Q. Why do some variegated plants grow back without the original patterning after pruning?

A. Variegation, in the form of the familiar dark and light patterning of leaves in some plants, results from variation in the presence or absence of chloroplasts, the bodies in a cell that use the green pigment chlorophyll to produce sugar through photosynthesis.

A common cause of variegation is that a leaf can have more than one kind of genetic makeup in cells in the same tissue system, making the plant what is called a chimera. The cells with genes that produce active chloroplasts are green, and those without are white or another color.