Can I white wash a stone patio?

Seal it first, then apply your white wash/paint.

Yes, but the question is when you go to sell the house will the buyer like the “white wash”.

In my neighborhood; we had a neighbor the painted their red brick “Navy Gray”. All the trim paint and front door is white, it looks like a prison building.

@Tropical_Willie Makes a good point. It might be better to leave it as it is.

@Tropical_Willie Thank you for that description. Lol.