Orange and blood orange

Citrus x sinensis · Citrus family (Rutaceae)

At a glance
Hardiness zones	9 to 11
Sun	full sun
Water	moderate
Life cycle	perennial
Frost	Tender: killed by frost
Soil pH	5.5–6.5
Spacing	144 to 288 inches

About Orange and blood orange

Sweet oranges are evergreen trees with fragrant white spring flowers and juicy fruit; home types include navels, juice oranges like Valencia and Hamlin, and blood oranges such as Moro, Tarocco and Sanguinelli. Blood oranges get their red flesh from anthocyanin, the pigment in purple grapes, and it colors best where winter nights turn chilly. A smaller tree on a dwarfing rootstock makes a good porch tree in colder areas.

NC State lists sweet orange for zones 9a-11b; trees are badly damaged in the low to mid 20s F, so north of zone 9 grow them in pots and bring them in (UGA; Mississippi State).

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Set out plants: up to 2 weeks after the last frost

A potted tree goes outside after the last spring frost and is eased into full sun over about two weeks (Maryland Extension; Wisconsin says wait until temperatures stay above 50 F). In the ground (zones 9-11), UGA advises planting in early spring after freezes are past. Budded trees may bear a few fruit in the second year but usually start in the third (Texas A&M).

Soil

Well-drained soil; UF recommends a pH of about 5.5-6.5 for home citrus, and in pots a fast-draining bark-based mix (UF/IFAS; Mississippi State).

Pot it in a fast-draining, slightly acid potting mix (bark-based, or palm-and-cactus mix) in a container with drainage holes, never garden soil; in the ground, test the soil and keep the pH around 6.0-7.0 (Mississippi State; UC Master Gardeners; UGA).

Feeding

First feeding after planting, once new growth starts (about 4 to 6 weeks): citrus fertilizer with micronutrients (about a 2-1-1 or 3-1-1 N-P-K ratio with iron, manganese and zinc, or a slow-release 12-6-6 or 12-4-6). Follow the label for a pot; in the ground, UGA starts a young tree with about 1/3 lb of 8-8-8 with micronutrients spread in a 30-inch circle and watered in.
Early spring each year, as new growth begins: citrus fertilizer with micronutrients (N-P-K about 2-1-1 or 3-1-1). Slow-release granules need 2 to 3 feedings a season; a water-soluble citrus food can instead go on about once a month from late winter to fall (Clemson; Maryland; UC Master Gardeners; Texas A&M).
Early summer: citrus fertilizer with micronutrients. Repeat the spring feeding at the label rate and water it in (Maryland Extension).
Late summer (the last feeding of the year): citrus fertilizer with micronutrients. Give the final feeding, then stop by early fall so new growth can harden before winter; in the ground, UGA says no fertilizer from August 1 to February 15.
Any time young leaves turn yellow with green veins: chelated iron fertilizer or a sulfur soil acidifier. Apply as the label directs; this pattern usually means iron is short or the mix is not acid enough (Maryland Extension).

Don't feed through the winter indoors (Wisconsin and Minnesota feed only about April to September), and don't overwater or let the root ball dry out: too much water drops leaves and too little drops flowers (Maryland; Mississippi State).

Harvest

Pick by taste, not color: sweetness does not go up after picking, and ripe Valencias can turn greenish again on the tree (UC IPM). At Riverside, navels ripen about November to January, blood oranges December to February, and Valencias in spring and summer, and the fruit keeps best left on the tree (UC Riverside; UC IPM).

Oranges give one crop a year whose timing depends on type: navels may not be ready until late winter and Valencias ripen in summer. Ripe fruit keeps best on the tree, so pick as you need it; picked fruit keeps 4-6 weeks in the refrigerator.

