Twelve Christmas or Holiday Plants - Poisonous and Safe
The Joy of Traditional Christmas Plants
Christmas is a fun festival for many people and is often a very meaningful celebration as well. Family or personal traditions are especially popular at this time of year. Bringing special plants into the home and admiring their flowers, fruits or leaves is often one of these traditions.
Unfortunately, several popular Christmas or holiday plants are poisonous for humans and animals. This probably won't be a problem for adults or older children, who aren't likely to eat any part of a toxic plant and are probably prepared to wear gloves if necessary when handling the plant. It may very well be a problem for young children or pets, however. Luckily, there are some non-toxic plants that are an enjoyable addition to a home at Christmas time.
The shiny green leaves and bright red berries of holly are a cheerful and festive sight. I admire wild holly on my walks instead of bringing it home, however.
One potential problem with bringing holly indoors is the fact that the prickles on the leaves can damage the skin, mouth and digestive tract of a child or pet. Since the leaves would be painful to eat, however, they aren't likely to hurt anyone by ingestion.
A more serious concern is the toxin in holly berries. The toxin is present in the rest of the plant too, but it's most concentrated in the berries. The red berries may be especially appealing to young children or pets, who often like to put things into their mouths.
A Squirrel Eating Holly Berries
Theobromine in Holly
The toxin in holly is theobromine, an alkaloid chemical that is also found in cocoa and chocolate and is quite similar in structure to caffeine. Theobromine poisoning can cause gastrointestinal problems (stomach pain, nausea, vomiting and diarrhea) as well as dizziness, a rapid pulse and low blood pressure. The more berries that are eaten, the more likely that sufficient theobromine will be ingested to cause poisoning.
Theobromine is especially dangerous for dogs because their bodies break it down very slowly. This is why chocolate is poisonous for them. Interestingly, although holly berries are toxic for humans, dogs and cats, they are edible for some wildlife.
Kissing underneath a piece of mistletoe is a popular Christmas tradition in some countries. The custom is supposed to bring good luck, especially in marriage.
Mistletoe is an interesting plant. It's an evergreen parasite that grows on the branches of trees and shrubs and inserts projections called haustoria into its host. The haustoria absorb mineral nutrients and water from the host.
A mistletoe plant is classified as a hemiparasite instead of a full parasite because it isn't entirely dependent on its host for survival. It has green leaves and can carry out photosynthesis. Photosynthesis is the process by which plants make their own food from simple nutrients, using light as an energy source.
The word "mistletoe" actually refers to many different species of plants. The specific toxins in a mistletoe and the danger that it presents depend on its identity.
The species that is most commonly associated with Christmas is the European mistletoe, or Viscum album. This plant has paired, oval leaves and yellow-green flowers. In the fall and winter the plant bears clusters of white berries that have a waxy appearance.
The leaves and berries of European mistletoe are poisonous. They contain several chemicals that can cause severe gastrointestinal problems. The website of the Royal Botanic Gardens at Kew states that although "as few as three or four berries" can cause a stomach ache in a child, poisoning is rarely serious in people. However, according to the website, some dogs have died due to European mistletoe poisoning.
North American Mistletoes
In North America the native mistletoes belong to the genus Phoradendron. The species used at Christmas resemble the European mistletoe. Some species are more dangerous than others, but all of them should be treated as potentially harmful if they're brought into a house. They contain a substance called phoratoxin. This can cause nausea, vomiting, stomach pain, diarrhea, blurred vision, a slow heart beat and low blood pressure.
English ivy (Hedera helix) is often used in Christmas decorations. It's a climbing and creeping vine that looks very attractive as it trails out of plant containers. The plant is toxic for humans and pets, however.
Ivy grows in the wild and is also cultivated. It has two kinds of leaves. The vegetative or non-reproductive part of the plant has leaves with pointed lobes and the flowering part has oval leaves. The leaves are usually dark green but may also be green and yellow, which is a popular color combination in cultivated ivy. The flowers are small and yellow-green in color and are borne in clusters. They produce blue-black berries.
Handling English ivy can cause severe contact dermatitis, or skin inflammation, which may be accompanied by blisters. This is the most dangerous aspect of the plant for most people.
Ivy is poisonous when taken internally, although a large amount of plant material needs to be eaten to cause symptoms. These symptoms can be serious and include a burning sensation in the digestive tract, breathing difficulty, gastrointestinal problems, delirium, hallucinations and seizures.
A yew is an evergreen tree or shrub that has needles for leaves and bears colorful red "berries". Yews are conifers, or cone bearers. The berry is actually a structure called an aril that develops from a modified cone scale. Each aril surrounds one seed.
The combination of red arils and green needles make yew look very much like a Christmas plant. It's sometimes used for this purpose. Using the plant in Christmas decorations is a bad idea, however, because it's very poisonous for people, pets, horses and livestock. Interestingly, as is the case for holly berries, some wild animals feed on yew arils without being poisoned.
