Flowering Spurs on Apple Trees

What Are Spurs?

• Spurs are the terminal ends of old wood on a fruit tree. They are mixed buds that produce leafy shoots and fruit. When the leaves are produced, a flower grows under each stem and eventually become a fruit. Spurs can grow upon spurs, which creates a branched spur system. When this happens, fruits are too close and fewer apples form. Spur-type trees tend to be dwarfed and are actually mutations of standard-bearing trees.

Flowers on Apple Trees

• Spur-type apple trees tend to fruit earlier than non-spur, but they produce less foliage and are slower-growing. The flowers are fully developed and open just as the leaf buds begin to unfurl. Each spur or terminal shoot produces auxin which is a plant hormone. One of the things auxin affects is the formation of flower buds, which is minimized when auxin is present. Greater flowering occurs when the terminal ends are removed. This prevents shoot growth, which auxin promotes, but enhances flower production.

Pruning in Winter

• The purpose of pruning spur type trees is to encourage the formation of new spurs, remove old spurs and encourage shoot growth. The bearing shoots at the end of the branches should grow 12 to 18 inches per year. Much of this growth is removed in winter to promote bushier growth in the first three years of an apple's life. Flowering spurs develop at cut sites as a response to the weakening of vegetative growth. Removing some of the dead or unproductive wood on the interior of the tree will also encourage flowering spurs because of the increase in light.

Pruning Flower Spurs in Summer

• Apple blossoms are simple white to pink flowers that swell after pollination and begin to form the fruit. Pruning adversely affects fruiting to some degree when spring flower spurs are removed in the winter pruning. Branch spurs may be reduced in number which is healthy but the majority of flower spurs need to remain until summer. Removal in summer gives the plant time to produce new spurs for the following season. Winter pruning can actually result in the pruning removing the fruiting spurs, which is not desirable.