Just outside the front door of my home is a small ornamental tree that I planted last year. The tree is unusual looking, having a rounded evergreen canopy placed on top of a straight, branchless trunk. In fact, this plant is entirely unnatural, which is why it catches the eye compared to other plants around my home. Instead of being grown as a seedling, it was created by a skilled horticulturalist who grafted a bush-like dwarf pine onto a young white pine trunk. The graft between the two plants is still visible as a bulge near the top of the...