Fertilizing Established Plants….A Weird Science

 

Feeding Established Trees in Open Areas:

Apply recommended amount of fertilizer, based on the size of the tree, to the soil that is directly below the perimeter of the tree’s canopy. If practical, work fertilizer into soil. Then apply recommended amount of water. 
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Feeding Established Trees in Tree Wells:

Minimum recommended tree well size is 6 feet diameter. If your tree wells are smaller than 6 feet in diameter, please ask for assistance in deciding how much fertilizer to apply. Always reduce the amount of fertilizer applied to trees in wells, but increase the frequency of feedings to one time per month in spring and fall only.

Apply no more than 5 cups of fertilizer to the soil that is at the perimeter of the tree well. If practical, work fertilizer into soil. Then apply recommended amount of water. 
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Non-Desert Trees:

Dispersul (Soil Conditioner):

When:

First half of February, first half of May, & second half of August.

Rate:

Trees less than 15’ tall = 15 cups per tree per treatment.
Trees 15’ – 20’ tall = 15 – 20 cups per tree per treatment.
Trees 20’ – 25’ tall = 20 – 30 cups per tree per treatment.
Trees taller than 25’ = 30 – 40 cups per tree per treatment.

Apply a slow and thorough deep watering to area of treatment immediately after application.

Treeland Nurseries General Purpose Fertilizer 16-8-2:

When:

Second half of February, Second half of May, & mid-September.

Rate:

Trees less than 15’ tall = 2 to 3 cups per tree per treatment.
Trees 15’ – 20’ tall = 4 – 6 cups per tree per treatment.
Trees 20’ – 25’ tall = 8 – 10 cups per tree per treatment.
Trees taller than 25’ = 12 cups per tree per treatment.

Apply a slow & thorough deep watering to area of treatment immediately after application to prevent burning. 
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Non-Desert Shrubs:

Dispersul (Soil Conditioner):

When:

First half of February, first half of May, & second half of August.

Rate:

Shrubs less than 2’ tall = ½ cup per shrub per treatment.
Shrubs 2’ – 3’ tall = 1 to 2 cups per shrub per treatment.
Shrubs 3’ – 5’ tall = 2 to 3 cups per shrub per treatment.
Shrubs taller than 5’ = 3 to 5 cups per shrub per treatment.

Apply a slow and thorough deep watering to area of treatment immediately after application

Treeland Nurseries General Purpose Fertilizer 16-8-2:

When:

Second half of February, Second half of May, & mid-September.

Rate:

Shrubs less than 2’ tall = ¼ to 1/3 cup per shrub per treatment.
Shrubs 2’ – 3’ tall = 1/3 to 1/2 cup per shrub per treatment.
Shrubs 3’ – 5’ tall = 1/2 to 1 cup per shrub per treatment.
Shrubs taller than 5’ = 1 to 2 cups per shrub per treatment.

Apply a slow & thorough deep watering to area of treatment immediately after application to prevent burning. 
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Desert Trees & Shrubs:

Follow the General Purpose Fertilizer instructions for either trees or shrubs, but the Dispersul soil conditioning in not necessary for plants that tolerate high soil pH levels.

MIRACLE-GRO OR EQUIVALENT: Not with General Purpose Fertilizer

Rate:

Apply bi-weekly between mid-February through late May.
Apply bi-weekly between late August through late October

TRACE ELEMENTS (MICRONUTRIENTS):

Treeland Nurseries General Purpose Fertilizer contains sufficient amounts of trace elements for most plants, except as noted with queen palms and their use of Manganese. Other non-desert plants may require larger quantities of

iron, zinc, and magnesium than are supplied in fertilizer. These elements can be purchased separately and be applied with general purpose fertilizer or applied alone.

Apply a slow & thorough deep watering to area of treatment immediately after application to prevent burning. 
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Citrus:

Gypsum (Soil Conditioner):

When:

First half of February, first half of May, & second half of August.

Rate:

Trees less than 6’ tall = 5 – 8 cups per tree per treatment.
Trees 6’ – 10’ tall = 8 – 12 cups per tree per treatment.
Trees 10’ – 15’ tall = 12 – 16 cups per tree per treatment.
Trees taller than 15’ = 20 cups per tree per treatment.

Apply a slow and thorough deep watering to area of treatment immediately after application.

Treeland Nurseries General Purpose Fertilizer 16-8-2:

When:

Second half of February, Second half of May, & mid-September.

