Maple-leaf Viburnum

Maple-leaf (or Maple-leaved) Viburnum (Vibernum acerifolium) is spectacular this fall, with colors ranging from pale pink to deep magenta,

Maple-leaf Viburnum (Vibernum acerifolium)

often with washes of blue and purple.

Maple-leaf Viburnum (Vibernum acerifolium)

The combination of decreasing hours of daylight, the increasing length of darkness, and cool nighttime temperatures is nature’s signal that it’s time to prepare for winter. Plants gradually stop producing chlorophyll, which is responsible for the green color visible in the leaves during the growing season. The absence of chlorophyll reveals the colors of other chemical compounds present, like the yellows of xanthophylls, oranges of carotenes, and browns of tannins.

Many days this fall have been warm and sunny. Nights have been cool with temperatures often in the low to mid 40s (4 – 8°C). These conditions enable deciduous trees and shrubs to continue to produce sugars in their leaves during the day. Some of the sugars combine with minerals obtained from the soil to manufacture anthocyanins, the chemicals that cause the red, blue and purple colors in the leaves. The decreasing number of daylight hours combined with the cool temperatures signal the plant to stop nutrients from moving into the trees’ circulatory system as the leaves prepare to detach from the plant. These chemical compounds are trapped in the leaves, resulting in the colorful fall display.

Maple-Leaved Viburnum (Viburnum acerifolium) with fruit

Fleshy, dark blue, berry-like fruits called drupes accompany the colorful leaves. Each drupe contains a single seed enclosed by a stony casing or pit, like a peach. For many birds and other animals, the fleshy fruit is an enticement to dine in the coming weeks. Maple-leaf Viburnum and many other plants have evolved to produce such fruits in order to enlist animals as partners in dispersing their seeds. The animal consumes the fruit, passing the seed through its digestive system, and depositing the seed accompanied by other nutrients. White-throated Sparrows,

White-throated Sparrow

Cardinals,

Northern Cardinal

and Hermit Thrush, as well as chipmunks and squirrels are among those who consume the fruits and disperse the seeds.

Spring or Summer Azure butterflies may lay eggs on the flower buds of this and many species of viburnums, dogwoods and other shrubs.

Summer Azure

After hatching from the eggs, the butterfly’s caterpillars feed on the flower buds. That is, they do if they manage to avoid being eaten by a predator like a bird, a spider, or another insect.

Maple-leaf Viburnum (Vibernum acerifolium) in bud. Can you spot the two spiders waiting patiently for an unsuspecting caterpillar or other victim?

Plenty of flowers survive the feeding frenzy to provide a beautiful summer display. Several species of native bees, flies and other insects visit the flowers for nectar, providing essential pollination services that result in the fall fruits.

Maple-leaf Viburnum (Vibernum acerifolium) in flower. Look for the ants who are visiting the flowers for nectar. They would also be happy to find a caterpillar.

Maple-leaf Viburnum is a great alternative to the non-native, invasive Burning Bush (Euonymus alatus), which is often planted in formal landscapes for its fall foliage. Maple-leaf Viburnum offers an equally attractive, and more nuanced display. More importantly, it provides food and shelter for the insects, birds and other animals that share its territory.

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum is a woodland understory shrub native to the eastern United States, and Quebec and Ontario provinces. If you live within its natural range, go for a walk in the woods near you to see if you can spot it. Then think about adding it to your own landscape to guarantee a view of this gorgeous shrub.

Maple-leaf Viburnum (Vibernum acerifolium)

For more information on fall foliage colors, see Nutritious Fall Foliage: What Makes Fall Leaves So Colorful?

Resources

Capon, Brian. Botany for Gardeners. 2005

Cech, Rick; Tudor, Guy. Butterflies of the East Coast. 2005.

Glassberg, Jeffrey. Butterflies through Binoculars A Field Guide to Butterflies in the Boston-New York-Washington Region. 1993.

