grow light for outdoor plant

Is it crazy for me to use a CFL grow bulb to boost the growth of an immature gold thread false cypress? I planted three of these specimens this spring in front of a bay window. One of the shrubs is in mostly a shaded area, but does get indirect/partial daylight whereby the other two get full sunlight .With all other factors being equal, the shaded plant is not growing as quickly as the other two that get alot of sun. False cypress has a slow growth rate to begin with, and b/c I want the shrubs to have a uniform appearance I thought about a supplemental light source for the one lagging behind. Please advise