Different flowers yield their nectar at different times of the day (not taking into account weather/temps).
I did see a chart a little while ago on the different times particular flowers yield (some for as little as an hour a day) but can't find it right now. Will have another search.
Not quite the same, Little bees, but Carl Linneaus developed a floral clock in the 18th century. He had noted that some flowers have set opening and closing times, presumably partly to avoid competition for pollinators. There's a lovely list below from a company called Outside Edge, suggesting planting a circular bed with the view to 'telling the time' according to which section flowers is open or closed! Several are bee-friendly.
Floral Clocks were a 19th Century craze – the idea being to plant a circular bed with twelve sections.
The plants in each section would flower in sequence.
If you are tempted to try to construct such a display – have a look at the plant list below:
2:00 AM Night blooming cereus closes
5:00 Wild roses and (the obvious) morning glories,
6:00 Spotted cat’s ear, catmint
7:00 African marigold, orange hawkweed, dandelions
8:00 Mouse-ear hawkweed, African daisies
9:00 Field marigold, gentians, prickly sow thistle closes
10:00 Helichrysum, Californium poppy
11:00 Star of Bethlehem
12:00 Noon Passion flower, goats beard, morning glory closes
1:00 PM Chiding pink closes
2:00 Scarlet pimpernel closes
3:00 Hawkbit closes
4:00 Four o’clock (Mirabilis’ Marvel of Peru) opens, Californian poppy closes
5:00 White water lily closes
6:00 Evening primrose, moonflower
7:00 Difficult
8:00 Daylilies and dandelions close
9:00 Night blooming cereus
attention and "smell the roses"....