Yew contains chemicals called taxines which quickly cause an irregular heartbeat after being eaten. The alteration in the heart rate can be life-threatening. Yew poisoning can also cause a headache, dizziness, gastrointestinal problems, breathing difficulties, trembling, convulsions, dilated pupils and a coma.
The Poinsettia Plant
For many people, a poinsettia in the home is a traditional part of Christmas. The plant is native to Central America and was introduced to the United States in 1825 by Joel Roberts Poinsett. Poinsett was the first US minister to Mexico.
The scientific name of the poinsettia is Euphorbia pulcherrima. The plant grows as a shrub or small tree. The red "petals" are actually bracts, which are specialized leaves that surround a flower. The flower of the poinsettia is small and pale in color.
A careful pattern of light and dark periods is necessary to get the normally green bracts of a poinsettia to develop their typical red color. Plant breeders have created plants with a variety of other bract colors, including pink, orange, white and marbled.
Toxicity of Poinsettia
The poinsettia has had a reputation as a very poisonous and potentially deadly plant for some time. Researchers are now saying that poinsettias are not poisonous or only slightly so and that the early assessment of the plant's toxicity was flawed.
Eating part of a poinsettia will probably produce no symptoms at all or at worst produce only mild nausea and perhaps vomiting. A person will probably never get to the nausea and vomiting stage because many leaves have to be ingested to cause any effects. This isn't likely because the leaves taste bad. Contact with the sap of a poinsettia may cause the skin to develop a mild itch, however.
The National Institutes of Health says that poinsettia is "not poisonous" for humans. ASPCA (American Society for Prevention of Cruelty to Animals) says that poinsettia is toxic for dogs and cats, causing stomach upset and occasional vomiting, but also says that the plant is "generally over-rated in toxicity".
Breeding Coleus Plants
Coleus is an attractive and popular plant that often has variegated leaves (those that contain more than one color). Some have a lovely mixture of red and green - the Christmas colors. The colors are arranged in a variety of interesting patterns. Plant breeders are creating lots of new and very appealing varieties of coleus.
Coleus is non-toxic to humans but is toxic to pets. It can cause vomiting and diarrhea in dogs and cats, which may occasionally be bloody. In a home without pets, however, coleus is a beautiful plant to display indoors at Christmas and during the rest of the year either indoors or outdoors.
A Tour of a Christmas Cactus Plant
The Christmas cactus is my favorite holiday plant. Mine bloom in November instead of at Christmas, but the appearance of the colorful flowers always gets me in the Christmas mood.
Christmas cactus is not poisonous for humans, dogs or cats. Since I have both dogs and cats in my family, lack of toxicity is a very important factor in my decision to buy a house plant. The cactus is long-lived and very easy to care for. Mine seem determined to flower near the end of each year, no matter how they've been treated during the rest of the year.
The Christmas cactus belongs to the genus Schlumbergera, which is native to Brazil. It's available with pink, red, purple, orange, yellow or white flowers. The stems are made of flat, leaf-like pads joined to each other in a chain. The stems are green and carry out photosynthesis. The cactus has no leaves.
Cyclamens have beautiful flowers with upright petals that are sometimes twisted. They also have attractive, variegated leaves. The flowers may be pink, red, purple or white and often have a lovely fragrance.
The species of cyclamen that is most often sold by florists is Cyclamen persicum. The word "cyclamen" is used as both the first word in the scientific name and as a common name. Cyclamen persicum normally becomes active during autumn, winter and spring and enters dormancy during the summer. It flowers during late winter or early spring.
Cyclamens develop from a tuber that forms on an underground stem called a rhizome. The plants contain chemicals called triterpenoid saponins, which are toxic. These chemicals are most concentrated in the tubers.
Ingesting tubers may be more problematic than eating the leaves or flowers, depending on the amount that's ingested. The tubers taste bad, however, which reduces the chance that they will be eaten. In addition, they are hidden in the soil of a pot. If a child or pet knocks the pot down and breaks it, or if a pet likes to dig in the soil of a plant pot, it will be easier to get to the tubers, however.
Cyclamen poisoning may cause severe vomiting and diarrhea accompanied by significant fluid loss from the body. It may also cause heart rhythm abnormalities and seizures. The Department of Horticultural Science at North Carolina State University considers cyclamen to be "toxic only if large quantities eaten", however.
Amaryllis produces clusters of beautiful, trumpet-shaped flowers that come in a variety of lovely colors, including a deep Christmas red. The plants are generally easy to care for and are beautiful additions to a home. Unfortunately, Amaryllis is potentially toxic for people and pets.
Amaryllis contains a toxin called lycorine, which is most concentrated in the bulb of the plant. This is the same toxin that is present in daffodil bulbs. Eating bulb tissue (or a very large amount of leaf or flower tissue) can cause stomach upset, nausea, vomiting, diarrhea, tremors and convulsions.
