How Does Carob Flowering and Pollination Happen?
Carob is known as the only tree among Mediterranean trees whose main flowering period coincides with autumn. During this period from September to November, small, fragrant flowers bloom on the trunk and old branches; It is pollinated by insects such as bees, flies, hornets and night-flying moths, and partly by wind.
In this article, we explain the flowering calendar of carob, the function of the scent of flowers, the share of insects and wind in pollination, why fruit set is low and how pods develop from fertilization to harvest in the light of scientific studies.
When does carob bloom?
While the majority of fruit trees in the Mediterranean bloom in spring, carob is excluded from this order. In the monograph published by IPGRI, it is emphasized that carob is the only Mediterranean tree whose main flowering period is autumn (September-November), and in this respect, it is similar to many tropical plants (Batlle and Tous, 1997). Dafni et al. also state that carob blooms mainly between September and December.
The time and duration of flowering vary according to the local climate. In the monograph, it is stated that in very hot places, male and female trees are observed in full bloom even in June, and in some regions, the flowering partially overlaps with the flowering of the loquat (maltese plum) tree. The flowering of commercial female varieties can be spread over 3–4 months between August and November (Batlle and Tous, 1997).
The long flowering period has a function. The unstable weather of autumn is not always suitable for pollination. According to the monograph, spreading flowering over a long period secures pollination of at least some flowers in short intervals when the weather is favorable and insects are active.
Formation of Flower Buds
Flower formation in carob begins long before autumn. According to the hormone studies cited in the monograph, the transition from vegetative growth to flower formation may be associated with low gibberellin levels in June. In addition, the pod load carried on a tree that year can suppress flower formation in the same season; In Portugal, it has been observed that in 30–40-year-old 'Mulata' trees, pods inhibit flower differentiation, especially during the rapid growth period between April and June, in crop-laden years (Batlle and Tous, 1997). This is one reason for the "one year abundant, one year less" crop pattern (periodicity) that is common in carob.
Flower Structure and Clusters
Carob flowers are small, reddish-green flowers without petals. They form in catkin-like clusters, on short shoots on old wood and directly on the stem. According to Daphni et al., the strong-smelling panicles carry about 20–50 flowers and can be easily taken up by insects because the nectar lies exposed on a large disc.
Trees can be male, female or hermaphroditic according to the type of flower. It has been reported that female and hermaden clusters carry an average of 17 and 20 flowers in Spanish varieties (Batlle and Tous, 1997). We discuss the details of flower types in our article "Male, Female and Male Trees in the Carob Tree".
The Scent of Carob Flower
Carob flowers have a distinct and heavy smell. The IPGRI monograph states that male and herbaceous flowers emit a semen-like odor that attracts insects. This smell, noticed by those who pass by carob orchards on autumn evenings, is a signal that the plant uses to attract pollinators.
In a study conducted in Portugal, volatile compounds emitted from the flowers of male, female and herbaceous trees were analyzed and more than 25 compounds were identified. Monoterpenes and sesquiterpenes constituted most of the fragrance; linalool and its derivatives, alpha-pinene and alpha-farnesene came to the fore. It was determined that the variety of compounds was higher in female flowers and the amount of main compounds was lower; it was determined that the main source of the odor in all three flower types was the nectar disc (Custódio et al., 2006).
How is carob pollinated?
The transport of pollen from the male flower to the female flower in carob occurs in two ways: insects and wind. In the scientific literature, the use of these two pathways together is called "ambophilia", and this concept is included in the title of the study published by Dafni et al. on carob pollination.
Insect pollination
According to the IPGRI monograph, pollen transport is provided by insects, mainly bees, flies, hornets and night-flying moths; different groups of insects visit the flowers at different times of the day. However, autumn is a period when bees are reduced in both species and number of individuals. Dafni et al. also describe autumn flowering as a "challenging pollination environment" due to climatic conditions, few potential pollinators and few individuals.
In a two-year study in Cyprus, it was observed that the most frequent visitor to flowers was the honey bee (Apis mellifera), followed by wild bees and hornets. At least 10 different species of wild bees visited carob flowers (Varnava et al., 2023). Another study conducted in 20 gardens in Mallorca found that gardens surrounded by natural areas received more visits from wild bees and butterflies and fewer honey bees (Gómez-Martínez et al., 2025).
