Pronounciation: CI-trus re-ti-cue-LA-ta

Hardiness zones:
Sunset 12-24
USDA 9-11

Landscape Use: Accent, edible gardens, residential fruit tree, mesic and oasis landscape design themes, attracts bees.

Form & Character: Upright, rounded, symmetrical, domestic, colorful, abundant.

Growth Habit: Evergreen, woody perennial large shrub to small tree, moderate growth rate to 10- to 20-feet tall with similar spread.

Foliage/Texture: Medium green, glaborous and leathery leaves are oblong, elliptical, or oval, tapering to a blunt tip, 2-inches long, 1.5-inches wide, petiole wings are slim, lamina midvein is prominent, sometimes stems bear extended thorns; medium texture.

Flowers & Fruits: Flowers are borne in small clusters in leaf axils, flower buds are purplish, but open flowers have five distinct white petals, up to 2-inches across, highly fragrant. Flowers are hermaphroditic (has both male and female organs), self fertile, pollinated by bees; fruits are a hesperidium berry, globose to oblong, 1- to 3-inches long, fruit apex rarely nippled, exocarp ripens to orange, yellow-orange, or red-orange with smooth to bumpy rinds dotted with oil glands, aromatic, exocarp + mesocarp (rind) easily separates from the endocarp (easy to peel a mandarin), endocarp haves 8-10 segments (carpels), segments contain seeds 0 to many seeds.

Fruit lover's tidbit: Type 1, genetically pure 'wild' mandarin oranges are bitter in taste. The sweetness of Type 3, late mix mandarins that we are all familiar with today is derived from hybridization with Citrus maxima (pomelo).

Seasonal Color: Orange, yellow-orange, or red-orange fruits typically ripen in late fall and winter.

Temperature: Cold hardy to 26^oF and heat intolerant above 118^oF. Like all citrus in Phoenix, significant heat stress injury (leaf yellowing and necrosis) occurs above 112^oF, especially if located in full western sun.

Light: Full sun to filtered shade or some shade from western summer sun, no full shade.

Soil: Tolerant, but well drained soils is essential. Maintaining adequate to optimal soil fertility levels crucial for successful culture of mandarin. Generally, mandarin like other citrus will need to be fertilized with a balanced, complete fertilizer containing micronutrient supplements (Fe, Zn, and Mn) three times each year (January, May and September).

Watering: Moderate and consistent patterns of supplemental irrigation are neccesary for successful desert culture, but irrigation frequency and duration varies with time of year and soil texture. In general, flooded, berm irrigations are superior to drip irrigation (less accumulation of soil salts in the rhizosphere).

Pruning: Only infrequent, 'light' pruning is required. Pruning strategies should always NOT incude crown raising because all Citrus taxa are HIGHLY prone to trunk scald if exposed to direct summer sunlight.

Here's a sustainable tip: If the 'Horticultural clods of Phoenix' (aka 'Hort clods') have wandered (like migrant nomads) into your yard and 'lolly popped' your mandarin orange trees by raising the crown base to expose their trunks to direct sunlight, then promptly respond by painting the trunk surfaces with a mixture of white flat latex paint and water (1:1 ratio) to protect the exposed trunks from summer sunscald injury.

Propagation: Softwood or semi-hardwood stem cuttings, grafting, budding.

Disease and Pests: All citrus are prone to numerous, well-documented, mostly soil-derived, biotic and abiotic pressures. Citrus greening disease is especially lethal and has resulted in the USDA barring interstate transport of live citrus trees.

Additional comments: Mandarin orange is an excellent large shrub to small tree for Phoenix residential backyard landscapes. Best used in oasis and mesica landscape design settings.

There are several wonderful mandarin orange cultivars that perform well in the lower Arizona desert.

These include:

• 'Daisey' - medium- to large-size fruit, early-season mandarin with a reddish orange exocarp, endocarp very sweet, few seeds (typically 0 to 5)
  
• 'Clementine' (Algerian)- smaller tree size, hybrid of sweet orange and mandarin, small fruits, aromatic, mesocarp separates easily from endocarp (easy to peel), sometimes seedless, best for fresh consumption
  
• 'Fairchild' - hybrid of 'Clementine' mandarin and 'Orlando' tangelo. vigorous widespreadin tree, medium-sized, oblate shaped fruits, thin, slightly pebbled, dark orange exocarp, rind (exocarp + mesocarp easily separates from endocarp (eay to peel), segments contain many seed, high juice content, richly sweet
  
• 'Freemont' - medium-sized, bright orange oblate fruit with smooth thin rind (exocarp + mesocarp), easily separates from endocarp (easy to peel), endocarp with high juice content, sweet, slightly acidic flavor, useful for fresh consumption or in recipes, heavy bearer
  
• 'Golden Nugget' - juicy fruit with a deep orange, very bumpy and ribbed exocarp (rind) with high oil content, easy to peel, strongly aromatic, endocarp has a sweet, rich, full flavor
  
• 'Kinnow' - late season, medium-sized, round- to oblong-shaped fruit with a flattened top and bottom rind (exocarp + mesocarp) is thin and smooth with many sunken oil glands, highly aromatic, very sweet endocarp, many seeds
  
• 'Shiranui' - hybrid cross between the 'Kiyami' tangor and the 'Ponkan' tangerine, oblong large size fruits with a roughened, nippled, thick rind (exocarp + mesocarp), endocarp very sweet, high juice content, seedless
  
• 'Tango' - medium-sized fruits with a squat shape and a smooth, easy-to-peel rind, and juicy, seedless endocarp (flesh) with a sweet-tart flavor, used for culinary recipes and drinks
  

Taxonomic extras: Calamondin or calamansi (Citrus x microcarpa) is hybrid cross of mandarin orange and kumquat (Fortunella sp.). Its peel is sweet, while the endocarp (flesh) is sour and tangy with notes of mandarin. Used in cooking recipes for marmalade, cupcakes or pies. The mandarinquat cultivar 'Indio' is a fascinating open-pollinated seedling cross of mandarin and the 'Nagami' kumquat (Citrus japonica).