I have just come in after observing Z Canis Majoris on and off in very mediocre Seeing and the best I can say was a maybe in periods of better seeing
When returning to the star after a little time away a faint haze was seen but then the brightness of the star itself overwhelmed the nebulosity the more you looked at it.
Eye pieces used 6mm Radian and 2.5 mm Barlow
Needs better seeing I think to get a definite yes or no.
Cheers