“Dwarf Washington Navel” orange trees may be grown in containers in colder areas.
Gardeners who have a small landscape may still enjoy the benefit of fresh citrus by planting a Dwarf Washington navel orange tree (Citrus sinensis “Dwarf Washington Navel”). These Brazilian natives reach a mature height of only 8 feet and produce sweet oranges that are suitable for fresh eating or juicing. Hardy in U.S. Department of Agriculture plant hardiness zones 9 through 11, “Dwarf Washington Navel” trees grow best in full sunlight and deep, fast-draining, sandy soils.
Water the dwarf Washington navel orange tree when the top 2 to 4 inches of soil becomes dry. Apply water from a garden hose directly to the ground in a ring twice as wide as the tree’s canopy. Keep the water 6 inches from the trunk to avoid causing rot. Do not allow the soil to become soggy.
Clear any weeds and debris from underneath the tree’s canopy. Spread a 2-to-3-inch layer of mulch over the cleared area with a rake. Do not spread the mulch within 6 inches of the trunk. Adding mulch will decrease moisture loss from the soil while inhibiting weed growth.
Fertilize 1- to 3-year-old orange trees with 2 tablespoons of ammonium sulfate 21-0-0 granular fertilizer. Make the first application in the spring just as the tree begins to produce new leaves. Broadcast the fertilizer granules evenly in a ring around the tree, just under the outer edges of the canopy. Mix the fertilizer into the top 3 inches of soil with a rake. Water the area thoroughly. Repeat this application every 3 months during the growing season, up to a total of 3 to 4 times.
Apply 2 pounds of ammonium sulfate 21-0-0 to trees 4 years old and older in the spring once the tree begins to leaf out. Spread the fertilizer in a 12- to 24-inch-wide ring, starting just underneath the canopy edges and extending outward. Mix the fertilizer into the top 3 inches of soil and water the area thoroughly. Repeat this process two additional times per year, spacing each application 3 months apart.
Spread 1 pound of phosphate fertilizer in a ring below the canopy’s edge every 3 to 4 years. Rake the fertilizer into the top 1 inch of soil. Water the area deeply with garden hose..
Spray the newly developing foliage in the spring with an iron, zinc, manganese foliar fertilizer spray. Read all label warnings and instructions before using the product. Apply the spray when the leaves reach two-thirds of their mature size. Spray the leaves until the liquid begins to drip off, completely coating both sides. Apply the spray only in the morning hours on a clear day with no chance of rain.
Whitewash the tree’s trunk every spring to protect the bark from sun damage. Pour 1 part white latex paint with 1 part water into a bucket. Stir the solution with a stick to combine the materials. Paint the whitewash solution onto the bark with a paintbrush. Allow the first coat to dry completely then add a second coat.
Spray the foliage periodically with a steady stream of water to wash off insect-attracting dust and grime. Wash the foliage in the morning hours to provide sufficient time for it to dry before nightfall.
Remove dead, broken and diseased branches throughout the year as they occur. Cut the branch one-quarter inch above an outward facing lateral limb, growth node or branch bark collar with a pair of loppers or a pruning saw. Remove any weak or overlapping branches. Cut out any branch that rubs against another limb.
Set snail and slug traps around the base of the tree to stop these pest from damaging the bark or leaves. Spray foliage infested with mites, whiteflies, scales or aphids with an insecticidal soap or horticultural oil.
Things You Will Need
- Garden hose
- Amonium sulfate 21-0-0 granular fertilizer
- Phosphate fertilizer
- Iron, zinc, manganese foliar fertilizer spray
- White latex paint
- Loppers or pruning saw
- Snail or slug traps
- Insecticidal soap or horticultural oil
- Monrovia: Dwarf Washington Navel Orange
- University of California: Citrus for the Home Garden in Contra Costa County
- University of California: Questions and Answers to Citrus Management
- Sunset Western Garden Book; Kathleen Norris Brenzel, ed.
- Rodale’s All-New Encyclopedia of Organic Gardening: The Indispensable Resource for Every Gardener; Fern Marshall Bradley, et al.
- Jupiterimages/Photos.com/Getty Images