If the Zamioculca gets a spot in the light semi-shade, good substrate with a few nutrients and occasionally a little water (when the soil surface feels dry), it will develop lush, very decorative green in no time at all. This just seems to attract small children and animals. We clarify whether the lucky feather is poisonous.
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Maximum easy-care Zamie
If it grows too fast, it can be transplanted into the next larger pot. By carefully pruning the roots that will soon be growing out of the pot, you can stop the growth of the Zamie. If a Zamioculcas has to be in the shade, it will just grow slower and darken. If it does not get water for a long time, in extreme cases a shoot can dry up to the thickened base (the water reservoir), but it will soon sprout again without damage to the plant (in its homeland the Zamie always grows like this).
However, there seems to be a drop of bitterness, and it affects e.g. B. Parents of small children and pet owners who can actually really use maximum easy-care Zamien. Articles about the care of the almost needless miracle plant often warn about the poison of the Zamioculcas. In 2007, for example, one of the best-known national daily newspapers put the Zamie in a row with the most poisonous plants in Germany under the headline “Poisonous plants in the garden threaten small children”. What she didn’t deserve. From a normal yew tree, 100 g of needles can kill a person or a horse, 100 g of Zamioculcas leaves “cannot” do that.
Well, the Zamie was still fairly new to us. Today the data situation is much better. The problem with the poison in the Zamioculcas zamiifolia can be presented in more detail and in a more differentiated manner.
Zamioculcas zamiifolia: toxicity to humans
The leaves and roots of the Zamie contain oxalic acid, initially in the stable, insoluble form of calcium oxalate:
1. Calcium oxalate
Calcium oxalate is not a pleasant substance, it is classified as an “irritant” in EU hazardous substances legislation. The mini-crystals scratch the skin and mucous membranes, in the case of sensitive skin right down to the area of inflammation. But as long as the calcium oxalate molecules stay connected in a crystal, not much else happens even if you eat a few Zamioculcas leaves. Then the calcium oxalate crystals may irritate the mucous membranes of the throat, esophagus and intestines. However, they are otherwise excreted unchanged from the intestine. Calcium oxalate only decomposes at temperatures that would long before cause the death of the entire affected organism.
If a person ingests a large number of calcium oxalate crystals, the urine becomes oversaturated with this salt, which is difficult to excrete anyway. Then the crystals z. B. “deposited” (stored) in the kidneys, which can eventually lead to the formation of kidney stones. Large amounts of calcium oxalate crystals that are difficult for the body to process can also damage cells in the vessels and vessel walls and disrupt the electrolyte and urea metabolism.
Only: Zamien are usually not eaten. That’s why most of the time when you read about calcium oxalate, it’s not about indoor plants, but about fruits and vegetables containing oxalic acid. If not ingested, calcium oxalate crystals are no more irritating than the outer skin. However, at first it sounds as if the defense mechanisms of the Zamioculcas zamiifolia show some mastery in this respect as well:
2. Firing Cells
The Zamioculcas not only armed itself with calcium oxalate crystals, but also developed ideas on how best to disperse these crystals in the predator. These calcium oxalate crystals are located in so-called shooting cells (idioblasts). So the Zamioculcas shoots “poison arrows through the area”.
Oxalate crystals in plants can take a variety of forms. In the Zamie they are in the form of raphides, needle-shaped calcium oxalate crystals with a special mechanism of action. If the shooting cells z. B. are opened when biting the plant, they penetrate like a projectile in the mouth and throat. The calcium oxalate crystals are thus actively secreted by the plant; not only when biting, but with every injury to the plant skin. However, it is about very small projectiles that can only be seen really well under a microscope.
There are no reports of burning skin that can clearly be traced back to the care of the zamies. Rather the opposite: A chemistry professor reports on his website about his hobby Zamioculcas that despite close contact with the plant (cutting off leaves, tying them up, cleaning, stroking them, wiping plant juice from injuries), he and his wife never heard anything about poison or irritation would have noticed. It is known from other plants with calcium oxalate crystals (such as Dieffenbachia, for example) that skin contact with the plant sap can cause unpleasant tingling and stinging.
As a precaution, people with sensitive skin should wear gloves when tending to the plants. If there is tingling after contact with the zamie, the oxalate needles are usually easy to see under polarized light (e.g. LCD monitor) and can be removed with patience, a magnifying glass or tweezers. They can also be dissolved in acid, but this requires just as much patience when hand bathing with skin-friendly lemon juice dilution (rinse off, carefully pat dry, repeat if necessary).
Calcium oxalate crystals are annoying but largely harmless. There is one exception: If a Zamioculcas lover manages to rub the plant sap into their eyes, the information center against poisoning at the University Clinic Bonn recommends rapid and extensive rinsing and, if symptoms persist, visiting an ophthalmologist.
3. Oxalic acid
Calcium oxalate crystals aren’t the only thing Zamioculcas zamiifolia has to offer. Because raphides are a very special form of calcium oxalate crystals: they have tiny grooves through which free oxalic acids can also get into irritated skin.
