Here was my M-4 the night before the 36° frost visited.
While some trees did get light frost on them, I'm guessing this one didn't. Here's the tree twelve days afterwards:
And now it's got pea-sized fruit. Alas, the tree is only two years in the ground, so these will be coming off this weekend.
My Pickerings all bloomed after the frost. Neelam is just breaking buds.