Colonnade, or columnar, apple trees grow only to 8-10 feet in height. Selected for small gardens or even patio containers, colonnade apples bear fruit on short horizontal branches. Many growers keep the width of the tree less than 2 feet across by careful pruning. Thinning branches and blossoms also enhances the quality of this dwarf apple tree's fruit crop.
Pruning Colonnade Apples
Remove any fruit which sets on the tree during the first season. Allowing apples to mature the first year after transplanting limits the tree's adjustment to its new surroundings. By the second year the tree's root system should be strong enough to support a small crop.
Clip off any branches or sucker shoots growing below the graft union. Fruit borne by the colonnade rootstock does not match the variety of the grafted section. Sucker shoots from the rootstock will quickly overtake the grafted portion of the tree if not pruned away. Don't wait for the tree to go dormant to remove suckers. Summer sucker growth diverts nourishment from the grafted scion.
Remove any dead wood in late winter during the colonnade apple tree's dormancy. Clip broken branches back to a main fork or remove them completely by trimming back to the trunk. Cut branches back to the branch collar--a ring of tissue at the junction of branches or the connection to the trunk. Don't injure the collar.
Prune to control the width of the tree by snipping the tip of horizontal branches about a foot from the trunk. Select fruiting branches with healthy side spurs and prune out smaller branches which compete for space. Cut off any vertical sucker shoots just above the branch collar.
Control the size of the harvest by thinning fruit after it sets on the tree. Late frosts or pollination problems often naturally limit the apple crop, so don't thin blossoms. Let more apples set on the stronger lower section of the colonnade apple than on the weak upper portion.