Fertilizing Fruit Trees and Blueberry Bushes
Written by Patricia Lunn Adsit, Guilford County Extension Master Gardener
How does a nice piece of apple pie sound? Or, would you rather a slice of blueberry? Maybe a dollop of home-grown fruit jam on that hot biscuit? Is your mouth watering yet?
There is a saying (borrowed from the late Stephen Covey) I use frequently “in my real life:”*
‘Begin with the end in mind.’
If you start out thinking about all the lovely taste-treats your fruit trees and berry bushes can yield, you are more likely to give them the care and attention they need in the early days of the growing season. And that’s exactly where we are! Late Winter, while the other parts of your gardens lie dormant and require little of your attention, is the perfect time to pour some energy into your future fruit crop.
Step One will always say “Perform a soil test.” Not sure about this requirement? Read up on the basics in NC here: http://guilford.ces.ncsu.edu/2013/01/knowledge-is-power-test-your-soil-soon/. Remember, applying fertilizer without knowing whether it is needed can result in poor fruit quality and excessive plant growth. Excessive fertilization also wastes your money and contributes to environmental pollution. Additionally, excessive green growth can promote some pest problems.
Here are some guidelines:
* Fruit trees (such as apple, pear, peach, cherry, plum, crabapple, etc.; not including citrus):
Let the tree’s age (the number of years since the tree was planted in your home orchard) and previous year’s growth be your roadmap to success.
If you added fertilizer when planting a new (1-2 year old) tree, you can usually withhold additional fertilizing for a couple more years, or until your tree starts bearing fruit, as long as there is adequate tree-growth each year. (Nonbearing fruit trees should grow approximately 15 to 30 inches per year; bearing trees 8 to 15 inches, depending on variety.) At this point in the young tree’s life, providing and maintaining adequate moisture, in the form of watering and mulching, and good weed control are the most important things to consider. Additionally, fruit tree roots will absorb nutrients, especially if there is lawn in the vicinity that is fertilized on a regular basis.
Information from NC State University suggests “Trees with less than 10 to 12 inches of (previous) season’s growth on lateral branches may need fertilizer. On the other hand, trees with greater than 18 inches of growth may not need fertilizer for several years.” Fertilization should occur immediately before bloom or leaf sprout occurs, which is usually in late-February to mid-March in the Piedmont of NC.
Apply an amount recommended by your soil test report, or up to 1 pound of a balanced fertilizer such as 10-10-10 per tree for each year of the tree’s age (if known) or per inch of trunk diameter. Caution: one pound of actual nitrogen (or 10 pounds of 10-10-10) is the maximum for fruit trees 10 years of age and older. Always bear in mind that too much fertilizer promotes excessive vegetative growth, and may actually deter fruit production.
To apply, uniformly broadcast the recommended amount of fertilizer in a circular band from about 1-2 feet from the trunk and extend out slightly beyond the drip-line of the tree. Rake the fertilizer into the top couple of inches of soil. Water and mulch well.
Preferably, fertilizers should be applied to established blueberries in late Winter or early Spring** before foliage is present and should be spread evenly, to avoid root injury, and away from the stem. Care should be taken to apply the fertilizer only when the foliage (if present) is dry, so that fertilizer particles do not damage the foliage. Apply the recommended amount from your soil test report, with 4 inches of rain or an equivalent amount of irrigation between applications. Apply fertilizer to the individual blueberry bushes, on young plants. On older plantings, the fertilizer may be applied either by hand to the individual plants or broadcast with an applicator. Caution: Blueberries are easily damaged by excess fertilizer.
First Year – Do not fertilize immediately after planting. Wait about a month after planting, or until the first leaves have reached full size, then apply 1 T of acid-loving plant fertilizer (like that for azaleas) or 10-10-10 within a circle 12 inches from the bush, always taking care to keep fertilizer away from the stem of the plant. Repeat application of fertilizer at 6-week intervals, depending upon rainfall or irrigation until about August 1 in the Piedmont. As nitrogen is the element to which blueberries are most responsive, use 1/2 T of 21-0-0 instead of the complete fertilizer for the second and subsequent applications, particularly if phosphorus was above 60 on your soil test.
Second Year – Double the first year’s rates and increase the circle around plants to 18 inches. Apply the first application when new growth begins in Spring.
Bearing Plants – When growth begins in Spring, apply 1 cup of complete fertilizer such as 10-10-10 within a circle 36 inches from the bush. If more vigorous growth is desired, sidedress with 1/4 cup of 21-0-0 at 6 week intervals. [Determine the sidedressing requirement based on the amount of shoot growth: on mature bushes, 6 to 12 inches of new growth is adequate for optimal balance of plant size and yield.] Prune away any additional growth. While this may result in a loss in fruit, it is necessary to keep the blueberry bushes from becoming excessively large.
**A special note: Rabbiteye blueberries, a variety proven successful in the Piedmont, are sensitive to overfertilization and to certain types of fertilizers (nitrogen in nitrate form). Split-application (2-3 times per year) of fertilizer is preferable to a single, high dosage feeding in March. Slow-release synthetic fertilizer and organic forms are beneficial for this reason.
Having trouble with measuring the correct amount? Remember the old adage: “A pint’s a pound the whole world ‘round.” (A pint of fertilizer weighs about 1 pound.)
With proper care for your fruit trees and berry bushes in the early stages of annual growth, those taste-tempting pies and preserves are just a few months away!
Read more about it:
Fertilizing Fruit Trees:
*In her “real life,” Guilford County EMGV Patricia is a career development coach and writer, living in High Point, NC. But she truly enjoys time spent with her husband, tending their 1/4 acre Way Back Gardens…including their 18 dwarf fruit trees and 9 blueberry bushes.