Sir and Rumi Carter posed with Mom surrounded by a rose-filled trellis in an oceanside location -- it looks a lot like the grounds of the Malibu palace where we know Bey and Jay have been living since the kids were born.

It's been about a month since the little boy and girl arrived. As we first reported ... they were hospitalized for a while after birth to get treatment for jaundice.

Not only do they look totally healthy now ... check out the full head of hair on one of 'em!

Congrats!