So do I really have to grant a wish to make one because it said I could make one every day...

Yup, you need to grant one before you can ask for one. And you can only do that once a day. You can grant more after that but only make one wish a day.

You can make a wish without/before granting one if you're lucky, just need to send at the right time, when the shrub isn't full Granting a wish will simply allow you to make your wish anytime

There are 150 spots at the shrub. If those are taken then you have to wait to make yours when someone has granted a wish. Locking as this is not a bug.