It’s bad enough that I have to paw through all my reference works trying to separate similar species of birds… at least with birds there can be different songs or behaviour to help. It’s hard enough telling one bee from another, or separating hoverflies! Turns out the plant kingdom is just as bad. These two blue beauties are a case in point.
Blue Leadwood Ceratostigma plumbaginoides
Chinese Plumbago Ceratostigma willmottianum
Although I guess ‘behaviour’ is a factor in as much as one tends to be prostrate and the other forms a shrub-like bush. I think the blue is stunning although its not much of an attractor of insects despite a few hoverflies nosing around.
Some species certainly prefer different flowers, and In suspect some are specialist in colours. I’ve notice this hoverfly often goes to the purple petunias but ignores the red ones?