The degree of overlap between a plant’s blooming times during its mating season and what would be predicted to happen randomly under specific environmental conditions is known as flowering synchrony. More plants than would be predicted by chance are blossoming (either generating pollen or receiving pollen) at the same moment in a population that is flowering synchronously. Fewer plants than would be predicted randomly blossom at the same time in a population that is flowering asynchronously. In a community, blooming synchronisation refers to the timing of flowering seasons within a single year, between years, and across different species. Across pollination syndromes, coordinated blooming is a common phenomena with both advantages and downsides for fitness.
The occurrence of coincident, simultaneous blossoming of every population of a certain species over a wide area is referred to as synchronous flowering. Many plants might be included, although not necessarily all of that species.
Despite regional differences in weather circumstances, many plant species require pollinators in order to cross-pollinate and generate seeds. As a result, flower development in different plant species is often synchronised, and all mature individuals of the same species bloom at the same time. Although such synchronicity may result from reactions to weather-related conditions, it may be an evolved response to improve reproductive success.
During years with robust blooming responses, synchronised flowering of a species over an area may improve fertilisation and seed set since a larger flower density enhances the likelihood of pollination. Additionally, owing to predator satiation, synchronised blooming may decrease the percentage of seeds attacked by seed predators. The resultant pattern reduces the percentage of seeds lost to predators in a selectively beneficial way.
In addition, some plants from different species living in the same area may simultaneously exhibit similar typical adaptations for an environment with very low pollination probability, converging into parallel phenological patterns, and synchronising their blooming cycles to increase pollinator attraction.
For instance, certain cactus species only bloom once a year (or in a few cyclical periods), and their blooms only last a few days. As a result, flowering tends to be highly synchronous, with the majority of stems in a population producing flowers on any one day.
Another illustration would be the simultaneous blossoming of spring ephemerals and bulbous plants (such as narcissi and hyacinths).