Nectar is the most important reward of carob flowers for insects. All three flower types are known to secrete nectar. In the evaluations based on studies in Spain, it was reported that female flowers had higher nectar volume and sugar content (Batlle and Tous, 1997), while in a study conducted in a forest in Jordan and published in Uludağ Beekeeping Journal, it was found that male trees produced more and denser nectar, and it was observed that honey bees frequently visited carob for pollen and nectar (Maha and Haddad, 2012). These results also show that carob is a valuable food source for bees in autumn.
Wind pollination
The IPGRI monograph states that wind also plays a role in pollen transport, and that female trees left alone can produce light crops, but it is not known to what extent wind-borne pollen is effective. In the investor guide of the Ministry of Agriculture and Forestry, it is stated that carob is generally pollinated by wind and is an anemophilous (wind-pollinated) species.
However, current field studies show that the share of insects is much larger than that of the wind. In the study in Cyprus, 4 to 16 times more pods were obtained from the exposed flowers, depending on the region, compared to the flowers whose inflorescences were covered with a thin mesh bag and left to be pollinated solely by the wind. The pods formed by open pollination were also heavier, longer, and more seeded (Varnava et al., 2023). The authors of the Mallorca study also describe carob as a pollinator-dependent Mediterranean crop (Gómez-Martínez et al., 2025).
When these findings are evaluated together, it seems more accurate to say that wind plays a complementary role in carob and insect pollination is decisive for commercial yield.
Environmental Factors Affecting Pollination
The autumn flowering of carob makes pollination sensitive to weather conditions. The IPGRI monograph states that autumn rains can inhibit pollination and affect fruit set. Wind and precipitation limit both the transport of pollen and the flight of insects.
The main factors affecting pollination success can be listed as follows:
- Rainfall, wind and low temperature during the flowering period
- Whether there are male or female trees in and around the garden
- Overlap of flowering times of male and female trees
- Number and diversity of pollinator insects
- Level of conservation of surrounding natural areas
- Germination power of pollen
Pollen quality also varies from tree to tree. In the monograph, it is stated that pollen germination in wild male trees in Crete varies between 4.3 and 69 percent under laboratory conditions, while in another study, it is found to be in the range of 5.2-38.6 percent in males and 7.1-26 percent in male types (Batlle and Tous, 1997).
The coincidence of harvest period and flowering is also an issue to be considered. Carob harvest is usually done in late summer and early autumn, and the trees are in flower at this time. In the monograph, it is emphasized that when shaking the pods with a pole, the flowers may be damaged and the next year's crop may be partially destroyed.
Why is Fruit Set Low?
Only a small part of the flowers blooming in carob turn into ripe pods. According to the IPGRI monograph, the general fruit set in Italian, Portuguese and Spanish varieties is mostly around 3-5 percent; it has been observed that it decreases to 1 percent in some years and to 0.05 percent in very abundant flowering years. It has also been reported that pods with few seeds fall more frequently.
In a detailed study conducted on two female and two hermaden varieties in northeastern Spain, it was determined that between 12.6 and 35 percent of the flowers initiated fruit formation, but between 79.2 and 90.2 percent of the fruits that started to form fell before ripening. Flower and young fruit drop was high between October and December, slowed down in January and February, increased again until May and almost stopped between June and August (Bosch et al., 1996). In the same study, it was observed that fruit formation, fruit set and seed setting rate per flower were higher in large clusters than in small clusters.
According to the evaluations conveyed in the monograph, changes in flowering intensity and pod yield are related to internal factors related to periodicity rather than climate. However, adverse environmental conditions may reduce fruit set and increase the risk of production, especially in orchards in border regions.
From Fertilization to Harvest: The Development of the Pod
The process from fertilization to mature pods in carob takes about 10 months. According to the studies cited in the monograph, pod development follows an S-shaped growth curve, as in many fruits, and is divided into three phases (Batlle and Tous, 1997):
| Phase | Semester | What happens? |
|---|---|---|
| I. Slow growth | Autumn and winter | The weight of the young pod in the fertilized flower almost never increases. |
| II. Rapid growth | April–June | The pods quickly stretch and thicken. |
| III. Maturation | From June | Growth slows down, the pods begin to dry out, the color changes from green to brown. |
A similar pattern was observed in the study in Spain; slow growth between December and March, linear growth between April and June, and slow growth and ripening phases between June and August were defined (Bosch et al., 1996). While the water content in green pods is approximately 70 percent, it decreases to 12-18 percent in ripe pods. The ministry guide also states that fruits start to grow at the beginning of May, ripen in June-July and are harvested from September.
