I'm going to continue Houseplant Month with a contrarian statement. Think about it: there's no such thing as a houseplant. No plant evolved to grow inside of a building, contained within a manufactured pot filled with manufactured "potting soil." Most of what we call "houseplants" originated from the understory of the tropical rainforest, where they receive filtered sunlight through the tree canopy. For these plants to truly thrive in your home, you have to recreate the year-round warmth and humidity of Costa Rica on your windowsill. It's not an easy feat, which is why you've never seen the peace lily at your dentist's office in bloom.
I previously discussed the light needs of common houseplants here. Knowing that plants need light, I keep all of my houseplants clustered in my biggest South-facing window. I also take most of them outside in the summer, taking care to slowly acclimate them to brighter light.
This isn't to say that you can't keep houseplants in less than ideal conditions. Houseplants that perform best in low light have dark green leaves, indicating a dense concentration of chlorophyll. Plants with variegated leaves don't have chlorophyll in the non-green sections of the leaves, so they require brighter light to make up for it. Likewise, plants with red or purple leaves (due to the pigment anthocyanin) also require brighter light due to less chlorophyll.
The houseplants I recommend for beginners are tolerant of low light (though medium light is typically preferred) and are forgiving of neglect. The frequency with which they need to be watered often depends on how much light they receive. A plant in brighter light will use more water via photosynthesis than a plant in lower light. For this very reason, insufficient light and over-watering are the two biggest killers of houseplants, as they often go hand-in-hand. I will discuss watering in greater detail in next week's post.
Best small plants for your desk or bookshelf (click to enlarge images):
Left to right: golden pothos*, heart-leaf philodendron, lucky bamboo
(*beware: hyped-up health claims from misunderstood/misinterpreted science are about to get wackier than ever)
Best mid-sized plants for a plant stand or end table:
Left to right: ZZ plant, 'Emerald Beauty' Chinese evergreen, parlor palm
Best tall plants for floor placement:
Left to right: white bird of paradise, 'Solid Green' snake plant, 'Janet Craig Compacta' dragon tree
Photo sources: Hortology, Costa Farms