According to genetic analysis, citrus fruits called lime are complex hybrids arising from
mandarin, pomelo, citron and hystrix ancestors, refined by thousands of years of
cultivation. Key Lime, for example, is a cross of C. hystrix with citron. Persian Lime,
in turn, is Key lime crossed with Lemon. Australian Finger Lime, the exception, is related
to kumquat, but not C. hystrix.
Several citrus species and hybrids are called lime because of their flavor. A few are
in commercial production or sold by nurseries for residential use.
A shrub or small tree.
Possibly 50 productive years.
Moderate to fast.
Citrus x latifolia: 15-20' high and as wide, often only 10-15'.
White, five petals, fragrant to scentless. Reddish buds.
Depends on cultivar. Often spring through fall, possibly all year in regions without freezes.
All lime cultivars self-pollinate.
Years before fruiting:
Grafted: 3-6. Cuttings and air layers: 1 year after planting. Seed: 4-8 years after planting.
Remove all small fruit in the first 3-5 years to speed growth of roots, stems and leaves.
Fruit: Round to oval, sometimes with a nipple at the
Months for fruit to ripen:
5-6 after flowering. Limes are picked green commercially, but most are mature when the skin
is light green or pale yellow.
Storage after harvest:
6-8 weeks in refrigeration.
Oval to lance-shaped, glossy green, slightly fragrant.
Thorny to thornless depending on cultivar.
Sometimes grafted onto a hardy rootstock.
Species / Cultivars of Note:
Citrus australasica: Australian Finger Lime –
cylindrical fruit filled with fleshy, round vesicles, fewer, separate seeds, and an
enjoyable lime-like flavor. Hybrids with other citrus species have produced a variety of
rind colors, including red. This species is known as lime caviar because the flesh is made
up of small, round, thin-skinned drops. The tree has noticeably smaller leaves.
Citrus x latifolia: Persian / Tahiti / Bearss Lime
– larger, oval fruit, seedless, dark green to light green at maturity, milder flavor,
Citrus aurantiifolia: Sweet / Palestinian Sweet
Lime – lemon-sized fruit, light green to yellow at maturity, refreshing sweet
juice lacks acidity (sourness), a plant that deserves wider residential use, and some would
say, better tasting than Persian or Key lime;
Citrus aurantiifolia: Key / Mexican Lime –
Very frost sensitive, small round fruit, the standard for lime flavor, yellow at maturity,
limited commercial production;
Citrus aurantiifolia x japonica: Limequat –
a small hybrid of kumquat and Key lime, with a lime-like flavor, somewhat more cold hardy
than Key lime but not as hardy as kumquat. The rind is sweet and edible. Many consider this
highly productive plant to be the best residential lime;
Citrus hystrix: Thai / Makrut Lime –
its fragrant leaves are used in Asian cooking. The fruit of this ancestral species has bumpy
green to yellow rind used in Asian curry and Creole cuisine, and unpalatable fruit juice
used in shampoos and believed to kill head lice.
Wildlife: The flowers attract bees and other pollinating
insects, and the leaves are food for the Giant Swallowtail butterfly caterpillar – see
Pests, below. Mammals may strip the bark off of young trees, consume fallen fruit, or climb the
tree to eat the fruit.
Toxic / Danger: For some cultivars, exposure to the rind
oil or tree sap, and sunlight, causes dermatitis in sensitive individuals. Possible thorns.
Cultivation and Uses
USDA hardiness zones:
9-11 for Persian Lime, Sweet Lime, and Limequat; 10-11 for Key Lime and Finger Lime.
Chill hours: None.
Heat tolerant: Yes.
Depends on rootstock. Drought will damage the fruit crop.
Full sun with afternoon shade, except for Finger Lime which is an understory shrub or small
tree that needs shade most of the day.
Place the tree in a sunny location, but with afternoon shade, away from the coldest part
of the yard. Finger Lime needs part shade most of the day in high temperatures. 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.
Lime trees can be grown in containers.
Well drained to prevent root rot, pH 5.6-6.5 (acidic to slightly acidic). Alkaline soils
will cause iron deficiency.
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 chemical
fertilizers because they increase soil salinity. 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. 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.
Use organic mulch to protect evaporation during hot weather, and protect roots in winter.
Keep mulch 6" away from the trunk to avoid collar rot. Place a rodent gnaw guard around
the trunk at the bottom.
First Year Care:
Water at planting, then every other day for the first 8 weeks, then twice a week for the
first 3 years, coordinating with rainfall.
Citrus trees are best grown as shrubs, so that leafy branches protect their entire trunk
from direct sun. Only prune the lowest branches if their tips touch the ground. If you
prune up from the bottom to expose the trunk, you must paint it with a tree trunk paint
to avoid sunscald. Prune only after danger of the last freeze is over in late winter or
early spring. Never prune in the summer.
Keep the soil under the drip line free of grass and other plants that can compete
for water and nutrients.
Low. Fruit if not harvested.
Cuttings grafted onto rootstock. The seed of Key Lime grows true, other cultivars may not
and may be sterile.
The Giant Swallowtail Butterfly caterpillar 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.
See Citrus: Diseases
Fruit, ornamental, shade.
This website uses World Flora Online
as the definitive source for plant species names.
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