How to Plant a Washington Navel Orange

When and where to plant

Washington Navel Orange is hardy in zones 9 through 11 and grows best in full sun, eight or more hours of direct light each day. In zones 8 and colder, grow the tree in a large container that can move indoors or into a garage when nights drop below 28°F. Cold protection below 28°F is the boundary that decides whether this tree lives outdoors year-round or travels with the seasons.

Plant in spring once nights stay reliably above 50°F. Late frosts on freshly planted citrus damage new flushes that the tree cannot afford to lose in its first months. The site needs sharply drained soil with a slightly acidic to neutral pH, around 6.0 to 7.0. Heavy clay holds water against the roots and invites foot rot, the most common killer of young citrus, so on poorly drained ground plant on a six-inch mound or in a raised bed.

Space from structures by twelve to fifteen feet so the mature canopy has room to spread and air can move through the branches. For containers, pick a pot with several large drainage holes that holds at least fifteen to twenty gallons of mix.

Planting a container-grown tree

The single most important rule for Washington Navel Orange is the graft union, the knobby bump a few inches above the root ball where the orange wood was joined to a hardier rootstock, must sit two to three inches above the finished soil. Bury the union and the scion grows its own roots, undoing the cold and disease resistance the rootstock provides, and the soggy bark around the union invites foot rot.

1. 1
   Pick a planting day Aim for a mild spring day after nights have stayed above 50°F for at least a week. Hot afternoons pull moisture out of freshly transplanted citrus foliage faster than new roots can replant it. If you must plant on a warm day, do it in the early morning and rig temporary shade through the first afternoon.
2. 2
   Dig the hole twice as wide Measure the root ball, then dig a hole twice as wide and the same depth, never deeper. Citrus roots grow laterally, so a wide hole loosens the ground they need to push into. Digging too deep lets the tree sink as the loose soil settles, which buries the graft union and starts the slow decline this article exists to prevent.
3. 3
   Set the graft union above soil Slide the tree out of the nursery container and find the graft union, the knobby diagonal scar two to six inches above the top of the root ball. Position the tree in the hole so the union will sit two to three inches above the finished soil level after backfilling. On heavy or poorly drained ground, plant on a slight mound to keep water away from the lower trunk as well.
4. 4
   Score the roots if they are circling Look at the sides of the root ball before you set the tree in the hole. If roots are wrapping the container in a spiral, use a clean knife to make three or four shallow vertical cuts down the sides, about half an inch deep. Scoring tells the roots to branch outward into native soil instead of continuing the circle, which they sometimes never break out of on their own.
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   Backfill, water in, and mulch Hold the tree upright as you backfill with the same native soil you removed, firming gently to remove large air pockets. Water the planting hole slowly until the soil settles, then top with two to three inches of mulch, keeping the mulch six inches back from the trunk. Mulch piled against the bark holds moisture against the graft union and invites the foot rot the depth rule is meant to prevent.

The first year

The first year for a newly planted Washington Navel Orange is mostly an underground story. The tree is moving energy into pushing roots out into native soil, building the foundation that supports decades of fruiting later. Above ground, expect modest leaf changes and very little new branch growth.

The most common new-grower mistake is reading slow above-ground growth as a sign of trouble and pushing fertilizer or extra water at the tree. Citrus roots will rot in soggy soil long before the tree shows leaf symptoms, and a heavy nitrogen dose pushes leafy growth the young root system cannot support. Stick to one to two inches of water a week, adjusted for rain, and hold off on regular fertilizer until you see steady new growth in spring.

Healthy first-year growth looks like glossy dark green leaves, one short flush of new shoots in late spring, and possibly a small number of fragrant white blooms that you should pinch off so the tree puts that energy into roots.

What can go wrong

1. Yellowing leaves in the first weeks

   Soggy soil starving the roots of oxygen is the usual cause, especially on clay or in a container without enough drainage. Check that the soil feels dry an inch down before watering again. If water sits in the planting hole for more than a day after rain, lift the tree and replant on a six-inch mound or move to a sharper-drained spot. Withhold fertilizer until new growth returns.

2. Heavy leaf drop after planting

   Transplant shock from the move out of the nursery container is normal, but heavy leaf drop in the first month points to root disturbance or temperature stress. Keep the root zone evenly moist, not wet, and avoid disturbing the tree once it is set. Shade the canopy for the first week if afternoon sun is intense, and protect from any night that drops below 50°F. Most trees push fresh leaves within three to six weeks.

3. Buried graft union (slow decline)

   If the graft union disappeared into the planting hole or under added mulch, the tree is slowly losing the protections the rootstock provides and the bark around the union is vulnerable to rot. Gently excavate the area around the trunk with your hands until you can see the knobby scar clearly, then pull soil and mulch back from that point. Done within the first year, recovery is usually full. Done after several years, the decline is often too far along to reverse.

4. Mushy bark and dark sap at the trunk base

   Foot rot, caused by a Phytophthora fungus in soggy soil, attacks the lower trunk and graft union of young citrus. Pull mulch and soil six inches back from the trunk and let the area dry out. If the bark is already mushy, scrape the dark tissue away with a clean knife to expose dry healthy wood and let it air-cure. Going forward, water based on whether the soil feels dry an inch down rather than on a fixed schedule, and never let mulch touch the trunk.

5. Brown crispy leaves after a cold night

   Temperatures below 28°F damage citrus foliage and the freshly planted tree has not yet built the root depth to recover quickly. In zones 9 and warmer, throw frost cloth over the canopy when the forecast dips into the low 30s, and water the soil deeply the day before since moist ground holds heat. In colder zones, move container trees indoors or into a garage for the night. Wait until late spring to prune any damaged wood so you can see what truly died back.

6. Sunburned bark on the south or west side

   Young citrus bark scalds in strong sun when the canopy has not yet shaded the trunk. Look for cracked or peeling tan patches on the side that faces the afternoon. Paint the lower trunk with a 50/50 mix of white latex paint and water, or wrap it with light-colored tree wrap for the first season or two. The white surface reflects heat and lets the bark cool while the canopy fills in.

7. Blossom and fruitlet drop in year one

   A first-year tree drops most or all of its blooms and small fruitlets because it cannot yet support fruit and root growth at the same time. This is healthy behavior, not a problem. Pinch any blooms you see in the first spring so the tree directs that energy into the root system. Expect a small first crop in year two or three once the canopy and roots have caught up to each other.

8. Tree never settles in after planting

   A root-bound nursery tree planted without scoring the root ball sometimes never breaks the circle, and the canopy stays the same size for years. Lift the tree in the next dormant period, score the sides of the root ball deeply, and replant at the correct graft-union depth. If the roots are dense and matted, soak the ball in water and tease the outer roots loose with your fingers before setting it back in the hole.