Palm trees are a distinctive and potentially wonderful indoor plant. Mature palms often adorn public spaces and foyers, adding an elegant and distinctly tropical air to the decor. At the same time, very small, immature palms are sometimes used as desktop plants, kept in tiny containers.
When it comes to palm trees, it's tempting to think of them as purely tropical plants—give them loads of sun and loads of water, and they'll be fine. While this is certainly true for some variety of palm trees, it's not that easy to generalize across a group of plants that includes thousands of species. Some palms are desert palms and will easily drown with too much water. Still others are understory plants that actually prefer shade and a moister, darker environment.
Likewise, I've heard many people claim that palms don't need to be fertilized, or at least they don't need much. This isn't really true. A palm might cling onto life without regular fertilizer, but if you want healthy palms, you have to feed them. This is true indoors, just as it's true in tropical and subtropical gardens.
Lastly, there is the issue of size. Many of the most common palm trees grown inside, such as the kentia palm, want to become trees. You can slow a palm down by keeping it slightly pot-bound—don't repot every year, and it won't grow as large as quickly. But if you're taking good care of your palm, depending on the species, there is a possibility you'll end up with fronds brushing your ceiling after a few years.
If this happens, I say enjoy it while you can ... because you can never top-trim a palm tree. All palms grow from the central tip. If you cut off the growing tip, the plant will die. So if you really know what you're doing, and you end up with a nearly mature palm bursting from your house, congratulations and maybe it's time to see if a nearby hotel is looking for a wonderful interior specimen plant.
Palm Growing: The Basics
Like all plants, palms need the right balance of moisture, light, fertilizer and warmth to thrive. This varies among the different kinds of palms, so if you're unsure about your specific palm, look up its unique growing conditions. However, here are some of the fundamentals:
- Few palms will thrive in colder temperatures, and some, like the coconut palm, can't tolerate any cold at all. The more cold hardy palms include the parlor and kentia palms, which partly explains why these are the most popular indoor palms. These palms prefer nights down to 50ºF.
- Most palms are much more tolerant of shade than you might think. Again, the parlor and kentia palms prefer partial shade and will suffer in direct sun. Others, including the pygmy date and Washingtonia palm can tolerate much more light.
- Only repot when the palm is completely pot bound. Palms often have shallow root systems, and they don't appreciate being disturbed. Also, infrequent repotting slows the growth rate of palms that might rapidly outgrow your room.
- Good drainage is essential. Just because palms live in warm, sometimes tropical regions, does not mean they are water plants. In fact, many palms grow best in slightly sandy soil with perfect drainage. Never let a palm's root ball sit in water.
- Feed your palm regularly during the growing season. If possible, use a palm fertilizer, which will contain all the micronutrients and extra potassium and manganese. Potassium deficiency is especially common in palms—it shows up in yellowing or brownish fronds.
- Trim your palm carefully. The temptation is hard to resist, but many species of palms draw nutrients from old fronds long after they've begun to yellow or even brown. It's a very common mistake to overprune palm trees, which weakens the overall plant and robs it of valuable nutrients. In general, remove fully browned leaves and never cut your palm down to just one or two new fronds.
How to best display your palm depends on its size and location. They are perfect as corner-specimen plants or foyer plants. Likewise, palms do very well in groups, with smaller potted plants clustered at their base. Wherever you put your palm, try to avoid too much traffic brushing against or pulling on the fronds—this will weaken the plant and possibly kill that frond.
Finally, don't expect your palm to flower indoors. Many of the common species won't live long enough to flower or reach mature size. Remember, some of these are full-fledged trees in the wild. Others just won't bloom indoors. But don't worry—the lack of flowers is more than offset by the plant itself.