red leaves in spring, like on a Bloodgood Japanese Maple. You just take it for granted. What a good question. Since the chemical is a pigment agent and you have bright light in spring, it seems to make sense, but I am guessing this may not be the case. There has to be other factors involved. Since anthocyanins are produced to make other tree get a longer time for nutrient storage this is where it makes me think that since red leaves are naturally occurring in certain species, there is more to it. Also, like the Japanese maple, if the tree does not get enough sunlight, it starts to turn green. I will have to investigate. We need a tree specialist to weigh in here.

  2. Andrea says:

    I am new here, just joined Blotanical and still fidgeting on the how to’s. I am glad to have picked your post because you described the changes in pigments in a very layman’s terms and easy to understand. Autumn is a scene i dream to see in person but just not yet. We only have 2 seasons. It is not often to see posts which are like this. I am a plant physiologist and i know everything you said, but i learned it the hard way in school. It is nice to read it in as simple terms as you chose to, with very beautiful photos to go with it.

    • Maybe you can answer the previous question. It was a good one and needs some expert to answer.

      • Andrea says:

        Hi Donna and Missy, i am glad ONE provided the answer from my discussion in my post. I haven’t read the interchange of comments here as i forgot to have the feeds, hehe. She just informed me of the ongoing discussion. Donna, your post is very convincing just like coming from an authority, in fact you got me fascinated by your clear layman’s description. I cannot do that myself without any technical terms, which i might not be able to ‘laymanize’ properly.

  3. Christina says:

    Thank you so much for the excellent explanation for the wonderful autumn colours.
    You made everything very clear but I have a question. Why is it that here in Northern Lazio, Italy the oak leaves turn brown but stay on the tree until the following spring in the same way that beech leaves do in England?

    • When sunlight decreases, it signals the trees to close their veins to transfer. After color changes, the leaves drop, but not in the oak. The separation layer does not decay like in other trees, so the tree never fully detaches the dead leaves of the oak. As long as winter winds do not kick up, the leaves will remain affixed to the tree. They do eventually fall, when new ones start to replace them.

      My good friend is a tree grower, so I have learned a lot from him. You may want to check with your forestry service. They always have good answers. I am a Master Gardener, but we never learned this much detail in those classes. But it is a good place to check too.

  4. Karen says:

    Thank you for the excellent article once again, Donna. I did not know the science behind leaves changing color. Fascinating!

    • I have always love science. I was a biology major in undergraduate school. I was always fascinated by how things work and the building blocks of the body. I studied four years of science before going into architecture. My talents lie in design and art, and I was trying to deny my calling. It was definitely not time wasted. I gave me an appreciation for life and how much there is to know and understand.

  5. I learned this in Botany many moons ago, but I am glad to have a refresher as fall leaf color is one of my favorite parts of gardening–something I have deliberately planted for during the last 25 years. I just wish it lasted longer. How did you make your photo of the pear leaves? I am sure it is some special process. If you could send me an explanation or a link, I would really appreciate it. Carolyn

  6. Great information in this post Donna. It is a very good refresher course and we all need it nearly every year. Here I look out over a mostly naked landscape. ;>)

    • The pear is the last to lose its leaves in the whole neighborhood. Last year, it was still GREEN in JANUARY. I was so scared Gilbert would lose his tree top home when the ice hit. But we had a mild winter last year. Lucky Gilbert.

  7. This was a really informative post; I love botanic knowledge!

    • Thank you Susan. I love science and with past schooling, like to keep the info fresh. My friend the tree grower helps me out too if I ask something I am not sure of. That is why I have so many posts on trees. I use many different trees in my design work, and am always checking out all the info I can get on them.

  8. lifeshighway says:

    Great article and very well written. Are you a biology teacher in real life? Great pictures to illustrate your point too!

  9. Outstanding explanation! I think it’s so interesting how the older European trees don’t turn colors as readily. I was reading in The Brother Gardeners how very attractive trees like our Sweet Gum were to 18th century English gardeners because they lacked our brilliant fall color.
    Your Redspire pear is beautiful. I’ve been thinking about that one for me!

  10. patty says:

    I have come to realize I can count on you for some excellent information on trees. I do not know the answer to Missy’s question but it reminded me of roses and how their leaves start off red before turning green.

    • Thank you so much for your kind words. I am glad you read the comments too. Andrea and One helped a lot with Missy’s question, and I thanks them.

    • Andrea says:

      Hi Patty, i am a bit late in replying to yours but i will just join in, with Donna’s permission. I have a recent post explaining why young leaves are colored such before turning green. Juvenile red roses’ leaves are because of anthocyanins, which have protective functions for the still vulnerable young chloroplasts, which are green. http://www.abagillon.blogspot.com

  11. One says:

    Hi Donna, Wrt Missy’s question, this was mentioned in Andrea’s blog:
    “So most young leaves have reddish to purplish colors. These pigments are mostly anthocyanins, one of the pigments (YES) related to photosynthesis, which are directly happening in another pigments (green)called the chloroplasts. Anthocyanins serve as protective mechanism for the intense light intensity and UV to reach this still young chloroplasts. They serve as the umbrella or sun-block to avoid too much light stress. The technical term is photoinhibition. ”
    The above is extracted from the comment area of Andrea’s Post on New Growth, New Life. https://www.blogger.com/comment.g?blogID=5003023115854661475&postID=574331658308307826

    Btw, do those different chemical explain the different colors available on moon cactus?

