The Agent's Observations Feb 1998

The time is fast approaching when dormant pruning and training of ornamental shrubs, roses, shade trees, evergreens, fruit trees, grapes, and brambles should be completed. Annual pruning is done to keep plant material producing young growth where production of flowers and fruit are wanted. Generally fruit is produced on at least one year old wood (as is the case of peaches, grapes, and brambles) or two year or older wood (as is the case with apples and pears). Dormant pruning is best when completed before buds swell and open. However, pruning can be done through the flowering of fruit trees although competition with honey bees may be painful! Grapes may be pruned until small leaves are present, though they will bleed, but that is not damaging to the plant. Brambles and roses can also be pruned when small leaves are present. Generally pruning of flowering ornamental shrubs is done when flowers are spent. Deciduous shade trees (those that lose their leaves in the winter) and conifers are pruned when dormant. Evergreen shrubs can be pruned during early spring.

The first rule of pruning is to remove any dead, diseased, broken, rubbing, or parallel branches. A parallel branch is one directly above or below the desired branch and shades it out or is shaded itself. Also, remove any root suckers, water sprouts, or branches positioned low on the trunk. When making cuts do not cut through the branch collar. Cutting through the collar will cause poor healing and encourage disease (see illustrations). Generally pruning sealer or paint is not needed for most pruning cuts. In some cases, typically ornamentals, these compounds can aid in decreasing desiccation and disease, especially if large cuts are made. One example is fruitless mulberry which is susceptible to sooty canker disease.

The most critical time to train fruit trees is during the first three years from planting. The first dormant season select three to five limbs that are well spaced around the tree, with the lowest branch about two feet from the ground. This is the first whorl of scaffold branches and should also be well spaced up the tree trunk between two and four feet from the ground. Branches should be spread from the main trunk at a 50 degree angle using spreader sticks, ties, or weights. This will encourage good tree structure and early fruiting. When a one-year-old shoot is tipped, more growth will occur. However, if cuts are made into two-year-old or older wood, regrowth is much less. Thinning cuts are made at the base of shoots to remove them completely from a branch.

Apple trees are trained and pruned into a central leader, forming a tree that is pyramidal in shape. Peach, nectarine, sour cherry, and Japanese plum are trained and pruned as an open-center tree which looks like a wine glass. Pear, apricot, European plum, and sweet cherry are trained and pruned as a modified central leader, which is similar to a central leader tree, but the top of the leader of the tree is pruned back to encourage regrowth.

Mature neglected trees that need renovating are not just a one year project but will take several years to correct. Half the wood of a peach, nectarine, or Japanese plum can be removed in one year. One third of the wood per year for apple, cherry, apricot, and European plum. Remove only one-tenth of the wood per year of pear to reduce vigorous regrowth which is susceptible to a bacterial disease called fire blight.

For further information on pruning, contact the Cooperative Extension office.

Author: 
Rob Call
Issue: 
February, 1998