When to Prune a Serviceberry Tree?

Species of the native serviceberry tree (Amelanchier spp.), widespread in many areas of North America, have many common names including juneberry, shadblow, shadbush, sugar pear, sugar plum, Indian pear and Saskatoon. Although serviceberries are commonly called trees, they are technically shrubs with multiple stems. The six most widely planted of the 26 named cultivars range from 6 to 18 feet high spreading just as wide.

Serviceberries grow within U.S. Department of Agriculture plant hardiness zones 3 through 10, though hardiness varies by species. For example, downy serviceberry (Amelanchier arborea) will grow in USDA zones 4 through 9, juneberry or Canadian serviceberry (Amelanchier canadensis) will grow in USDA zones 4 through 8 and Western serviceberry (Amelanchier alnifolia) will grow in USDA zones 3 through 10.

Water and Fertilizer

Keep the soil moist but not soggy during the growing season. To avoid fungal diseases, water at the roots, not with sprinklers.

Serviceberry care begins with planting a nursery seedling and following through with appropriate fertilizing and pruning as the plant matures. Scatter 4 ounces of 10-10-10 water-soluble, granular fertilizer in a circle 6 to 12 inches away from the base of the trunk of a newly planted seedling, and water well.

Apply fertilizer at the beginning of spring each year; when the tree starts forming buds, it's time to fertilize. In the second year of growth, increase the amount of 10-10-10 fertilizer to 6 ounces. Increase it to 8 ounces the third year of growth, and use 10 ounces for trees four years or older. Always water well after fertilizing.

Pruning

Prune serviceberry trees in early spring before new growth starts. The goal of pruning a serviceberry tree is to replace all the wood that bears fruit every three to four years and to have a plant that lets in air and sun, with a form that makes it easy to pick berries.

For the first three years: Prune diseased, damaged or dead branches flush with the ground.

After the third year: Prune from one-fourth to one-third of the stems, targeting stems that are weak and stems growing from the trunk close to the ground. Stems two to three years old yield the most berries; prune stems older than that. If you're trying to limit the height of a tree, prune stems more than 6 feet tall.

Insects and Disease

The incidence of aphids, beetles, mites and other usual suspects among insects that afflict landscape plants is low among properly maintained serviceberry trees.

Serviceberry trees are most often infected by two fungal diseases: Entomosporium leaf spot and cedar serviceberry rust. Both typically follow wet spring weather.

Entomosporium leaf spot begins as red spots on the leaves of lower branches. The spots work their way upward, infecting the leaves in the middle of the tree and then the top, expanding into large maroon blotches that can defoliate the plant. A severe infection can kill a tree.

Serviceberry rust, also called serviceberry hawthorne rust, may be caused by any one of seven Gymnosporangium fungi. Yellow to orange spots appear on the tree in warm, spring weather, first covering the undersides of leaves. The rust may eventually cover shoots and berries and defoliate the tree.

Mancozeb is the fungicide of choice for treating both fungal diseases. To treat, mix 3 teaspoons of mancozeb to 1 gallon of water, and add to the tank of a backpack sprayer. Spray foliage at the first sign of Entomosporium leaf spot or serviceberry rust, covering thoroughly. Repeat every seven to 10 days until berries set.