Maple-leaf (or Maple-leaved) Viburnum (Vibernum acerifolium) is spectacular this fall, with colors ranging from pale pink to deep magenta,
often with washes of blue and purple.
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.
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,
and Hermit Thrush, as well as chipmunks and squirrels are among those who consume the fruits and disperse the seeds.
In early summer, Spring or Summer Azure butterflies may lay eggs on the flower buds of this and many species of viburnums, dogwoods and other shrubs.
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, an ant or other parasitic insect.
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 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 is a woodland understory shrub native to the eastern United States, and Quebec and Ontario provinces. If you live within it’s 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.
For more information on fall foliage colors, see Nutritious Fall Foliage: What Makes Fall Leaves So Colorful?
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.