Members of the Citrus family (Rutaceae), modern Citrus fruits, according to genetic
analysis, are complex hybrids arising from mandarin, pomelo, and citron ancestors, refined by
more than four thousand years of cultivation. Grapefruit was first identified in Barbados, and
resulted from an accidental cross between Sweet Orange and Pomelo. Many cultivars are now
Lifespan: 35-50 productive years.
Leaf retention: Evergreen.
Growth rate: Moderate.
Mature Size: 15-20' high and as wide.
Flowers: White, four petals, fragrant.
All cultivars self-pollinate.
Years before fruiting:
3 for grafted trees, 10 for those grown from seed.
Round to oval, a thick yellow rind, with flesh that can be white, pink or red, aromatic, and
slightly bitter. The red fleshed cultivars tend to be sweeter.
Months for fruit to ripen:
10. Grapefruit may be allowed to stay on the tree after ripening until May.
Storage after harvest:
Up to one week at room temperature or several weeks refrigerated.
Glossy dark green, lance-shaped, smooth margins.
There are short thorns on the twigs. The bark is prone to sunscald if not shaded by the leaves,
especially in higher temperatures.
Usually grafted onto a special rootstock that is pest resistant and adapted to the local
Cultivars of Note:
'Rio Red' - Sweet red flesh, few seeds.
'Oro Blanco' - Sweet yellow flesh, few seeds, easy
to peel, a hybrid of grapefruit and pomelo.
The flowers attract bees and other pollinating insects. The fruit attracts birds. Mammals may
strip the bark off of young trees, consume fallen fruit, or climb the tree to eat the fruit.
The leaves are a food source for the Giant Swallowtail butterfly caterpillar – see
Toxic / Danger:
Possible thorns. Grapefruit can interact with many medications, including chemotherapy, making
them more, or less, effective and throwing off the prescribed dose.
A natural hybrid first recognized in Barbados.
Cultivation and Uses
USDA hardiness zones:
9-11. Somewhat less cold-hardy than oranges.
Chill hours: None.
Heat tolerant: Yes.
Depends on the rootstock. Drought will damage the fruit crop.
Place the tree in a sunny location, but with afternoon shade, away from the coldest part
of the yard. Do not position the plant next to a frequently watered location, such as
grass. Make sure there is enough space for the tree to grow to its full width and height,
with clearance to walk around and where overhead lines will not be a problem.
The best time to plant a citrus tree is after the danger of frost is past, in late
winter or early spring.
Plant the tree so that the root crown is at least one inch above ground level. The top
roots must extend out from the trunk, just above, and uncovered by, soil.
Well drained, can be mixed with aged compost and sand, pH 5.6-8.5 (acidic to alkaline).
Citrus trees are heavy feeders. Apply an organic fertilizer every month from mid-February
to early October. Apply a citrus micronutrient solution three times a year in February,
May and August. Avoid NPK chemical fertilizers because they increase salt build-up in the
soil. Do not fertilize after October to keep the plant from producing new growth that will
be harmed by early frost.
Water after becoming established:
, weekly in summer to monthly in winter,
from the trunk to just beyond the canopy. The top of the soil should dry out between
waterings. Grapefruit trees require 20% more water than orange trees of the same size.
The water should reach 1-2' deep for newly planted trees and 3' deep for trees in the ground
3 years or more. Young trees need watering more often than older trees.
A sign of insufficient water is leaves turning dull with inward curling edges.
Apply organic mulch inside the drip line and 8" away from the trunk to reduce soil evaporation
and reduce root zone heat and cold stress.
Remove sprouts growing on the trunk under the graft as they occur because these are from
the wrong plant. Remove dead, damaged, crossing and weak branches in late winter. When
shaping into a tree, unshaded trunks and branches should be painted with a tree trunk paint
to protect against sunscald.
Keep all grass and vegetation 3' away from the trunk.
Dropped fruit must be picked up immediately to avoid attracting wild animals.
Cuttings grafted onto disease resistant rootstock adapted to the local climate. Trees grown
from seed are usually true to their parent tree characteristics.
Giant Swallowtail Butterfly caterpillar. This larvae resembles bird poop and has white
and black and/or brown splotches. On a large plant it will cause no harm. On a small
plant, relocate it to a large citrus. For other problems, see
Citrus: Diseases and Disorders
Ornamental, edible fruit.
The fruit and flowers pictured are 'Oro Blanco'.
Do you have additional information or a different
experience for this plant that you would like to share?
Email firstname.lastname@example.org. All contributions
are welcome and appreciated.