Botanical Overview
A member of the legume family (Fabaceae), the Ceratonia genus has one species, Ceratonia
siliqua: Carob. About 50 cultivars have been developed around the world.
Description
Form:
Tree.
Lifespan:
80-100 productive years.
Leaf retention:
Evergreen. Some leaves may turn yellow and drop in severe drought situations.
Growth rate:
Slow to moderate.
Mature Size:
30-40' (9-12m) high and as wide or wider.
Flowers:
A few cultivars have bisexual flowers that are self-fruitful. Most have separate male and
female flowers, with a course bottle-brush structure, on different trees. The male flower
parts and flowers have a semen-like odor, mild to some, strong to others, to attract insects.
Pollination is by wind and insects. The flowers appear on spurs of old branches and on the
trunk.
Bloom:
Fall.
Self-fruitful:
Some cultivars are bisexual and self-pollinating, others need both a male and a female tree
to produce fruit. Male trees do not bear fruit.
Years before fruiting:
6-7 years.
Fruit:
A long, green turning to brown, edible seed pod with a flavor reminiscent of chocolate when
ground without its seeds. Each pod holds 5-15 seeds.
Months for fruit to ripen:
11. Dried pods should be harvested quickly after they turn fully brown if rain is likely.
Brown pods ferment on the tree when they become wet.
Yield:
Pod yield increases with the age of the tree: 5 lbs (2.3 kg) at six years, 100 lbs (45.4 kg)
at twelve years, up to 500 lbs (226.8 kg) at twenty years for some cultivars with certain
orchard management techniques.
Storage after harvest:
Keep in a dry, ventilated location. The pods can be stored for several months.
Leaves:
Oval, green, thick leaflets, providing heavy shade.
Stems:
No thorns.
Roots:
This tree has a deep tap root and aggressive surface roots.
Cultivars of Note:
'Clifford' Self-fruitful, excellent flavor, large
crop with irrigation.
'Santa Fe' Self-fruitful, excellent flavor.
Most nurseries sell self-fruitful carob trees without a cultivar name. Check to make sure
whether the tree is self-fruitful, a male, or a female. The self-fruitful will smell when
flowering and have seedpods. The male will also smell but have no seedpods. The female will
not smell when flowering and will have no seedpods without a male or a self-fruitful tree
being present.
Wildlife:
The flowers attract insects. The seedpods are eaten by mammals.
Toxic / Danger:
No. Unlike chocolate, the seedpods of the Carob tree are safe for animals and dogs to consume.
The seedpod husk and seeds contain some tannin, but no caffeine or theobromine.
Origin:
Mediterranean region.
Cultivation and Uses
USDA hardiness zones:
9-11. Young trees suffer frost damage. Older trees are hardy to 20°F (-6.7°C).
Chill hours:
None.
Heat tolerant:
Yes.
Drought tolerant:
Yes.
Sun:
Full sun. This tree is shade intolerant.
Planting:
Locate the tree where it will get full sun all day, no shade, and the soil is well draining.
Avoid any area getting frequent irrigation, such as a lawn. Mature trees in the ground cannot
be transplanted because of their taproot. Surprisingly, this tree can be grown in a large
container.
Soil:
It needs well draining soil, but is tolerant of soil types otherwise. A pH of 6.2-8.6
(slightly acidic to alkaline) is best. This tree is salt tolerant.
Fertilize:
Fertilization is unnecessary, but organic fertilizer can be applied once a year in late
winter. Carob trees are highly successful in their ability to extract nutrients from poor
soil.
Water after becoming established:
Deep water once a month from the third year on.
Seedpod production requires slightly more frequent irrigation, but in summer, this tree needs
irrigation reduced to once a month. It evolved in a region with moderate winter rain and
infrequent summer rain. It is prone to fungal infections in soil that does not dry quickly or
is watered too frequently.
Mulch:
Never. The soil must dry quickly and this tree's roots tolerate high temperatures.
First Two Year's Care:
Deep water weekly in warm months during the first year in the ground to establish a strong
root system. Deep water at least every two weeks in the second year.
Prune:
Flowers appear on old wood and the trunk. Trim branches that touch the ground and dead wood
from the previous winter. Trim lightly to shape in the first few years. Carob trees generally
do not need pruning.
Litter:
Moderate: flowers, leaves and seedpods.
Propagation:
Carob is considered difficult to propagate.
Cuttings from bisexual or female trees can be treated with IBA rooting hormone and planted
mid-spring in a polythene tunnel with water misting.
For seed, file a groove 1-2mm in length into the coat (scarification), then soak in water
for one hour before planting.
Some sources recommend germinating the seed in a forestry seedling tube, however the taproot
is delicate and transplanting must be done with care.
Uses:
Ornamental, edible seedpods, shade tree. The dried pods are naturally sweet and can be eaten
raw by carefully biting around, and spitting out, the hard seeds. The dried pods, without the
hard seeds, are ground into a sweet, chocolate tasting, caffeine free powder. The powder is
nutritious, low fat, and has no bitter flavor components. The seeds are processed into an
edible gum used as a thickener called locust bean gum. The whole pods with seeds can also be
ground into a nutritious flour.
Comments
The seed pods are often used for animal fodder.
In ancient times, the carob seed was used to measure weight because of its
uniformity. The word carat, a unit of weight, comes from the same Greek word as carob.
Because a pure gold Roman coin, the Solidus, weighed 24 seeds, the carat also became used to
define the purity of gold, with 24 carat being pure.
Carob is distantly related to other Legume family members with edible bean pods
or filling, such as
Guamuchil,
Pacay, and
Tamarind.
Do you have additional information or a different experience for these plants that you would
like to share? Email info@GardenOracle.com. All contributions are welcome and appreciated.