Rate:

Trees less than 6’ tall = ½ to 3 cups per tree per treatment.
Trees 6’ – 10’ tall = 4 – 6 cups per tree per treatment.
Trees 10’ – 15’ tall = 6 – 8 cups per tree per treatment.
Trees taller than 15’ = 12 cups per tree per treatment.

Apply a slow & thorough deep watering to area of treatment immediately after application to prevent burning. 
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Queen Palms:

Dispersul (Soil Conditioner):

When:

First half of February, first half of May, & second half of August.

Rate:

Trees less than 6’ tall = 5 – 8 cups per tree per treatment.
Trees 6’ – 10’ tall = 8 – 12 cups per tree per treatment.
Trees 10’ – 15’ tall = 12 – 16 cups per tree per treatment.
Trees taller than 15’ = 20 cups per tree per treatment.

Apply a slow and thorough deep watering to area of treatment immediately after application.

Treeland Nurseries General Purpose Fertilizer 16-8-2:

When:

Second half of February, second half of May, & mid-September.

Rate:

Trees less than 6’ tall = ½ to 2 cups per tree per treatment.
Trees 6’ – 10’ tall = 2 – 4 cups per tree per treatment.
Trees 10’ – 15’ tall = 4 – 6 cups per tree per treatment.
Trees taller than 15’ = 10 cups per tree per treatment.

Manganese Spikes or Manganese-Sulfate 31%: Apply with General Purpose Fertilizer.

When:

Second half of February & mid-September.

Rate:

Trees less than 6’ tall = 2 spikes per tree per treatment.
Trees 6’ – 10’ tall = 4 spikes per tree per treatment.
Trees 10’ – 15’ tall = 6 – 8 spikes per tree per treatment.
Trees taller than 15’ = 8 – 10 spikes per tree per treatment.

Apply a slow & thorough deep watering to area of treatment immediately after application to prevent burning. 
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Lawns:

Turf Royal 21-7-14

Rate:

3 – 5 lbs. Turf Royal per 1000 square feet of lawn every 4 – 8 weeks.

Apply a slow and thorough deep watering to area of treatment immediately after application

Dispersul (Soil Conditioner):

When: First half of February, first half of May, & second half of August.

Rate:

20 lbs. per 1000 square feet of lawn.

Apply a slow & thorough deep watering to area of treatment immediately after application to prevent burning. (Return to top)

Fertilizer Elements:

Element/Form Action in Plant Deficiency Symptom
NITROGEN Gives dark green color, induces rapid growth, increases protein content, and gives crisp leaf quality Yellowing, then dropping of older leaves, small leaves or stunted growth.
PHOSPHORUS Promotes root development, flowering, seed formation, and hastens maturity. Purple edges to leaves, delays fruit maturity, die back on leaf tips, and early defoliation.
POTASSIUM Increases vigor, disease resistance, cell turgidity, and ability to take-up water. Mottling or curling, green mid-rib, and yellowing at the tips or margins of older leaves. Plant lodges easily.
SULFUR Correct for high soil pH. Essential in plants for protein formation, root growth, and seed production. Young leaves general yellowing but not along the mid-rib. Stalks short and slender.
IRON Essential to chlorophyll production, enzyme formation and protein synthesis. Chlorosis in young leaves, most veins remaining green.
MAGNESIUM A component of chlorophyll and aids in the translocation of phosphorus. Older leaves light green, mottled with dead spots.
ZINC Used for enzyme production, protein synthesis, and seed and growth hormone formation. Mottled leaves with interveinial chlorosis, and white appearance to buds.
MANGANESE Used by plants for photosynthesis, respiration, and certain nitrogen transformations. Yellowing of leaves, small veins green, and dead spots scattered over entire leaf.
BORON Used by plants to control the rate of water absorption, cell division, and sugar translocation. Rosetting effect or death of the terminal

bud, fruits, flowers, and root tips.

COPPER Used by plants for respiration, photsynthesis, nitrogen fixation, and the utilization of iron. Permanent wilting of young leaves and weak stalks.
MOLYBDENUM Used by plants for nitrogen fixation and the activation of enzymes. Interveinial chlorosis in leaves and plant becomes stunted.
CALCIUM Promotes early root formation and growth. Also improves plant vigor. Death of terminal bud and leaves have wrinkled appearance along margins.

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Information courtesy of Treeland
Nursery

For more informative answers to questions contact the University of Arizona, Maricopa County, Cooperative Extension Service at (602) 470-8086.