he spotted a baby white pine growing along the side of the road.

If there is any way of discovering the general location of the
source of the Italian's white pine sapling then travel the area to
scout for other white pines.

I frequently get "volunteers" in my flower beds, for some reason
they especially like growing out of "blue rug" junipers. The first
one I found when I moved in was 6" high when I first saw it, and
about a foot tall when I replanted it and is now taller than I and
quite happy only a few years later.

Find another tree looking out of place (growing in a strange or
inappropriate spot) and give it a better home, and by doing so
remember both the first tree and the gardner who felt moved to
plant it...

I also think you'll have better luck with a sapling than starting
from seed. Spring and fall are the best times to move a tree,
if you feel compelled to do this in midsummer then water it like
crazy.

--Glenn Lyford