Spring Pruning

I think I have a pruning fixation. I take most opportunities that come along to write about pruning. I have not blogged yet about Spring pruning. It can be a useful way to achieve some pruning objectives. Like all practices it is not necessarily the method or timing of method of choice for all plants. Spring Pruning can have some specific impacts on development of deciduous fruit trees that may help in the home orchard.

Springtime may not be the most obvious time to prune–in fact springtime within the geographic context of this blog requires definition. For this discussion, springtime is the period during which buds are opening, shoots are elongating, flowers are pollinated, and fruit is set or is rapidly enlarging. These are changes in the tree phenology that are critical to fruit production. As you may recall from previous blogs on pruning there are some basic impacts that pruning has. Pruning is growth limiting. Pruned parts will grow less than unpruned parts. Spring pruning is an opportunity to regulate fruit retention.

Phenology is the growth stage of a tree and defines the period when Spring pruning can begin

Spring growth and tree phenology are not timed to be the same. Apricots will flower before or after peaches, plums, pears or apples. This can happen in different months depending on latitude of your garden. Spring is in set time back to another vegetative shootand Spring pruning is thus variable across location and species in your garden.

So why is pruning in Spring at all helpful? The main reason is to reduce the number of fruit that are set on a tree. Reducing fruit count will allow more sugar to enter fewer fruit increasing the size of remaining fruit and improving quality.
Pruning during bloom is risky, we don’t know what the fruit set will be until a few weeks later. Also changes in weather such as spring frosts, wind, or even hail and snow can destroy a crop in its juvenile stages and if you have already pruned, you have lessened your changes for fruit later. It’s best to wait until fruit have set, are growing, enlarging and that you are pretty sure the crop is under normal progression.

With a Spring prune I like to remove about half the set fruit. This would involve trimming the ends of branches (that have fruit) by 50 percent. You may still need to thin fruit later because the remaining fruitful stems you leave on the tree may have too many fruit to ensure quality. Thinning peaches to about one every six inches in late Spring, reducing pear and apple clusters to one fruit per spur and minor thinning of plums will suffice. Apricots usually need little thinning for adequate quality.

Another reason to thin in Spring is to reduce disease incidence. Peach leaf curl is usually well developed even as fruit is setting. The best control of peach leaf curl is with a dormant fruit tree spray prior to bud break. But, if you miss that opportunity to spray, pruning out the infected leaves and shoots will decrease the inoculum for next year. Dispose of the infested shoots in the trash (although correct hot-composting will likely kill the inoculum as well).

Peach leaf curl can be pruned out in the springtime if you miss your dormant spray

Spring pruning is not recommended in areas where there are frequent rains, bacterial diseases such as bacterial canker or when your trees are not vigorous and otherwise healthy. Pruning creates wounds that allow pathogens to enter the tree and a wise gardener will avoid pruning during warm showery weather. If conditions are dry and sunny, Spring pruning can be effectively used to slow growth and increase fruit quality for the coming summer harvest.

For more information on the science – and myths – behind pruning, Dr. Chalker-Scott and I published a peer-reviewed article on this recently.

Published by

Jim Downer

Dr. Downer has 34 years of experience as a horticulture and plant pathology Advisor with the University of California Cooperative Extension in Ventura County. Dr. Downer’s academic training is from California Polytechnic Univ., Pomona, (BSc. horticulture & botany, 1981; MSc. Biology, 1983;. In 1998 he earned a Ph.D. in plant pathology, from University of California, Riverside. Dr. Downer’s research is focused on mulch, soil microbiology and disease suppression in mulched soils, diseases of shade trees and cultural practices to maintain landscape plants. Dr. Downer is a member of the American Society of Horticultural Science, the American Phytopathological Society, The International Soc. of Arboriculture, and the Western Chapter of the ISA, and the International Society for Horticultural Science. Dr. Downer is an Adjunct professor at California Polytechnic University in Pomona. Dr. Downer serves on the Board of the John Britton Fund for tree Research as the chair of the research advisory committee, and currently chairs the regional conference committee for WCISA. Dr. Downer has a love of shade trees, Shinrin roku (forest bathing/walking) tree work, wood working, horses, gardening, horticulture and the study of plants and their biology.

3 thoughts on “Spring Pruning”

  1. I too have a bit of a pruning fixation, but with all that I have read and the various workshops taken this is my first information in pruning at, or after, blossom. I will be rereading several times to make sure I have it well understood.

    It is starting to seem like we could actually prune apples at just about any time as long as we clearly understand the way the tree will respond under different seasonal conditions.

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