    • Andrea says:

      Hi One, maybe the explanation for the moon cactus in your blog is different. Pls remind me which is the moon cactus, it is the one grafted to another one? Maybe i will reply to that in your post, because this is Donna’s. Hi Donna.

  12. Christine B. says:

    The problem with blog posts like this is they put the rest of us to shame. (Current reflections about the usefulness of my own blog content are tinged with chagrin and are therefore to be avoided.) I must content myself with thinking that someone has to set the bar low, why not me?

    And no wonder fall was a color dud this year: it rained 27 days straight!

    Christine in Alaska, low end of the garden bloggers bell curve

  13. TufaGirl says:

    You are a great teacher. Well said.

  14. Garden Sense says:

    Amazing transformation. Every year is an unfolding adventure. Aren’t you glad you have the photos to document it? Great information on the process behind the great colors we’re priviledged to enjoy.

    • I had lost many many photos when I lost a computer a while back. Many of my job photos are long gone. I had a back up but that too got fried, even with a surge protector! I am starting to take better care of my photos now that I have a blog. I do not keep the external drives plugged in. Before, it was not so tragic, but now I miss photos that I know are good examples and help explain my story. Bummer.

  15. I think that’s the clearest and most complete explanation I’ve come across for the leaf colour changes, thank you! I love your collection of different coloured leaves all from the same tree. The shear dynamism of Autumn is wonderful, it counteracts that sense of everything closing in and shutting down.

  16. Great post and highly informative. Nature is really fascinating, isn’t it?

  17. fer says:

    Great post! thanks for the information.
    This explains a lot, now I know why some damaged branches will turn colors even in summer. It also explains why my little maple has only changed in one single lead, it is so pampered it has all the water it needs.

    • I am glad to help. I love trees and use them a lot in my design work. I try to explain to clients what they are to expect with their new trees. Some trees are selected only for color and of course their massing in the scheme. Some clients winter in warmer climes, so tree section and bloom is really important to time when they return, so they don’t care about late fall color.

  18. So glad to help. Once you have some basics, you can always find out answers knowing the right questions to ask with a good place to start.

  19. I get excited about leaves in the fall, but unfortunately, I get a second batch of leaves from the oak tree in the back in late winter/early spring which means raking in two different seasons. Blech. Anyway, great post!

  20. debsgarden says:

    Excellent post with great information! I was just recently thinking about why leaves change colors. It is good to know the facts. I will have to study your post so I can remember. It seems that our leaves are turning a bit later this year for some reason, maybe because of our very warm September?

    • You are correct. The temps signal if a change occurs. Warmer, brighter days, with cooler nights in the mid 40’s. The fall brings the longer nights too. This is a major factor, but the temp must work with the program too.

  21. Layanee says:

    Between the gnomes, your discussion and explanation of color change is informative and enjoyable to read. No leaves left here. All is barren.

  22. Jennifer says:

    I love the gnome artwork on your blog. Do you use Photoshop to create them or are they hand done? Your blog posts are always brimming with good information. I really appreciate the effort that must go into them. Have a great weekend! Jennifer

    • Hi Jennifer,
      I use Photoshop and Painter, apps used for painting. I use a tablet with a pen stylus as a brush or airbrush. In both apps, you pick and mix your paint color as you would in traditional painting, then apply it in any way you want. Oil, watercolor, drybrush etc., I often mix the applications for desired effect.

      The stylus is pressure sensitive, so you can add as much water or paint to the brush as you like and apply it the same as with a traditional brush. You also ‘clean’ your brush if you want after each stroke. I paint often in acrylics and oils traditionally for presentation work or as gallery work, but to do it on the computer, there is no smell of turp or cleanup of paint. Plus, the best part is, I can do one of these in about 15 to 45 minutes, depending on the complexity. I can even put it on a ‘canvas’ if I want right on the computer. I just pick a canvas background, and the algorithms simulate the raised and lowered texture of the canvas. Same with oils. It gives a texture to the stoke. Then I could actually print it to a real canvas. Hope this answered your question. Thanks for your kind words too. Much appreciated.

      • Andrea says:

        You are so talented. I don’t even know how to edit with Photoshop, hehe. And your computer paintings are so awesome, i can imagine the more they would be in your true canvas! Envious, yes i do. Congratulations for having that gift.

  23. Wendy says:

    interesting post! Your garden is gorgeous. I’d like to see it in spring! I love that photo of the leaf collage.

  24. Cat says:

    Thanks for such a clear, consice explanation – I always learn something when I stop by your blog! I’m curious about the Japanese Maple color in the spring too. Mine are in shade to survive the Texas summers and the leaves go from red, to green, back to red again. The new growth in the late summer and early fall is red tinged with green. The whole process of the color changes is fascinating. Funny how I didn’t enjoy science so much as a kid but can really appreciate it so much more now as I can apply it to my passion for gardening.

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