The potentially harmful effects of Amaryllis are reflected in an alternate name for one species of the plant, which is belladonna lily. Belladonna is another name for the deadly nightshade plant, which is very poisonous.
The ASPCA website contains a list of plants that are toxic for cats, dogs and horses. It states that Amaryllis is toxic for pets and lists similar symptoms to those that appear in humans.
The Christmas rose, or Helleborus niger, has pretty white flowers that resemble wild roses in form (though not always in color). It flowers in the middle of winter and is a delightful sight at Christmas time.
The flowers are white or pale pink and may be single or double. A double flower has more than one layer of petals. In the case of Helleborus niger, however, the "petals" are actually sepals. The real petals are inconspicuous.
The Christmas rose is another poisonous plant whose toxicity depends on the amount that's eaten. Eating the plant can result in a burning sensation in the mouth and throat, abdominal cramps, nausea, vomiting, diarrhea, weakness, depression and a slow heartbeat.
The Jerusalem cherry (Solanum pseudocapsicum) is a member of the nightshade family of plants. It produces orange-red berries that can add to the festive atmosphere in a home at Christmas time. The plant is also known as the winter cherry and the Christmas cherry.
The fruits of the Jerusalem cherry are sometimes confused with cherry tomatoes. This is a serious mistake, since Solanum pseudocapsicum is poisonous. The plant contains a toxin called solanocapsine. The leaves and unripe fruit contain the highest concentration of the toxin.
The assessments of the Jerusalem cherry's danger vary widely and range all the way from "mildly poisonous" to "deadly". It seems like a good idea for families with young children or pets to avoid this plant and err on the side of safety. Symptoms of poisoning include headache, stomach pain, vomiting, diarrhea, drowsiness and slow breathing.
I've read that African violets in bloom may be hard to find at Christmas, but they are available from November onwards in my local supermarket. They are obviously designed to attract the Christmas market since they are located right next to the Christmas cacti and are often placed inside little carrying bags that are decorated with Christmas scenes.
African violets don't have typical Christmas colors, especially the purple or blue forms, but they are pretty and colorful plants. They are available with pink flowers for people who prefer this color and feel that it matches the Christmas theme better. It's always nice to have flowers in bloom at Christmas time, though, whatever their color. Very importantly, African violets aren't toxic for people or pets.
Your Favorite Potted Christmas Plant
What is your favorite Christmas plant that is available in a pot (without considering toxicity)?
Christmas Trees and Greenery
Many people wouldn't dream of celebrating Christmas without a Christmas tree. In some homes the tree may be an artificial one, but many families still prefer to bring a real tree into their home.
Evergreens make good Christmas trees and provide branches that become part of Christmas wreaths and table centerpieces. They also provide cones, which add a nice touch to holiday decorations.
Firs, spruce, pine trees and cedars are the trees that are most often used as Christmas trees and as greenery for decorations. They are only very mildly toxic and usually cause no problem, since children and pets are generally uninterested in eating them. The needles would be prickly and painful to eat. If they were put into the mouth or swallowed they would likely injure the lining of the mouth and the digestive tract. The decorations on a tree or centerpiece are usually more interesting and potentially more dangerous for children and pets than the plant itself.
A relatively minor problem is that some evergreens that are brought indoors at Christmas, such as cedar, produce an oil that can irritate the skin (and the mouth). I have to wear gloves and long sleeves when I'm handling cedar or I end up with an itchy rash where the leaves have brushed against me. Another point to consider is that while the Christmas tree itself may not be a problem, the additives placed in the tree water may be harmful for pets.
Your Favorite Cut Christmas. Plant
What is your favorite Christmas plant that is available in a cut form (without considering toxicity)?
The Toxicity of Plants - Some Points to Consider
Some plant poisons are dangerous for everyone, even when ingested in tiny quantities. In other cases, the degree of toxicity varies. Toxicity of a plant is determined by:
- the nature of the poison
- the plant part that is eaten
- the concentration of the poison in that part at the time of ingestion
- the amount of plant material that is eaten
- the body size of the person or animal ingesting the poison
- the health of the individual ingesting the poison
- individual susceptibility to harm from the poison
Some of these factors are unknown, so it's wise to be very careful with toxic plants.
Mildly Toxic and Very Toxic Plants
People who want to buy plants for Christmas should think about their individual circumstances. Factors that should be considered include the age of any children in the family, the presence and type of pets in the home and the potential toxicity of the plants.
Most people would never bring a very toxic plant into a home which contains young children and pets. It might not be so easy to make a decision about mildly toxic plants. It certainly wouldn't be a pleasant Christmas for a child or pet who develops a gastrointestinal upset due to eating a plant. Some people may have a safe place to put plants that is out of reach of children and pets, however. In other cases a plant may have such a low toxicity that a person may not be worried about bringing the plant indoors.
Luckily, non-toxic Christmas plants are available. I love my pets and I enjoy having house plants in my home. We all get on very well together!
References and Further Reading
© 2013 Linda Crampton