Cause of color change in fall leaves: Fall color in leaves is driven by three pigments: chlorophyll, carotenoids and anthocyanins. Chlorophyll, the green pigment, is crucial for photosynthesis during the growing season. In the fall, the day length shortens and temperatures cool, which triggers plants to prepare for winter by reducing chlorophyll production.  When chlorophyll production stops, the green color fades, revealing the yellow and orange hues of carotenoids. Also, anthocyanins, which give red and purple colors, are produced in late summer and early fall as photosynthesis slows down. Environmental factors, like warm days and cool nights enhance anthocyanin production, leading to vibrant colors. Not every shrub species produces carotenoids or anthocyanins in equal quantities. This is what creates the difference in fall color from species to species:

Intensity and duration of leaf color varies with each season: Weather conditions in early fall largely determine the intensity and duration of leaf color. The best fall color shows when days in early fall are sunny and mild, and nights are cool but remain above freezing. Long periods of cloudy, rainy weather or a hard freeze in early fall will mute fall colors. 

Obtaining a fall shrub fireworks display: Continue to show off your beautiful garden in the fall, after the summer blooms have disappeared, with some of these shrubs:

• Chokeberry: Black chokeberry, like the "Viking" variety, yields spectacular, bright red autumn foliage and is known for less suckering, compact growth and large berries after white spring flowers. Note: The chokeberry is considered a good substitute to the burning bush, which is now considered a restrictive noxious weed in Minnesota. https://extension.umn.edu/identify-invasive-species/burning-bush

• Redosier Dogwood: The versatile, fast-growing dogwood reveals bright red or yellow stems as the season progresses. Some varieties, like the 'Flaviramea', bring red-purple fall foliage, too.

• Hydrangea: Choose from many Minnesota hardy hydrangea shrubs that explode with enthusiasm in the summer months and, then, grant us all an encore of mauves, greens and golden-brown flower heads in the fall. ‘Limelight' hydrangea starts with a lime-colored summer display and ends with deep pink as it ages.

• Staghorn Sumac: This native shrub exhibits bright reds and oranges in the fall and works well in a larger area. ‘Tiger-eyes’ sumac is a smaller selection of staghorn sumac, requiring less space in your garden. It boasts chartreuse green foliage in the spring, yellow foliage during the summer and fiery orange foliage in the fall. 

There are many more shrubs that provide a pleasing color display in the fall. Maximize the color blast of your Minnesota garden with the endless fall color shrub varieties listed in the sources below. 

SOURCES:

1. https://www.extension.iastate.edu/news/yard-and-garden-fall-color-faq

2. https://yardandgarden.extension.iastate.edu/how-to/trees-and-shrubs-great-fall-color

3. https://extension.umn.edu/trees-and-shrubs/black-chokeberry

4. https://extension.umn.edu/identify-invasive-species/burning-bush

5. https://extension.umn.edu/trees-and-shrubs/redosier-dogwood

6. https://extension.umn.edu/trees-and-shrubs/serviceberry

7. https://extension.umn.edu/find-plants/trees-and-shrubs

8. https://extension.umn.edu/news/growing-hydrangea-minnesota

9. https://trees.umn.edu/tiger-eyes-sumac-rhus-typhina-bailtiger

   
   

Photo Credit: Mary Gadek (1,2), University of Missouri, Integrated Pest Management (3)