Sweetheart Philodendron has dark green, shiny, heart-shaped leaves and looks great as a table or hanging plant. Heartleaf Philodendrons are some of the most popular indoor plants we use in homes and offices because they thrive on neglect and are almost impossible to kill. Another great plus, philodendron plants remove air-born toxins such as formaldehyde from the air. NASA lists a Heartleaf Philodendron as a clean air plant that removes formaldehyde, a chemical found in insulation, floor coverings, cleaning agents, pressed wood, and even paper towels, from the air.