How long can a houseplant be legitimately expected to live?
You probably expect yours to survive at least 2 or 3 years, even more. In fact, when you purchase a houseplant, you probably simply think it will live forever. But did you know that the vendor considers the natural life expectancy of a houseplant to be… 8 weeks? And only 4 weeks in the case of a flowering plant? Decidedly, garden centers and florists are not very confident in the ability of their customers to care for houseplants!
Sadly, this belief – that 8 weeks is the normal lifespan of a foliage plant and 4 weeks, that of a flowering one – can have a negative influence on the success you actually do have with the plant, at least in the medium and long term. That’s because the information the seller gives about caring for your plant is based on his acceptance of a very limited lifespan. Here’s an example:
The label on the rubber plants (Ficus elastica) sold in my local garden center bear a symbol indicating that they can be grown in low light. How reassuring! In most homes, sun is at a premium. How nice to know that I can stick my new rubber plant in a dark corner and expect it to thrive.
However, the rubber plant is not a low-light plant, not if you want it to live a long life. Rather, it needs good light at all times and in fact prefers a few hours of full sun daily. But it can tolerate low light for a lengthy period, well over 8 weeks, before it starts to deteriorate, so the supplier feels justified in sticking a “low light plant” symbol on the label.
Thus the poor rubber plant stuck in that dark corner will hold on, though it won’t thrive, for months, sometimes even up to half a year… but when it finally does use up the last of its stored energy, it will die. Of course, the supplier feels no guilt over this – hey, the plant lasted more than 8 weeks! – but the plant’s new owner is disappointed and probably feels guilty. Where did he go wrong? This is even sadder in that the rubber plant is particularly long-lived: properly maintained, it can thrive in the average home for decades… but not in low light.
Misinformation and Inappropriate Practices
It’s not just a matter of lighting, of course, although you’d be surprised at how few “low light plants” really can live for long periods in the low light. Here are some other bits of misinformation that can be conveyed by suppliers who see houseplants as perishables rather than living organisms:
- If a given plant can tolerate dry air temporarily, the label will likely claim it is adapted to dry air, even if it needs good humidity for its long term survival.
- Carnivorous plants require rainwater or distilled water for their long term survival and will only tolerate tap water for short periods, but the label is unlikely to inform you of this inconvenient truth.
- You may be told to you can water an orchid by placing ice cubes on its roots… but the orchid in question is a tropical plant and such a treatment will eventually kill it… but not within 8 weeks.
- Cactus are often sold in terrariums, yet the high humidity that reigns in a terrarium will eventually cause them to rot… but only 4, 5 or 6 months down the line.
- You may be told that your air plant (Tillandsia) gets all the moisture it needs from the surrounding air and never needs watering… causing a slow but fatal dehydration.
Where to Find the Correct Information
The garden centers that sell houseplants don’t make the labels with misleading information; they just sell the plants as they are shipped to them, misleading label and all. So skip the label and instead ask questions of a real person! There is almost always a trustworthy, knowledgeable gardener on staff who can really give you the correct growing information about the plant you’re interested in.
Websites that claim to have answers to everything are horrible places to find information on houseplants: they generally just parrot the misinformation the original supplier gave. The same goes for any website that seems to see houseplants as elements of interior design. However, there are plenty of good houseplant websites, especially those associated with universities or that are run by people who are obviously plant nuts. You can find trustworthy information there.
And most houseplant books are written by people who are truly passionate about plants and have considerable experience with them, so they also supply excellent information on houseplants. I’ve written many books on houseplants myself and confess to being a plant nut: maybe you can find one of mine?
The Real Life Expectancy of Houseplants
How long can a houseplant really live?
Obviously, there are plants that are naturally short-lived under indoor conditions and you should indeed use them as the seller intended: as short-term decorations. I call them “gift plants” and inevitably they are plants raised in cool greenhouses under high humidity: no one legitimately considers them to be true houseplants. This group includes cinerarias, calceolarias, lilies, hydrangeas, spring bulbs, etc.
Other than these few ephemerals, there is in fact almost no limit to how long most “true houseplants” can live if you give them the conditions they require: good light, good humidity, appropriate watering, etc. People often write me about houseplants they’ve been growing for 20 years or longer and are still thriving.
The oldest indoor plant in the world is said to be an Eastern Cape giant cycad (Encephalartos altensteinii). It has been growing in the greenhouses of Kew Gardens since 1775 and is still in perfect health. Ten to one the original vendor’s label didn’t recommend it as a low light plant!