I have 3 clumps of serviceberries with about 4 mature stems each spaced about 10 feet/3 m apart. They are about 15 feet/5 m high and only have foliage on the top third of the bushes. I would like 10 foot/ 3 m high bushes and the appropriate lower leaves that would go with that. Sort of a loose hedge style thing. How can I go about pruning the serviceberries to get this, or is this sort of thing even possible?
Thank you for your question for Toronto Master Gardeners concerning your serviceberry.
Serviceberry (Amelanchier spp.) is a small deciduous tree or shrub with attractive white spring blossoms, attractive red leaves in the fall as well as producing edible fruits. This plant is known by a variety of common names including shadblow, shadbush, juneberry and saskatoon.
The answer to your question is yes, your Amelanchier can be pruned to induce its natural production of offshoots. However, without the cultivar name (there are approximately 8 varieties), it is difficult to determine how plentiful the production of shoots will be. Perhaps the nursery where you originally purchased the shrubs may be able to provide the cultivar name.
Pruning cuts trigger a physiological response in plant cells which affects bud dormancy and branching habits. It will take at least three years to get the plants to have a bushier habit. Before you begin, take a good look at the plant and select about one third of the branches, divided evenly all over the plant. Cut the chosen branches back by 1/4 to just above an outward facing bud. The following year you can then remove half the branches that were left the last time, and in the third year all the remaining branches can be tackled. The best time to prune is when the plant is fully dormant in late fall.
Some key points to keep in mind : use sharp appropriately-sized bypass pruners to prevent bruising. Make sure to sterilize pruners with each cut, apply water and fertilizer in spring, and regularly check your plant for insects and diseases, such as powdery mildew, so that these may be treated early.
The Alberta government has an excellent fact sheet on Saskatoon Berry Production which discusses pruning in detail. See pages 45 to 59 and Table 5 pages 57 to 59. Pruning Serviceberry also has an excellent description on rejuvenation pruning.
Lastly, the Toronto Master Gardeners answers questions to residents in the Toronto area. You may wish to contact the Master Gardener group in your area here
Good Luck with your serviceberries.