Cultivated serviceberry trees include the downy serviceberry (Amelanchier arborea), which grows in USDA zones 4 through 9, and the common serviceberry (*Amelanchier canadensis), which grows in zones 4 through 8. All varieties are deciduous, so it's best to plant a young tree in early spring, just before it puts out new growth. You can also plant in early fall, while the soil is still warm and new roots have time to grow. Summer planting is also possible but more risky, because hot weather can stress the tree and heighten shock from transplanting. If you must plant in summer, keep the tree well watered.
Most species are medium-sized and grow at a modest rate -- for example, the downy serviceberry is about 10 feet tall after five to 10 years, eventually becoming 25 feet tall and 15 feet wide -- so allow about 7 or 8 feet of free space around the tree, a spacing that works for any species. Fruit drop can cause messy litter, so serviceberry may not be suitable near a patio or similar area.
The serviceberry tolerates a variety of light conditions, but a spot that gets filtered sun through a canopy of taller trees is ideal. It also does well in any type of garden soil, provided it's well-drained.
This tree is tolerant of dry spells once established, but grows best with a regular supply of moisture. To provide it with adequate water, check the soil 4 to 8 inches deep every week and water whenever it feels dry; run a trickling hose at its base for several hours, to ensure you water deeply.
Add a few inches of organic mulch under the tree's canopy to conserve soil moisture, but keep it back from the trunk to avoid fungal problems.
Pruning and Fertilizing
A young serviceberry is naturally shrubby and multi-stemmed, and doesn't require pruning for the first three years, except to remove damaged or broken branches. But you can shape it into a single-trunked tree by removing all but one strong, straight stem at planting. In later years, prune back a few branches to encourage new growth, but leave some older branches because fruit forms on 2- to 4-year-old stems. Prune when the tree is dormant and wipe your blade with rubbing alcohol between cuts to prevent spread of plant disease.
Don't fertilize a serviceberry until the second season, then feed every spring when new growth first appears. Use a balanced fertilizer such as a 16-16-16 formula, mixing 1/2 pound into the soil under each 100 square feet of area under the tree's canopy, but check your product label for further directions. Water thoroughly after fertilizing.
Fungal disorders might become a problem for a serviceberry it it's grown under especially wet conditions or where air circulation is poor. For example, witches' broom causes black fungal growths on leaf undersides, leaf blight can cause black spots on leaves, while fire blight causes wilting and die-back of branch tips. Prune damaged branches, making cuts at least 4 inches behind the diseased branch portion. To prevent these problems, water the tree at its base to keep foliage dry and clear away debris regularly.
Pests that might attack leaves and slow growth include worm-like larvae that are greenish-back or form cocoons on leaves; these should be hand-picked where possible. Some boring insects can also cause damage, but healthy trees that are fertilized and watered regularly are less susceptible. Aphids, tiny green insects, and microscopic mites that produce webs on leaves can also damage foliage. Control aphids and mites by spraying at two-week intervals with insecticidal soap, diluted at a rate of 5 tablespoons per gallon of water.