The redder the better, especially if they are poinsettias.

The Aztecs cultivated poinsettias near present day Cuernavaca. Today there are pink, white, orange, and even multi-colored poinsettias, all hybridized to complement any holiday décor.

The designer colors are beautiful, but many still prefer the traditional holiday red.

To keep the bright red bracts of your potted poinsettias at their peak, place them in bright light, maintain approximately 50 percent humidity, and don't over-water them.

Need to freshen up your home or office?

Let a plant do the dirty work. For instance, a spider plant gets rid of formaldehyde fumes from your new carpeting, thanks to microorganisms living in potting soil that use airborne toxins as a source of food. Plant roots absorb the waste produced by those microorganisms and release cleaner air in your home.

"Some plants work better because their root systems prefer pollutants and use them as food faster than others," says Bill Wolverton, Ph.D., who runs an environmental research firm in Picayune, MS.

Estimating the number of plants to best do the job isn't easy and he advises that you overestimate the number rather than underestimate it. However, it's easy to figure out the types of plants to use.

Here are 11 of the best — and easiest to maintain — household plants to hold down pollution levels in your home or office for better breathing and energy.

1. bamboo or areca palm
2. Boston fern (or any fern)
3. chrysanthemum
4. dracaena
5. English ivy (or any ivy)
6. gerbera daisy
7. golden pothos
8. peace lily
9. philodendron
10. snake plant
11. spider plant