What is the initial value of the birthdate control? If it’s an empty string, the placeholder works for me, albeit without any other attributes than formControlName and placeholder.
Personnally I could never get the placeholder to work on <ion-datetime>.
What I do instead is using the method read there:
Which pre-fill my value with the current datetime in ISO UTC format (and then I do simple JS operations like split to re-format it like I want, combined with ngModel).
Me neither I don’t use labels, it’s kind of a misunderstanding. It’s hard to tell whithout seeing your view code, but if you can prefill the [ngmodel] with a prepopulated value like I did, you don’t really need it, the <ion-datetime> will be correctly filled with whatever value you want (BUT it should be in ISO-68… string, anyways so that it pre-fills).
After, <ion-datetime> can be translated easily by arrays if that’s the issue (see DateTime Ionic docs --> Month Names and Day of the Week Names). And you can combine it with translate pipes too.
@ericbl Then explain it above the select with simple plain html. I was explaining prefill because it helps, when you want to use (ng-model) and pass that value later. And that, simply placeholder does not work on ion-datetime (on Ionic 2).