Bee on Tithonia

A little garden safari today to find a quick blip resulted in this bee on my Tithonia flowers on the patio. The foliage on this single plant in a pot is really scraggy but I don’t know why. It gets plenty of sun(when it’s out), water and gets fed once per week so I have no clue why. The one in the bed is behind for flowering but looks much healthier. Maybe it was dodgy compost? At least the bee seems to be enjoying it.