All About The Kentia Palm

Kentia Palm

To me, there is no more attractive and elegant indoor palm tree than the kentia palm (Howea forsteriana).

Apparently I am not alone, because it is a perennial favorite among collectors and casual indoor gardeners alike and is touted as the most popular decorative palm in the world. Nevertheless, despite this fame, it is often misunderstood. Here we take a closer look at the kentia palm, and hopefully give you some growing tips along the way to keep it thriving in your care.

Origin & Brief History of The Kentia Palm

To really understand how to care for a plant species, it’s a good idea to know where it comes from. And in the case of the kentia palm, it’s a particularly interesting story.

Home of the kentia palm

Image by NASA Johnson Space Center. [Public domain], via Wikimedia Commons

The kentia palm (or “thatch” palm, a name originating from the settlers who lined their roofs with their fronds) is endemic to a place called Lord Howe Island, which is a boomerang-shaped land mass situated off the southeast coast of Australia, in between the Australian continent and New Zealand. This is a little spec of an island, hard to find on a map, even when you know where to look! In fact, Lord Howe is just a mere 5.6 square miles in area and only a half of a mile in width throughout much of it’s length. A lilipad in the ocean.

However, what it lacks in size it more than makes for in terms of beauty and species richness. The island remains mostly undeveloped along the larger southern half, which is dominated by virgin forest that clings to two rugged mountains rising nearly 2900 feet up from the ocean. Due to the particular assemblage of native plants and animals found there and nowhere else (nearly 44% of all vascular plants are endemic, including the kentia palm), Lord Howe easily earned the recognition of UNESCO as a World Heritage Site for the amazing amount of biodiversity it contains. A fitting paradise for the kentia palm.

Kentia palm native habitat

Kentia palms growing on Lord Howe at Neds Beach.
Black Diamond Images – CC BY 2.0

Kentia palm native habitat

Kentia palm in native habitat on Lord Howe.
Black Diamond Images – CC BY 2.0

Lord Howe has a cool, subtropical climate with an average low of 56F in August and average high of 78F in February. The island receives a total of approximately 59 inches of rainfall per year and humidity hovers between 60-70% year-round. There is no wet/dry season, with an average of 4-6 inches of rain falling each month. While helpful, keep in that these data come from the flatter, lower northern end of the island and therefore likely underestimate both the average low temperatures and rainfall experienced along the mistier reaches of the mountainous south.

The commercial exportation of kentia palm seed started in the 1880s, soon after it became apparent to first-world nations that this species was among the most suitable and attractive palms for indoor culture.

The demand for material quickly increased and by 1906 the Lord Howe Island Kentia Palm Nursery was born. Only seed was exported until 1980, after which time seedlings also became available. Satisfying the demand for kentia palms is still a vital part of Lord Howe’s economy to this day.

Growing The Kentia Palm

Howea forsteriana in the wild or grown outdoors can reach over 30 feet tall and can develop fronds up to 10 feet long. The mature plant looks a lot like a coconut palm and is single-stemmed. In good conditions they will often produce pendant clusters of small orange to reddish-black fruit that hang like beads on a string.

Kentia palm ready for sale

A young kentia palm ready for sale.
Forest & Kim Starr -CC BY 2.0

The kentia palm is often grown outdoors as a patio specimen or in the ground in full sun as a landscape/street tree in frost-free zones worldwide. They are quick to tolerate shade in such cases, but they look best and become larger in full sun. For example, in the U.S., they are frequently grown outside in coastal southern California where temperatures are moderate. However, even in the best of circumstances, they often have some difficulty transitioning from part shade to full sun, and it may take a few growing seasons for a kentia palm to really take advantage of sustained direct light. Full sun should be completely avoided in very hot, arid regions at all costs.

While mature plants outdoors may tolerate full sun in cooler regions, as a general rule indoor and smaller container plants should be kept in bright indirect light only. Indeed, the kentia palm will thrive indoors in bright indirect light from an east or west-facing window. Well-filtered light from a south-facing window or a bright location near such a window is also fine. Indirect light from a north-facing window may keep a plant alive, but is just too dim to support significant growth in my experience.

When picking a suitable location, besides ensuring bright indirect light, remember that this plant’s fronds do tend to spread quite a bit (one of the reasons why they are so elegant), so put them somewhere where they can stretch. While these are considered slow growers, I find that in good lighting they will regularly produce fronds that can get quite large, even when grown in small pots. Their overall height indoors is normally limited by the size of the window(s) they are getting light from, but palms of over 8 feet in height are common.

