The English and Poison Ivies are widely known for their invasive nature in the garden and the irritating effects that it has on the skin. A gardener or child who has had the misfortunate of touching one of these ivies with their bare hands will recount the frustrating itch. Both of these plants have a lot in common but are also distinct in their own ways. Can you tell them apart?
The English Ivy and Poison Ivy are similar plants in that they are both highly invasive species, grow berries, and produce chemicals that cause skin irritation. Despite both of these plants being toxic, they have medicinal uses to treat various illnesses for humans. While these ivies share similar characteristics, they can easily be distinguished by the leaf structure.
As these vines are quite common in the forests and gardens, I’ve written this article to help you identify the similarities and differences between them.
The Leaf Differences
The English Ivy (scientific name: Hedera helix) has dark green leaves with white veins that feel waxy to somewhat leathery. The foliage is often three to five-lobed leaves that alternate each side of the stem. When exposed to additional lighting, clusters of small yellow-green flowers are produced during the fall.
The Poison Ivy (scientific name: Toxicodendron radicans) has three smooth-edged leaflets on a reddish stem. The leaflets have veins running to the leaf edge. Leaf color varies widely from yellowish green to reddish-green to dark green. Unlike the English Ivy, the Poison Ivy has a compound of leaves, with each leaf composed of three leaflets.
As you can see from the above images, the Poison Ivy is distinctively different from the English Ivy in that each leaf comes in clusters of three leaflets. The English Ivy has singular leaflets growing from the stem.
Another telling difference between the two plants is that the poison Ivy is deciduous and has no leaves during winter, whereas the English Ivy has leaves all year round.
Both are Invasive Plants
The English Ivy is an aggressive climbing vine that clings onto walls, fences, tree trunks, and virtually anything it can grip onto. It does this by growing aerial roots and squeezing into gaps of wooden surfaces. The plant anchors itself securely by excreting an adhesive substance and using its tiny root hairs to hold onto its substrate. This gluing process is the reason why paint peels off when we try to remove the vine from the house walls.
The English Ivy spreads by forming new plants from the cut or broken stems that can root in the soil. It spreads to new distances by seed carried by frugivorous birds.
The Poison Ivy is also an aggressive climbing vine that uses its hairy roots to ascend on wooden surfaces. In the forests, it’s a common sight to see them climb up and wrap around the trunks of trees. You may see these plants dominate utility poles, old wooden houses, and fences along a walking path on the streets.
Practical Uses of the English and Poison Ivies
Despite its abundance, the English Ivy is still being sold at nurseries in the U.S, and landscaping companies continue to use it in commercial and residential projects. This plant is often used as a roadside planting because it is low-maintenance, grows in harsh conditions, and provides a uniform groundcover appearance.
Interestingly, this common ornamental plant has medicinal potential.
According to an observational study, herbal medicine containing extracts of the English Ivy were found to be very effective against cough and blockage of airways in children. Other sources also claim that the English ivy improves lung function in people with bronchial swelling and the removal of mucus build-up.
Similarly, the Poison Ivy has been identified as having medicinal properties to treat several conditions such as cramps, sprains, viral infections, and arthritis. Such medicine is available as an over-the-counter pill, capsule, ointment, and gel forms. However, the effectiveness of these medications is unclear.
Unlike the English Ivy, the Poison Ivy is hardly used as a houseplant. As the Poison Ivy is highly irritating on the skin when touched, it’s no surprise that it would be an undesirable houseplant, especially for children.
Both are Toxic
Both the English and Poison Ivies can cause allergic reactions. Gardeners who try to trim these plants without protective clothing often find themselves having allergic contact dermatitis. Kids who play with these ivies or climb trees covered in them may experience redness, itching, swollen skin, or blisters.
The English Ivy appears to be more populated but less irritating than the Poison Ivy. However, for the unlucky few who have severe reactions from the English Ivy (such as Lizbeth Mang‘s story), one can experience weeks of unbearable rashes on the arms, neck, face, and the rest of the body.
The Poison Ivy appears to be more irritating as it produces a chemical called urushiol. This sticky, pale yellow oil causes an allergic reaction in humans. The urushiol is not poisonous, but only when it is absorbed through our skin that It comes with the skin proteins that cause an allergic reaction.
According to the American Skin Association, about 85 percent of the American population are allergic to poison ivy, and about 10 to 15 percent are highly allergic. This is the most common allergic reaction in the U.S and affects as many as 50 million Americans each year.
Shared Common Problems
Both the English Ivy and Poison are invasive spreaders, but the English Ivy appears to be more the contagious grower. This might be because the English Ivy is an evergreen plant that has leaves throughout the year, whereas the Poison Ivy loses its leaves during the winter season, so it does not photosynthesis as quickly.
As an evergreen vine, the English Ivy has the advantage of being able to photosynthesize during the winter months while deciduous trees are dormant. During this period, the vine has uninterrupted light, which allows it to grow more rapidly up the host tree’s trunk. This inhibits the leaves of the deciduous tree, thereby suppressing the growth of the host tree. As the vine reaches up to the canopy, the density of the vine with the weight of moisture increases the susceptibility of trees snapping during high winds. To make matters worse, the vines tangle among native understory, making removal incredibly difficult.
In areas of the U.S, the English Ivy invades deciduous forests to create an “Ivy desert.” This term describes a forested area with a limited number of canopy species with entangling English Ivy vine wildly climbing up tree trunks and reaching out into the canopy. The ground is also covered in a thick mat of ivy groundcover.
The English Ivy’s high level of adaptability to a range of light conditions enables the vine to dominate the forests with fluctuating light levels. This contagious spread changes the ecosystem of a forest by out-competing native plant communities of grasses, herbs, and trees, thereby reducing animal feeding habitats. The monoculture of the English Ivy suppresses the regeneration of a diverse ecosystem that can diminish the forest’s survivability.
Which one should I keep as a houseplant?
The English Ivy is a far more popular choice as a houseplant than the Poison Ivy. The English Ivy is a versatile houseplant that can be used in different situations, such as hanging baskets, pots, or trailing plants on the trellis. The Poison Ivy is more commonly viewed as a pest due to its highly irritable leaves.
The English and Poison Ivies are both invasive vines that spread aggressively using their hairy roots and twining stems that climb on surfaces. These plants are often regarded as pests when uncontrolled as they interrupt nearby native plants and cause skin irritation for humans. Despite their nuisances, both of these ivies may contain medicinal properties that provide natural relief against various disorders. However, more research is needed to prove the effectiveness of these ivies on humans.
If you’re looking to choose one of these plants as a houseplant, the English Ivy is the clear winner – provided that it’s grown in a controlled environment such as in a pot.
- King County
- The Spruce
- Journal of the Royal Society Interface
- Anne Okerman
- Ferreria Animal Hospital
- Pet Poison Helpline
- English Ivy by Meredith Leigh Collins
- Poison Ivy by James St. John
- English Ivy invading forest by Arlington County