Unless your silver maple (Acer saccharinum) is young or recently injured, don't be worried about its peeling bark. Mature silver maples naturally shed their bark, a process many people find attractive. While shedding is a natural process for a healthy silver maple, injuries can cause splitting and premature peeling of bark. Keeping your silver maple healthy and protected helps ensure any shedding bark merely adds to your tree's ornamental appeal.
Silver Maple Growth
Growing up to 36 inches per year, silver maples approach heights of 100 feet and have 50-foot spreads. Their roots grow aggressively, often wreaking havoc underground. Given a gentle breeze, the silvery undersides of silver maple leaves shimmer in sunlight with lovely effect. But if that breeze picks up to a forceful wind, the tree's weak branches and twigs often come tumbling down. The lack of branch strength results from silver maple's rapid growth rate. The faster trees grow, the weaker their structure. That rapid growth contributes to silver maple's exfoliating bark.
Why Bark Peels
As young silver maples mature, their thin, smooth bark thickens. The outer layers eventually stop actively growing. In the meantime, the tree continues to produce new bark layers underneath and to rapidly increase in size. That expansion forces the outer bark, now hard and inflexible, to develop furrows and ridges. It's similar to a balloon, which can only take so much internal pressure before something gives. In the case of healthy bark, only the outermost layer splits. The tree remains protected by healthy inner layers, while long strips of silvery outer bark shed and reveal reddish brown bark beneath.
Silver Maple Care
Keeping your silver maple in optimal health helps prevent unnatural peeling. Silver maples grow in U.S. Department of Agriculture plant hardiness zones 4 through 9, and do best in full to part sun with acidic soil kept consistently moist -- even wet. Moisture keeps silver maples healthy and hydrated during temperature extremes, and helps prevent sunscald from leaving young bark split and peeling away from wounds. Silver maples rely on their canopies of foliage to protect their bark from the sun. Never remove more than 20 percent of the canopy at any time.
Protection for Young Trees
Young silver maples lack the foliage needed to shade their thin bark. Extra protection is welcome when your young tree has a southern or southwestern exposure, or recent pruning leaves a tree's bark exposed. Whitewashing acts as a sunscreen until the canopy matures enough to do the work. Paint your tree's trunk from 1 inch below the soil line to at least 2 feet up the trunk. Use only white interior latex paint, mixed with equal parts of water. Never use enamel or exterior paint, even latex, or your well-intentioned efforts can cause irreversible damage to your silver maple tree.
- Cal Poly San Luis Obispo Urban Forest Ecosystems Institute: Silver Maple: Acer Saccharinum
- The New Sunset Western Garden Book; Kathleen Norris Brenzel, Editor
- University of California Statewide Integrated Pest Management Program: Maple -- Acer spp.
- University of California Statewide Integrated Pest Management Program: Whitewashing Trunks
- Iowa State University Extension and Outreach: Shedding Bark
- Martin Poole/Photodisc/Getty Images