Kentia palm habitat in the south of Lord Howe

H. forsteriana growing in cool, pristine forest.
John Game – CC BY-NC-SA 2.0

This species if very comfortable in average household temperatures, and the only caution is to avoid heat, typically from direct sunlight. Fortunately, H. forsteriana does not require the 60-70% humidity of Lord Howe in the home, but it is a good idea to mist this plant frequently as it does help keep it free from dust and makes the plant a bit less vulnerable to spider mites and mealybugs in my experience.

The kentia palm is not terribly picky about soils, but the soil should be quick-draining and preferably rich in organic matter. It should be watered like most houseplants; i.e., using the finger-stick method and allowing the surface soils to dry slightly between waterings. Do not leave this species in constantly wet or waterlogged soil as root rot can develop very quickly.

Indoor-grown plants outgrow their pots very slowly, and it’s best to err on the side of a smaller pot rather than quickly moving them up to a bigger one. If in doubt, pull the plant from the pot and check the root ball – has it nearly completely conformed to and filled the pot…and/or are roots starting to force their way into the drainage holes? If so, then repotting in a slightly large pot (no more than 20-30% bigger than the original) is warranted.

A common issue observed with kentia palms indoors is that they are very prone to leaf-tip burn. This is usually due to hard-water minerals/salts normally present in tap water. These salts/minerals are relatively dilute off the tap but in time accumulate in the leaf tips because that’s where transpiration (water loss) is highest, and because water evaporates but these dissolved substances do not and continue to increase over time. Slightly burned tips (affecting less than an inch of the tips) are not much of a problem and can be cut off if unsightly. To help prevent a mild case of burn, make sure that whenever you water this plant, do so thoroughly and really let the water flow out of the bottom of the pot (and ensure proper drainage by discarding it, rather than letting it wick back up into the pot from the tray).

kentia palm disease

Damage caused by Cylindrocladium infection.
Scot Nelson under CC BY-SA 2.0

More extensive burn suggests more elevated levels of salts/minerals that can profoundly alter soil chemistry as well as causing localized leaf necrosis. For example, high levels of calcium bicarbonate in hard water sources over time will result in a very alkaline soil; and very alkaline soils often make fertilizers and certain trace elements (e.g., iron) inaccessible to plants. Consequently, if you see significant tip-burn and the plant seems to look weak (and/or grow pale or yellowish, a classic sign of possible chlorosis), I’d suggest you water this species with reverse osmosis water (the type from large machines outside of some grocery/convenience stores – don’t trust your refrigerator filter or most tap filters that don’t remove minerals) or distilled water.Depending on how hard your water is, it may not necessary to water with RO or distilled each time, but you can at least do so periodically to “purge” the soil now and again.

As far as pests go, the most likely suspects encountered indoors are mealybugs, spidermites and scale; whereas outdoors there are more concerns, including various fungal infections, such as “black rot” (Cylindrocladium sp.) and “pink rot” (Nalanthamala vermoeseni), and more mysterious pathogens like “Leaning Crown Disease.”

Finally, it is a good idea to fertilize your kentia palm regularly using a high quality indoor plant or palm food. Fertilize throughout the year (especially if regularly watering with distilled or reverse osmosis, which tends to leach just about everything from the soil) but adjust strength based on need. In general, higher temperatures and higher light means a greater need. For example, an indoor plant grown in a relatively dim corner in winter may need at best 1/2 the manufacturer’s recommended fertilizer dose; whereas a vigorous plant in bright light during the summertime may benefit from the full dose.

The Kentia Palm’s Close Cousin – The “Belmore Sentry” Palm.

belmore sentry palm- cousin of the kentia palm

Note the downward fronds of H. belmoreana.
tanetahi under CC BY 2.0

Although not nearly as popular as the kentia palm, its closely-related congener, the Belmore sentry  or “curly” palm (Howea belmoreana), is also sometimes available.

This species too hails only from Lord Howe, and is in all husbandry respects virtually identical to the kentia palm. However, H. belmoreana stays smaller (around 20 feet) and has a more compact crown with fronds that tend to curved downward, thereby giving it a more “curly”-shaped look.

Featured (top) photo credit: “Howea forsteriana” by László Majercsik under CC BY-NC-SA 2.0

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