But these responses are interesting and so let's combine a tree
strategy with a solar panel strategy:

If the front of the house faces South then put solar panels on the
front slope of the roof and put one or two hardwood trees in the
backyard.

If the rear of the house faces South then trees are likely naturally
in the backyard and the house is naturally cool. But if there are no
tall trees in the back yard then put solar panels on the rear slope of
the roof and put one or two hardwood trees in the front yard.

If the side of the house faces South and there is no roof slope facing
South then I would put solar panels on a steel pole against the North
side of the house (to get the best angle over distance trees to the
South). Then put one hardwood tree in the front yard and one hardwood
tree in the backyard.