i would not write that the venue requires formal attire because although country clubs often have a dress code, it usually does not mean suits or tuxes. i think mine says no shirts without collars except those that are tennis or golf specific.
this is not from my venue but this is typical country club dress code:
i think if you said the venue had a dress code, some people might show up dressed like serena williams or tiger woods.
if i was concerned with guests showing up in jeans, i would just write “semi-formal attire” or “cocktail attire” or whatever attire you decide on and leave out the required or suggested part. no one would be offended and some will actually find it helpful. i know my group of family and friends so i didn’t include the attire on my invites. if i wrote black-tie, some will still show up in suits or short dresses and it would make the ones in tuxes and full length dresses feel out of place. i also know that no one will show up in jeans (even if the jeans were $300). i’m from southern california and although we do love our fancy expensive denim and track suits, we would never even think about wearing them to a wedding we love getting dolled up and a wedding is just another excuse to do so.
my only concern was the rehearsal. i wanted to make sure everyone showed up wearing appropriate attire – no tank tops or flip flops. a few of the guys will be golfing after the rehearsal so they will be wearing appropriate golf attire.
whether you choose semi-formal or cocktail, please make sure you understand what each means. there are noticeable differences betwee white tie, black tie, creative black tie, semi-formal, cocktail, business casual…
semi-formal is actually closer to black tie than cocktail. for semi-formal, tuxes are not requiredfor men but you still have to wear a dark suit and while full-length dresses are not required for women, nicer luxe fabric and tailored dresses are. cocktail is actually less dressy than semi-formal. men do not have to wear suits but can opt for slacks or sports coats, and neckties are not required. women will often wear sexier dresses for cocktail.
i actually prefer semi-formal because it gives people the option of wearing a tux and not feel like they are a part of the wedding party but does not require those who do not own own to go out and rent it. and for women, it gives us the flexibility of finding the perfect full-length dress but does not limit us to just full-length. but shorter dresses should still be knee length or longer and should not be too revealing. think more like the formal dress shop in nordstroms (adrianna pappell, abs, calvin klein…) cocktail on the other hand can be a dress from the juniors section – short length, tight, and with more skin showing.