Illinois Wildflowers

Red Maple (Acer rubrum)

On Halloween, the Red Maple (Acer rubrum) outside our kitchen window gave up the ghost, so to speak. The leaves on the north side of the tree had been changing colors for weeks, but the rest of the tree remained stubbornly green. Overnight, the entire tree was awash in reds and oranges.

It’s the change in day length (or really night length) and temperature that signals deciduous trees and shrubs that it’s time to get ready for winter. They have to drop their leaves to protect themselves from damage that would be caused due to the heavy weight of winter ice and snow storms. As nights get longer and temperatures drop, these woody plants gradually slow and eventually stop replenishing chlorophyll, the substance that is responsible for the green pigment in their leaves.

Alexauken Wildlife Management Area, West Amwell, New Jersey

But what accounts for the array of colors that are revealed as the chlorophyll gradually disappears? The yellow, orange, red, purple, bronze and browns?

These colors reflect some of the same nutrients that are present in the plant-based foods we eat. Many of these chemicals were present throughout the growing season, but were masked by or blended with the green of the chlorophyll.

American Beech (Fagus grandifolia) Leaves in Spring

American Beech (Fagus grandifolia ) Leaves in Fall

The yellows are carotenoids, mainly xanthophylls, nutrients that help to reduce inflammation, boost the immune system and reduce tumor growth. They are present in yellow summer squash, beets, carrots, corn, peppers, green leafy vegetables, and many others. Xanthophylls help plants to absorb energy from the sun while protecting tissues against the sun’s intense radiation.

Alexauken Wildlife Management Area, West Amwell, New Jersey

Carotenes (another group of carotenoids) are responsible for the orange shades revealed in fall leaves. Beta-carotene is an anti-oxidant, visible in the orange color of foods like winter squash, carrots and sweet potatoes. They assist in photosynthesis, and help protect plant tissues from too much exposure to the sun’s rays.

American Hornbeam (Carpinus caroliniana) or Ironwood

Reds and purples are anthocyanins, nutrients found in foods like blueberries, blackberries, cherries, grapes (and red wine; yay!), purple cabbage, other purple-tinged greens like red leaf lettuce, some kale and swiss chard, as well as many others that show red or purple colors. Anthocyanins are antioxidants, with anti-inflammatory, anti-viral, and anti-cancer properties. Plants may also benefit from anthocyanin’s antioxident effect, and the dark colored pigments help protect from sun damage. They continue to manufacture these chemicals until the leaves fall.

Maple-leaf Viburnum (Viburnum acerifolium)

Brown and tan colors show the presence of tannins. They tend to be bitter or astringent tasting, and as a result discourage browsing by herbivores (plant-eaters) so they may provide some protection to plants. Tannins are found in foods like grapes, wine, tea, and chocolate, though, so you can see that this protection isn’t foolproof.

Spring Lake at Roebling Park, Abbott Marshlands, Hamilton Township, New Jersey

There is overlap and blending of colors based on the mix of chemicals in the leaves. These bright colors may also signal to birds that there is fruit available for consumption.

Yellow-rumped Warbler with Poison Ivy Fruit

These nutrients, along with others that are obtained from the soil, like calcium and potassium, break down and return to the soil as the fallen leaves gradually decompose. During this process, animals may still take advantage of the nutrients. Red-banded Hairstreak caterpillars, for example, feed on fallen leaves, especially those of sumacs, contributing to the process of decomposition, and the cycle of life for the next generation.

Red-Banded Hairstreak

A few days later, and the leaves on our Red Maple have almost all fallen. We’ll watch them gradually break down, nourishing the soil, and the plants and animals that rely on them.

Haul Road at the Trapp Family Lodge, Stowe, Vermont

Resources

http://science.jrank.org/pages/5303/Plant-Pigment-Carotenoids.html

http://www.usna.usda.gov/PhotoGallery/FallFoliage/ScienceFallColor.html

The Natural Web

Exploring Nature's Connections

Tag Archives: Maple-leaf Viburnum

Nutritious Fall Foliage: What makes leaves so colorful?

Share this:

Like this:

Share this:

Like this: