How to Prune Plum Trees in California

Plum trees thrive in California's fertile soil and temperate climate.

Plum trees flourish in California's climate and soils. While these trees provide California orchardists with masses of fresh fruit, they also double as an attractive ornamental tree in landscapes and parks. Plum trees don't seem to mind this Pacific state's wet winter soils or the intense summer heat. Pruning your plum tree at the correct time will help ensure an abundant yield of fruit and enhance the health of the tree.

Things You'll Need

• Pruning shears
• Dormant oil

Instructions

1. Perform the initial pruning at the time of planting. In California, the average planting time occurs early in the spring, before the heavy rains. Freezing temperatures in areas like Lodgepole and Tahoe Valley often necessitate planting after the final frost of the season. During planting, prune off any broken, diseased or lopsided growth from the plum trees. Use pruning shears to cleanly remove the branches slightly above the damaged growth.

2. Prune your trees lightly in the early winter. While plum trees thrive under California's bright, summer sun, the cloudy winter and spring months can leave them without adequate sunlight. Remove about 20 percent of the previous season's growth to let in more light. Wait until the trees lose their leaves and enter their dormant period. Thin the canopies by selecting the most crowded branches for pruning. After pruning in the winter, spray the plum trees with dormant oil to help protect them from San Jose scale, mite eggs and aphid eggs.

3. Train your plum trees by performing the annual pruning session in the late spring or early summer. Pruning during this time in California will help produce the desired growth and shorten the length of time for fruiting. Begin pruning early in the day, before the temperatures hit 60 degrees Fahrenheit. This may mean pruning early in the morning in warm areas of Southern California. Early morning pruning will help protect the plum trees from the midday heat.

4. Train plum trees by pruning away the vertical branches that grow straight up. These branches do not form load-bearing branches that support quality fruit production. Remove these vertical branches near their point of origin.

5. Encourage fruiting by snipping off the tips of long branches during the annual pruning session. Cutting off the tips of the plum trees also helps to restrict their outward growth, keeping them from sprawling.

Tips & Warnings

• During the annual pruning session, water your plum trees about 24 hours prior to the scheduled pruning. Adequate water at this time can help protect fruit trees from the stress of heavy pruning.

References

• University of California: Training and Pruning Fruit Trees
• The California Backyard Orchard: Plum and Prune
• Climate Charts: California Climate Charts
• "Principles of Horticulture", C.R. Adams, 2008

Resources

• "Silverleaf Disease Management"; Roger Duncan