Found this filter almost by accident. I've only tried the 'sky' gradient and played around a bit with the frosted edges.

OK, the sky....there are several options, but only one I really liked. Can choose the color and positioning, very adjustable and easy. Would be nice to throw in a cloud or two but...... No need trying to get the grey out from between the branches of trees, it just works.

The frosted edges come in white, black and colors you can define. There are a couple of other things I haven't played with.

PS, it shows up as 'photo tools' in the filters list.