Ceratonia

( sair - ah - TOH - nee - uh )

At-A-Glance Information

Commonly called Carob or St. John's Bread, this evergreen shrub or tree needs full sun and little water to perform well in the landscape. These are very drought tolerant trees, and once mature can get by on rainwater alone. Species are native to the Mediterranean and the Middle East, and have been introduced to many other areas around the world with similar climates. These trees are wonderful in drought-tolerant landscapes or xeriscaping, and are also useful as windbreak.

Ceratonia species and varietals

The genus Ceratonia (formerly Acalis) is a member of the plant family Fabaceae and includes just 2 species. The genus was thought to be monotypic until a second species (Ceratonia oreothauma) was discovered in Oman and Somalia in 1979. Carob trees grow well in USDA hardiness zones 9-11 or Sunset growing zones 9, 13-16, 18-24, and H1. To find your zone, click here: Zone Map.

Ceratonia oreothauma (Carob Tree)
Native to Oman and Somaliland, this small tree has gnarled branches and bark, and reaches about 26 feet tall when mature. Flowers appear between March and April in the plant's native range. Blooms are small and white with a yellow center. These trees are predominately dioecious.

Ceratonia siliqua (Carob Tree, Algerrobo, Algorroba)
These plants reach 20 feet tall in about 10 years, and eventually rises to 30-40 feet tall and wide. The roots of these trees will break up concrete. Foliage is dense, glossy and dark green and springtime flowers are red. Female trees will drop many flattened brown seed pods after flowers fade. These pods are milled and turned into a chocolate substitute called carob. Carob trees are hardy down to 18 degrees Fahrenheit, and when young will need good frost protection. 'Clifford' is a self-fertile variety. This species is considered to be an invasive tree in California, Arizona, Texas, and Florida.

Caring for ceratonia

Ceratonia plants should be situated in full sun; they will require at least 6-8 hours of direct sun each day to flower and produce well. These trees are adaptable to a wide variety of soil types, though ideally soil should be loamy or sandy and well-draining. These trees prefer soil to have a pH of between 6.2 and 8.6 (slightly acidic to slightly alkaline). Avoid planting Ceratonia in a spot where water frequently pools; they do not like to have wet feet and will develop root rot in these conditions. Apply a 2-3 inch layer of mulch to the top of the soil, taking care to keep it a few inches away from the trunk. This will help to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Newly installed trees should be watered regularly up until they reach about 3 years old. These trees are drought-tolerant when mature, but will need this consistent moisture when young to help them develop a strong, deep root system Mature trees need deep waterings occasionally during extended periods of drought but can otherwise survive off of rainwater alone.

These trees do not require much fertilization; If grown in poor soil, make sure to amend with a generous amount of compost before planting, and repeat applications yearly in early springtime. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Carob trees require minimal pruning; simply take off dead, damaged, or diseased branches in late winter or early springtime. Shape tree if necessary when pruning. These trees will naturally develop wide, spreading canopies, and light prunings can help to maintain structure without compromising growth. Carob Trees are considered long-lived in the landscape, able to produce for between 50 and 100 years or more before needing to be replaced.

Harvesting Carob
Female Carob trees produce long, leathery pods that are ready for harvesting in late summer or fall. They look like large beans, and emerge green, darkening to dark reddish-brown when ripe. These pods take about a year to develop, and flowers and ripe pods are present on trees simultaneously. In order for female trees to produce pods, there needs to be a male specimen nearby. Picking pods from trees and shaking branches are basic ways to harvest ripe pods, or they can simply be picked off of the ground. After harvesting pods, make sure to check them for diseases, mold, or insects. Carob pulp is sweet, and has a taste reminiscent of chocolate (though if you're expecting a perfect taste match, expect some disappointment).

Raw pods can be chewed as a great snack. Seeds within the pods are very hard, and don't have the same flavor. Place pods in a large bowl and rinse them a few times. Drain the bowl, and lay pods on a flat surface in the sun for between 48 and 72 hours. Next, crush the pods to release the seeds, and separate them from the pulp. The easiest way to do this is to use a rock or other blunt object like a meat tenderizer, and give each pod a few good whacks. Place the pieces of carob pod (without the seeds) into a coffee grinder and grind them as fine as possible. Next, use a fine mesh to sift out larger pieces until the consistency is about the same as cocoa powder. Flour sifters are fantastic for this purpose. Then use the Carob in any recipe that calls for cocoa powder.

Disclaimer: Information contained on this website is strictly and categorically intended as a reference to be used in conjunction with experts in your area. Foraging and consumption of plant parts should never begin without the guidance and approval of a local plant specialist. The providers of this website accept no liability for the use or misuse of information contained in this website.

Propagation

Ceratonia trees are most easily propagated from seed. To propagate your tree, follow the instructions below:

Propagating Ceratonia by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. The seed pods on Carob trees are pretty easy to spot, they're large and dangle from the branches, left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Alternatively, pods can be harvested and crushed to release seeds.
Ceratonia seeds have a hard coating that protects them, but this coating also makes it a little difficult to get them to germinate. We can help the process along by scarifying them with sandpaper (or simply rubbing them against an abrasive surface) or by nicking the seed coat. Do this with as many seeds as you can; they will probably not all sow, and the ones that do will be of varying characteristics. The more seeds you plant, the more chances you will have to get the resulting plant you want. Place your seeds in lukewarm water for 24 hours. Viable seeds will sink to the bottom, and non-viable seeds will float to the top. You can discard any seeds that float.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Ceratonia seed pods still on the tree.

Ceratonia seeds are small and reddish brown to golden in color.

Problems and Pests

These trees do not have many pest or disease issues, though they can be considered somewhat problematic themselves. Ceratonia trees have invasive surface roots which can damage sidewalks and driveways if planted in close proximity. The seed pods produced by female trees also can create a mess when they fall in autumn. Furthermore, they can spread through free seeding and are considered aggressive colonizers of disturbed habitats. They are considered invasive in California, Arizona, Texas, and Florida; check with local authorities before planting. Ceratonia plants are susceptible to damage from the following pests and diseases: