Most palms are relatively safe to grow, but some have their hazards.
When most people think of palms, they think of a ferny-like tropical tree or shrub, sort of like what Xena Princess Warrior would experience running through on her show filmed in New Zealand, or the soft, willowy foliage the troops of some jungle war movie might be slinking through.Indeed, many people grow palms for their luxurious tropical foliage.However, a lot of palms are not so ‘user-friendly' and can be dangerous in several ways.
Many palms, particularly the ones that grow well for me in California, are equipped with all sorts of sharp, annoying spines, thorns, teeth or simply very sharp leaves.These palms are not only unsafe to go blundering into, but can be risky pruning or planting.
Examples of palms with spines are many, though most seriously spiny palms are truly tropical in nature and I do not have any of these in my yard.Some of these palms are primarily spiny when young, possibly to give them some defense against predation while still small enough to be considered food, and losing the spines at maturity when, as trees, are less interesting to herbivores.However, other palms are so spiny, even in adulthood as to have spines on nearly every surface and structure.These palms tend to have the most vicious spines and should really be avoided, or planted far from walkways.
Zombia antillarum has a highly ornamental spiny woven pattern on its multiple trunks (lower photo above). These spines are very sharp and thick
Some species are simply spiny all over... above is a leaf and spathe from Acrocomia aculeata that is completely covered in spines; right are fruits of Astrocaryum alatum that are spiny- this entire plant, including the leaflets, have deadly sharp spines
Some of the most beautiful but dangerous palms in the tropics are of the genus Pigafetta (left photo), as they not only have very long, very sharp spines arming their leaves (see fallen leaf base on right), but they grow quickly to sixty feet tall or more, and then drop these deadly, spiny leaves, impaling whoever happens to be unlucky enough to be below at the time. These leaves can weigh over thirty pounds, too.
Many palms have teeth on the petioles (the 'branch' that holds the leaf), and some of these teeth can really take a bite out of you if you are not careful.The common Washingtonia (Mexican Fan Palm) is well known for being a tricky palm to not only trim safely, but the falling leaves tend to get hung on ones clothing or drop onto others below causing serious damage.
Washingtonia robusta leave blades showing sharp, hooked, brown petiolar teeth- these are almost like razor blades
Chamaerops humilis is another common palm with killer teeth along the petioles. Trimmed palms look great and are true landscape specimens (right)... to trim the palm on the left to get to the palm on the right can be an extremely dangerous and painful undertaking
Chamaerops humilis petioles (left); other species with vicious teeth: Copernica alba (middle) and Corypha utan (right)
most Copernicia have sharp teeth- Copernicia baileyana (left) as do most Livistona sp. (Livistona saribus in right photo)
Still other palms have modified leaves along the base of the petioles that can be extremely sharp and long making pruning these palms a truly hazardous experience. Phoenix palms are a prime example of such dangerous plants.
mature and immature Phoenix canariensis palms showing spines on leaf bases. Photo on right shows that I have tried to cut the sharp tips off most of these spines as these are still at a level where these could easily impale me as I walk by, or could even jab me in the eye.
fallen Phoenix canariensis palm leaf in a succulent garden makes a treacherous obstacle thanks to the modified leaf spines (left); right shows another species of Phoenix: Phoenix theophrasti, probably the king of the spines in the Phoenix genus
Calamus caryotoides, like many Rattan Palms, have whips and cirri that are modified leaflets used for climbing (these are climbing palms and climb up other vegetation in the jungle). These cirri are long, thin and heavily armed with extremely sharp hooks that tend to grab onto what ever walks by too close. It is an attractive palm, but a really dangerous one to plant anywhere near a pathway.
Other palms have toothless petioles, but that does not always mean there is nothing dangerous about them.The petiolar blades themselves can be sharp as knives pn some fan palms and one still needs to be cautious when trimming these species, or particularly if one is foolish enough to try to climb one.
Bismarckia (left) and Borrasodendron sp. (right) have knife-like blades
Above is a Sabal mauritiiformis petiole that I personally have been lacerated by
And even the leaves themselves can be lethal on some species- with tips so sharp who needs teeth or spines?
So if being punctured or lacerated is not enough of a danger, other palms can be dangerous thanks to gravity.Some of the larger species can drop leaves that weigh over fifty pounds each.A mature Royal Palm (Roystonea species) can let loose a 60 pound frond that can not only deliver a nasty blow, but do a great deal of serious property damage to whatever it crushes below.Even the common King Palm can unleash a twenty pound frond now and then that can at least give on a respectable bruise.
Royal in Southern California in private garden (left). Since this photo was taken, the owner sold the palm and had it moved since the fronds had damaged multiple vehicles parked below. Left shows a row of Roystonea oleraceas along a mall parking area in Hawaii, but no parking allowed near these palms
Royal and King palms in zoo (left) far from where they falling leaves can knock someone in the head... hope the flamingos are paying attention. Right shows another very tall species with extremely heavy leaves: Ceroxylon ventricosum. Fortunately these leaves tend to fall straight down, with the leaf base hugging the trunk the whole way down, so this one is a bit less hazardous to have along a sidewalk or driveway
Coconut palms are well known for their heavy, solid fruits being dangerous to pedestrians and automobiles below, and many tropical inhabitants have been badly injured by these heavy, coconut-milk-filled bombs.Borassus and Loedicia species have respectable gravity-propelled weaponry as well.
Coconuts are loading with dangerous weapons (see left); Right shows fallen coconut seeds that have fallen on a lawn (photo Thaumturgist)
If you live in the Seychelle Islands, walking below the palms can be even more hazardous as that is the home of Lodoicea, the Double Coconut, aptly named due to the massive seed these palms make. Photo on right is of a naked seed weighing over fifty pounds before it was hollowed out. This is a rare and hard to grow species and each seed can run as much as $450 US.
Borassus flabilifer fruits make potential lethal bombs as well, weighing about five pounds each (left); right is Borassus flabilifer in fruit
And if you are not convinced that a falling palm leaf or seed can injure you, what of a falling palm?Though in many cases palms are much less likely to come down in high winds than most other trees, some palms can not only be blown over, but seem to simply fall over for no reason, even on a calm day.Caryotas, for whatever reason, tend to do this, and though not commonly grown in yards throughout the world, still manage to inflict major property damage to those that do favor these species, thanks to their incredibly solid woody trunks and top-heavy leafy crowns.
Queen palm fallen on a parked car (left)- planted in too wet soil too shallowly; right shows a Caryota gigas getting tall enough to do some serious damage should it just decide to fall over
Though palms, in general, are among some of the least toxic of the tropical foliage plants in cultivation, some have toxic fruits.Caryotas and Arenga species have oxylates in the fleshy coating surrounding their seeds that not only are toxic, but can cause physical pain if handled carelessly, as the oxylates cause a stinging sensation.
Arenga engleri fruit (left) and Arenga pinnata fruit on the ground (right). Even walking on this fruit with bare feet can result in a toxic dermatitis
Arenga australisica fruit (left) and Caryota mitis fruit (right). Both a extremely irritating if eaten or even handled roughly
Areca catechu, aka Betel Nut Palm, has fruits commonly munched on by local residents in and near Thailand. This fruit is moderately toxic in that it is a mild stimulant but can have an addictive property. Sucking on Betel Nuts can damage teeth and gums over time, not to mention permanently staining these tissues orange.
Note: Cycas species (eg 'Sago Palms') are NOT palms, but are cycads. They are indeed extremely poisonous, but I have not included cycads in this discussion because they are not palms, despite their common name)
And though most are not poisonous, some palms drop vast amounts of seeds that can create other minor hazards, from a rotting, slippery mush, or a ball-bearing-covered sidewalk, to potential indigestible foreign bodies in pets and children, who sometimes eat the fruits and carelessly swallow the hard seeds inside whole.I have personally removed several Queen palm seed intestinal blockages from pets over the years.
Butia capitata (left) and Dypsis decaryi (right) fruits on ground make a slippery hazard when they are rotten and gooey
Fruits eaten by pets or children can lead to intestinal blockages as their seeds are often too large to pass through the guts (Wodyetia left). Right fruits are of Butia capitata and are very tasty, so eating them is very tempting
Addtional dangers of palms could include harboring disease-carrying pests. Washingtonia palms are well known for being a large apartment complex for all sorts of vermin from rats and mice, spiders and scorpions and all sorts of birds (pigeons and owls most commonly, though owls are rarely considered pests).
Washingtonia robustas with full skirts probably full fo all sorts of surprises... this is why most publically planted palms are trimmed regularly
Last, but not least is the possible danger of seeing a palm so beautiful one simply drops dead in amazement...
About Geoff Stein
Veterinarian and Exotic Plant Lover... and obsessive, compulsive collector of all oddball tropical and desert plants.