The Secret of Changing Tree Colors

In late September and early October, the trees in our yards, parks and forests begin to herald the arrival of autumn: hitherto clothed in green, they suddenly take on dazzling hues – yellows, oranges, reds and purples. So it’s a good idea to take advantage of a fine autumn day to take a family outing to the countryside, and enjoy the magnificent scenery created by the changing colors of the trees.

But don’t delay! The best of the fall color spectacle in our region, one of the richest in the world, lasts only eight to fifteen days, depending on the temperature. Strong winds, driving rain and extreme frosts shorten the display, while fine dry days followed by moderately cool nights prolong the pleasure to the maximum.

Photo: Mohan Reddy

Autumn Colors: A Natural Phenomenon

But where do these brilliant colors come from? We often imagine that leaves turn colorful in autumn, but in reality it’s more a case of fading. The yellow, red and orange were already there, but were masked by the green pigmentation of chlorophyll. During the summer, chlorophyll works to absorb the energy of light rays and transform them into sugars (photosynthesis), which are then transported to the branches, trunk and roots to serve as reserves. However, when night-time temperatures remain below 7? (45?), as is the case in autumn, the sugars become trapped in the leaf and their excessive accumulation destroys the chlorophyll. It’s only then that the green color disappears, and the other pigments surface, briefly, to fill us with wonder.

Is It Because of Frost?

And what about the popular belief that frosts cause autumn coloring? There have been years when trees began to take on their autumn colors in our region, at the end of September, but most areas had not yet experienced a frost. On the contrary, the brightest colors appear when the days are warm and sunny, triggering the production of a good quantity of sugars, and the temperature always drops below 7°C (45°F) at night. Extreme cold, on the other hand, causes the leaves to die, turn brown and dull and soon fall from the tree. So, for the best autumn colors, we’re hoping for a sunny autumn with cool but not too cold nights.

Photo: Marko Klaric

If Canada is so colorful, it’s because of the mix of species in its forests. In fact, the main component of southern Quebec’s forests is the sugar maple, a tree whose autumn color is second to none. Its leaves quickly turn to various particularly fiery shades of red, yellow and orange, and remain on the twigs longer than many others. It’s the combination of this tree with other typical Quebec forest trees – including the red maple, with its pinkish-red leaves; the vinegar tree, scarlet; the ash, purple; and the birch, golden yellow – that gives the panorama all its brilliance. And the occasional pine or spruce, which maintain their dark green coats all year round, will only serve to bring out the vivid colors of the warmer trees.

What to Plant for Beautiful Colors in Your Yard?

Autumn color is often the last thing on our minds when choosing plants to beautify our grounds. The proof is that our cities are adorned with trees and shrubs that are either of little interest in autumn (crabapples, caragana, honeysuckle, etc.) or remain green until the best show is over (Norway maples, European lindens, etc.). So it’s in the countryside, not the city, that autumn colors are at their most vivid.

Nonetheless, several species with attractive autumn coloring deserve our special attention as ornamental trees or shrubs, while offering plenty of appeal in other seasons too. Here’s a list of some of these plants:


Common nameBotanical nameZone
Allegheny ServiceberryAmelanchier laevis3b (4 to 8 USDA)
Paper BirchBetula papyrifera2 (2 to 6 USDA)
Scarlet OakQuercus coccinea4 (5 to 9 USDA)
Pin OakQuercus palustris4 (4 to 8 USDA)
Red OakQuercus rubra4 (4 to 8 USDA)
Mountain MapleAcer spicatum2 (2 to 7 USDA)
Sugar MapleAcer saccharum4 (3 to 8 USDA)
Amur MapleAcer tataricum subsp. ginnala2b (3 to 8 USDA)
Red MapleAcer rubrum3 (4 to 9 USDA)
Tatarian MapleAcer tataricum2b (3 to 8 USDA)
White AshFraxinus americana3b (3 to 9 USDA)
Blue AshFraxinus quadrangulata3b (4 to 7 USDA)
Green AshFraxinus pennsylvanica2b (3 to 9 USDA)
Maidenhair treeGinkgo biloba4 (3 to 8 USDA)
Ohio BuckeyeAesculus glabra2b (3 to 7 USDA)
European larchLarix decidua3b (2 to 6 USDA)
TamarackLarix laricina1 (2 to 5 USDA)
HackberryCeltis occidentalis4 (2 to 9 USDA)
American aspenPopulus tremuloides1 (1 to 6 USDA)
Hop TreePtelea trifoliata3b (4 to 9 USDA)
Mountain AshSorbus sp.4 (3 to 6 USDA)


Common nameBotanical nameZone
ServiceberryAmelanchier canadensis4 (4 to 8 USDA)
SmoketreeCotinus coggygria4b (4 to 8 USDA)
BearberryArctostaphylos uva-ursi 1 (2 to 7 USDA)
Tatarian DogwoodCornus alba2 (3 to 7 USDA)
Bloodtwig DogwoodCornus sanguinea4b (4 to 7 USDA)
CotoneasterCotoneaster apiculatus4b (4 to 7 USDA)
Winged Spindle TreeEuonymus alata3 (4 to 8 USDA)
European SpindletreeEuonymus europaeus4 (4 to 7 USDA)
Golden CurrantRibes aureum2 (3 to 7 USDA)
Common Witch HazeHamamelis virginiana4b (3 to 8 USDA)
NinebarkPhysocarpus opulifolius2b (3 to 8 USDA)
Fragrant SumacRhus aromatica3 (3 to 9 USDA)
Smooth SumacRhus glabra2b (3 to 9 USDA)
Staghorn SumacRhus typhina3 (3 to 8 USDA)
ViburnumViburnum sp.2b-4 (2 to 8 USDA)

Larry Hodgson published thousands of articles and 65 books over the course of his career, in both French and English. His son, Mathieu, has made it his mission to make his father’s writings accessible to the public. This text was originally published in Le Soleil on October 7, 1989.

Garden writer and blogger, author of 65 gardening books, lecturer and communicator, the Laidback Gardener, Larry Hodgson, passed away in October 2022. Known for his great generosity, his thoroughness and his sense of humor, he reached several generations of amateur and professional gardeners over his 40-year career. Thanks to his son, Mathieu Hodgson, and a team of contributors, will continue its mission of demystifying gardening and making it more accessible to all.

2 comments on “The Secret of Changing Tree Colors

  1. Kenton Vernon

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  2. Michael A. Lake

    The exploration of the secret behind the changing colors of trees in autumn is utterly fascinating! The vivid hues that emerge as chlorophyll fades, revealing the hidden pigments beneath, create a spectacular display that is so emblematic of fall. Larry Hodgson’s detailed explanation about how the accumulation of sugars, influenced by temperature, affects chlorophyll and subsequently unveils the stunning autumnal palette is enlightening. I’m currently working on a research paper exploring the psychological impact of seasonal changes on individuals and considering using a writing aid service to ensure my paper is well-structured and polished. Have you ever noticed a shift in your mood or behavior with the changing seasons, particularly when the trees begin to showcase their vibrant autumn colors? ??

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