We know that insects visit flowers to collect nectar and thereby help in 'pollination' which is essential for the survival of plants.
What is amazing is that plants and their “insect visitors” seem to have a 'time agreement' which is precise to the hour. It is only during this agreed period that the insects visit the flowers, and the flowers in their turn, produce the nectar and pollen so that neither the visit of the insects, nor the pollen is wasted. This clock evidently is quite independent of the weather.
Based on this finding the Swedish botanist Carl Linnaeus planted a flower clock in his garden. Carefully chosen plants were arranged in segments around a circle in the order of their blooming time.