Varieties (15)

Variety	Type	Notes
Moro	Blood orange	Pleasant, with a distinctive aroma; flavor fades if the fruit is stored too long. The darkest blood orange: flesh deep violet-red, rind orange with a light red blush. Medium to medium-large fruit, few or no seeds. Medium-size, spreading, very productive tree.
Ruby	Blood orange	Rich. Medium fruit with relatively few seeds; orange flesh streaked with red in good years, but coloring is unreliable. Compact, moderately vigorous, productive tree.
Sanguinelli	Blood orange	Can still be tart early in the season. Striking deep red rind color and red flesh. Fruit can run small when the crop is heavy. Small to medium, thornless, very productive tree.
Tarocco	Blood orange	Very good; UC Riverside calls it one of the most delicious blood oranges in its collection. Medium-large to large fruit with few or no seeds; red flesh but little or no red on the rind. Vigorous tree with moderate yields.
Hamlin	Early juice orange	Sweet and low in acid. Medium-small, smooth-skinned fruit with six or fewer seeds. Productive tree, more cold tolerant than most sweet oranges.
Valencia	Juice orange	Smooth, thin-skinned fruit; seed count varies. Ripe fruit can turn greenish again on the tree without losing quality.
Pineapple	Midseason juice orange	Rich and sweet with a delicate fragrance. Medium, moderately seedy fruit. Thornless, very productive tree, but more easily hurt by frost than most oranges.
Fukumoto	Navel orange	Deep reddish-orange rind; medium to large, mostly seedless fruit. Tree tends to be smaller than other navels.
Lane Late	Navel orange	Sweet, getting better balanced later in the season. Similar to Washington navel in size, with a smoother peel and a smaller navel; usually seedless.
Robertson	Navel orange	Slightly lower quality than Washington navel. Medium-large seedless fruit that often grows in tight clusters. Small, less vigorous but very productive tree.
Washington navel	Navel orange	Rich, with firm, deep-colored flesh. Large, seedless, easy-peeling fruit with a slightly pebbled rind. Tree is not very vigorous, with a rounded, somewhat drooping canopy.
Cara Cara	Navel orange (pink-fleshed)	Pink flesh colored by lycopene; small navel and a plain orange rind. Tree much like Washington navel.
Shamouti (Jaffa)	Sweet orange	Pleasantly sweet. Medium-large, oval, nearly seedless fruit with a thick, tough peel that comes off easily. Upright, thornless tree.
Trovita	Sweet orange	Mild, pleasant and juicy. Medium-small, few-seeded fruit without a navel. Vigorous, upright tree that may bear heavily every other year.
Midknight	Valencia-type juice orange	High juice and sugar content. Large, nearly seedless fruit with a smooth rind. Tree grows more slowly than standard Valencia and has large leaves.

Pests to watch for

Asian citrus psyllid, Citrus leafminer, Scale insects, Mealybugs, Aphids, Whiteflies, Twospotted spider mite, Thrips, Brown garden snail, Katydids, Ground squirrels, Roof rats and Norway rats

Diseases and problems

Citrus greening (HLB), Citrus canker, Phytophthora root rot, Foot rot (gummosis), Greasy spot, Citrus scab, Sooty mold

In the kitchen

Eaten fresh or juiced: navels are seedless and peel easily, Valencia is the classic late juice orange, and blood oranges give deep red flesh and juice (UC Riverside; UF/IFAS).

Keeping it: Refrigerate oranges in a plastic bag for a few weeks; on the counter they keep only days. Squeezed juice is best within a day.

Safety: The fruit is a common food. FDA warns that sour (Seville) oranges and tangelos may interfere with some medicines the way grapefruit does, and that the allergy drug fexofenadine may work less well with orange juice. NC State notes the plant's oils can cause contact dermatitis.

Pets: Toxic to dogs, cats and horses (ASPCA): the fruit is edible, but peel, leaves and stems contain essential oils and psoralens that can cause vomiting, diarrhea, depression and skin irritation.

Sources

Photo: Photo: Dvortygirl, CC BY-SA 4.0, via Wikimedia Commons (CC BY-SA 4.0). Photo resized for the web.

Planting dates and advice are general guidance; check with your local Cooperative Extension office for your area.