Hardiness zones
Sunset 13-24
USDA 9-11
Landscape Use: Residential fruit bearing tree, background, screen for mesic green landscape designs.
Form & Character: Rounded, clean, formal
Growth Habit: Moderate growth rate to 15' to 30' with equal spread age, has a rounded top of spreading branches; the trunk may exceed 6" in diameter; that of a very old tree actually attained a trunk circumference nearly 8'.
Foliage/texture: Foliage is ovate, simple entire, obvious central vein, green with a winged petiole, often with stem thorns ;medium texture
Flowers & fruits: White, axillary 4 petaled flowers, fragrant; fruit a hesperidium, round or oblate to slightly pear-shaped, 4" to 6" wide with smooth, finely dotted peel, usually 3/8" thick, multicarpulate mesoderm either a pale-lemon, sometimes blushed with pink, and aromatic, slightly bitter.
Seasonal color: Flowers in February, fruit ripen the following December.
Temperature: Mature trees are cold hardy to 25oF. Above 110oF leaves will ywllow and trunks will scald if ecpose to direct sunlight.
Light: Full sun
Soil: Grapefruit trees in alkaline desert soils need a regular fertilizer program. Apply a complete and balanced fertilizer containing micronutrients, especially zinc, iron and mangenese during January before bloom, in May after fruit abortion, and again in September to finish fruit sizing.
Watering: In desert locations, irrigate regularly especially during summer. Water much less frequntly during winter.
Pruning: None, except to lightly head back branches as needed. Allow foliar canopy to extend tot he ground so that foliage can protect sensitive trunks from sunscald damage.
Propagation: Mostly grafted or budded onto regionally adapted rootstock.
Disease and pests: Many root rot pathogens if soils are chronicall wet.
Additional comments: Grapefruit trees prosper in a warm subtropical climate. There are several grapefruit cultivars that are ideal for growth in Arizona.
Special note: Secondary compounds in grapefruit have the unsettling characteristic of increasing the efficacy of certain medicinal drugs that are taken orally.
