It all depends on how much of a peacock you want to be, and how it fits into the rest of your outfit. If you're Luca Rubinacci, for instance, you can probably get away with something more foppish than if you are one of the regulars in the CBD thread.
you hit up shorts or linen pants,etc for most of spring/summer? I've been trying to do some loose linen every now and then and it's still making me sweat. and you're farther south than me. speaking in the day of course, night is a fine.
Fuu, don't really know if you're serious or not, but knit tie and OCBD is definitely not dressy.
Stop listening to what the internet tells you.
Basically, yeah, poplin is dressier but since oxford cloth is warmer it is something you wear in winter+cold part of spring+cold part of autumn. You can wear it with a suit or more casually, hell even button downs are worn with suits, it being a pretty well implanted American tradition. In other words it is interchangeable with the supposedly dressier fabric but you wouldn't be expected to wear it in the evening or when meeting the president if you were a British gentleman, in reality no one cares. Knit tie is just a tie you wear when its cold, still goes with a suit and all but yeah, if you are going to be meeting the president, wear a regular tie, aside from that, once again, who cares. So these two items are only ever so slightly more casual than poplin dress shirt + silk tie. Jeans with wear marks and suede or whatever shoes are totally casual though, no question about it. BTW wearing a dress shirt (OCBD or not) + sportcoat + slacks+dress shoes isn't "casual", it was in a certain milieu in 1965, now it is called being dressed up, it is just not as formal as a suit. At some point in time dressy was a tuxedo or even tails.