This calendar has a practical consequence: Flowers that bloom in one autumn turn into pods that can only be harvested at the end of summer of the following year. Therefore, both ripe pods and newly bloomed flowers coexist on the tree during harvest.
Supporting Pollination in the Garden
The findings in the sources point to several basic principles to support pollination in carob orchards:
- Placing male or male pollinator trees in the garden at regular intervals
- Flowering time to cover the long flowering of female varieties using different pollinators
- Protecting natural vegetation around the garden
- Being careful not to damage the flowers during harvest
The IPGRI monograph states that hermit pollinators are generally more successful in terms of flowering overlap with female varieties, as male trees have a shorter flowering time. In the Mallorca study, it was observed that seed weight increased in gardens surrounded by protected natural areas, and wild pollinators were more dominant in these gardens (Gómez-Martínez et al., 2025).
Frequently Asked Questions
What month does carob bloom? The main flowering period is usually September–November. Depending on the region and variety, flowering can extend from August to December.
Is carob pollinated by wind or insects? It is pollinated with both. However, the field study in Cyprus showed that 4 to 16 times more pods were formed in the flowers accessible to insects; this shows that insect pollination is decisive for yield.
Why does carob flower smell bad? Male and herbaceous flowers emit a heavy odor that serves to attract insects. This odor is caused by volatile compounds released from the nectar disc of flowers.
Is carob important for beekeeping? Yes. Carob offers nectar and pollen in the fall, when many plants end their flowering; studies show that honey bees and numerous species of wild bees frequent carob flowers.
From Flower to Product with Carob Türkiye
The small flowers of the carob, which bloom in autumn, develop into sugar-rich pods and valuable kernels after about ten months of development. The success of pollination directly affects the quantity and quality of both the fruit flesh and the kernel.
At Carob Türkiye, we supply carob fruit, crumbs, flour/powder, seeds and extracts. Our product range Our Products You can review the connection of carob with beekeeping. What is Carob Honey? You can read it in our article. For your wholesale and export requests Contact Now You can contact us on our page.
Domestic resources
Republic of Turkey Ministry of Agriculture and Forestry, General Directorate of Forestry, "Carob Orchard Facility Project Feasibility Report and Investor Guide", Ankara, 2020. Eskisehir.
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handle. net/ 11452/ 15871 Foreign sources
Batlle, I., Tous, J., "Carob tree. Ceratonia siliqua L. Promoting the conservation and use of underutilized and neglected crops. 17", Institute of Plant Genetics and Crop Plant Research, Gatersleben / International Plant Genetic Resources Institute, Rome, 1997. ISBN 92-9043-328-X. hdl.
handle. net/ 10568/ 104277 Dafni, A., Marom-Levy, T., Jürgens, A., Dötterl, S., Shimrat, Y., Dorchin, A., Kirkpatrick, H. E., Witt, T., "Ambophily and 'super generalism' in Ceratonia siliqua (Fabaceae) pollination", Evolution of Plant-Pollinator Relationships (Systematics Association Special Volume 81), Cambridge University Press, pp. 344–373, 2011. doi.
org/ 10. 1017/ CBO9781139014113. 013 Varnava, A. I., Manganaris, G. A., Stavrinides, M. C., "Assessing the biodiversity and the impact of pollinators on carob production", PLoS ONE, 18, e0291431, 2023. doi.
org/ 10. 1371/ journal. pone. 0291431 Gómez-Martínez, C., González-Estévez, M. A., deCastro-Arrazola, I., Unglaub, P., Lázaro, A., "Landscape conservation and orchard management influence carob tree yield through changes in pollinator communities", PLoS ONE, 20, e0307357, 2025. doi.
org/ 10. 1371/ journal. pone. 0307357 Bosch, J., Del Pino, F. G., Ramoneda, J., Retana, J., "Fruiting phenology and fruit set of carob, Ceratonia siliqua L. (Cesalpinaceae)", Israel Journal of Plant Sciences, 44(4), 359–368, 1996. doi.
org/ 10. 1080/ 07929978. 1996. 10676657 Custódio, L., Serra, H., Nogueira, J. M. F. et al., "Analysis of the Volatiles Emitted by Whole Flowers and Isolated Flower Organs of the Carob Tree Using HS-SPME-GC/MS", Journal of Chemical Ecology, 32(5), 929–942, 2006. doi.
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