Free oxalic acid is not so fun, but “harmful to health” according to EU legislation on hazardous substances. But still not “toxic” (that would be sort of the next step up from irritant and harmful, though it’s not quite that simple); which is why the Zamioculcas does not appear in the official list of Germany’s poisonous plants, nor in the constantly updated Wikipedia list of poisonous plants.
A little oxalic acid is bound with calcium in the body. A lot of oxalic acid can deplete the body’s calcium and magnesium stores (with negative consequences not only for the bones). However, caring for a Zamioculcas allows very little oxalic acid to enter the body via crystal needle mini-wounds. The “little oxalic acid” that is meant gets into the body through consumption and not through plant care; It usually only gets interesting from several hundred grams. Which the average German citizen clearly prefers to eat in the form of amaranth, spinach or carrots than to nibble off the stalks of his favorite houseplant.
Oxalic acid in the body is bound by calcium to form the insoluble form of calcium oxalate that we are familiar with, so that it can be “disposed of” in the urine. Even when ingested, the content of valuable nutrients usually predominates. People who eat only freshly harvested amaranth seeds and spinach salad as part of an “Aztec diet” may have problems with oxalic acid in their diet; people with a varied diet actually only in connection with various diseases. Only when the corresponding body is not healthy and sufficiently supplied with calcium AND too much oxalic acid is bound or too many calcium oxalate crystals have to be disposed of does consumed oxalic acid cause damage, at first small and imperceptible, after a long time also large ones that can really hurt.
By the way: Regardless of whether you have small children in the uncritical trial phase, dogs on a long-term diet or freshly inspired vegetarians who are keen to experiment in the household, they will all only nibble briefly on the Zamie once at most. All parts of the plant taste pretty nasty, bitter and burn in the mouth.
Before discussing whether the Zamioculcas is dangerous for pets, one more pleasant side deserves mention:
Clean Air
So the chance of becoming poisoned by a zamie is quite small – while the chance of becoming a little healthier by a zamie is quite large: the zamie processes toxins from the air in its plant metabolism; this has been clearly demonstrated in several scientific research projects. Zamioculcas zamiifolia filters benzene, toluene, ethylbenzene and xylene from the air.
Zamioculcas as a threat to pets?
According to the University of Zurich, the Zamioculcas zamiifolia is highly toxic to the animals that live with us. What “highly toxic” means is explained on the page as follows: Poisoning symptoms after ingestion of small amounts of plants. The source doesn’t tell us which animals the zamie is poisonous to.
According to other sources, the Zamioculas is poisonous to dogs and cats, birds and rodents (such as chinchillas, hamsters and rabbits). The possible symptoms are described in a similar way to those of human poisoning.
Even if strange docu-soaps sometimes make you doubt it, most German pet owners do not feed their animals any houseplants. If a hamster is so distraught that it develops a compulsion to tackle bitter, burning plants, it’s likely to die of lack of interest in life soon enough.
What about the domestic pig, the miniature horse on the sofa – and the real pig and horse in the stable? This explains why www.vetpharm.uzh.ch does not list which animals are affected. This is a website from the Institute of Veterinary Pharmacology and Toxicology Zurich, which requires a certain basic knowledge. For example, farmers and horse owners know not to feed pigs and horses indoor plants. It is also assumed that every animal owner knows that every pet mammal is usually at least as sensitive to the same plants that are poisonous to humans as the owner.
They further assume that every animal owner knows that animals can also be much more sensitive than humans to all sorts of things. It could therefore be expressed more simply the other way around. For every animal that we usually keep as a pet, it is clear that it should not come into close contact with yew trees, thujas, cherry laurels or indoor plants. In addition, there are enough empirical values for the poisonous plants that pets can usually come into contact with. If the animal owner gets an exotic animal, he must inform himself about the whole keeping and not only about potential poisons. He needs a specialized vet anyway. If in doubt, he can then ask him about the toxicity of a Zamioculcas for this animal.
Zamien as a cancer trigger or promoter?
The web is big and zeros and ones are patient, so it’s no surprise that news about cancer-causing ingredients in Zamioculcas zamiifolia is also circulating on the internet. On ResearchGate, an international platform for researchers, Beng-Jin Chee from the Forest Research Institute Malaysia (FRIM, Forest Research Institute Malaysia) asked if there were any reliable research publications on the toxicity or carcinogenic effects of Zamioculcas zamiifolia. The answer came from Arvind Singh of Banaras Hindu University (located in Varanasi, Uttar Pradesh state, India), who praises the ornamental plant’s air-purifying properties, mentions calcium oxalate crystals, and otherwise notes that there is no scientific evidence of zamie’s cancer-inducing effects.
Maybe someone just wanted to hurt their competitor or didn’t begrudge their neighbor their beautiful potted plant; in the case of alleged effects of any plants, however, it is always advisable to ask for reliable evidence.
Conclusion
Zamioculcas zamiifolia poses a certain risk potential for the skin of sensitive people and possibly a much greater risk for pets. However, no pet in good nutritional and employment condition will willingly ingest enough Zamioculcas leaves to cause harm.
