Numerous species of periwinkle are grown as ornamental houseplants or garden vines and are widely popular for their groundcover, shiny green foliage, and small, funnel-like fragrant blooms, each with five petals.
The three most common species of Periwinkle plants are:
- Vinca major (Big periwinkle)
- Vinca minor (Lesser periwinkle)
- Catharanthus rosea (Madagascar periwinkle)
Which was formerly known as Vinca rosea.
These plants are hardy in the U.S. Department of Agriculture (USDA) zones 6 through 10.
These low-lying, herbaceous perennials prefer partial shade or full sun and ample moisture in the soil, especially during hot, dry weather.
These plants spread rapidly and provide a dense carpet of shiny green leaves.
The beautiful oval or heart-shaped leaves grow up to 2” to 3” inches in length.
The leaves grow in pairs along the stem.
Periwinkle plants produce beautiful spring flowers from April to May, which continue to adorn the gardens during the summer.
These fragrant, gorgeous flowers rise above the lush leaves and add spring color to the setting.
Growing in a range of hues including pink, violet, blue, purple, and lavender, each flower is up to 2” inches in size and has five showy petals.
Is Periwinkle Plant Poisonous?
Not all varieties out of the 30 species of Periwinkle plants are poisonous.
While Vinca major and minor rarely show mild toxicity, Catharanthus rosea is a highly poisonous variety.
This toxic periwinkle is also famous for its common names, such as:
- Madagascar Periwinkle
- Cape periwinkle
- Ammocallis rosea
- Catharanthine Catharanthus
- Catharanthus roseus
- Pink periwinkle
- Pervenche rose
- Old maid
- Lochnera rosea
- Magdalena Myrtle
- Running Myrtle
Madagascar periwinkle is regarded as a potentially toxic plant depending on the level of exposure and ingestion.
These are equally toxic to humans, cats, dogs, and horses.
This periwinkle plant consists of vinca alkaloids which are sometimes used to prepare medicines for people suffering from diabetes and high blood pressure.
It contains alkaloids which are often used in chemotherapy for selective poisoning of the cancer cells in humans and animals.
Hence, ingesting the Madagascar periwinkle in any way causes severe poisoning in pets and side effects in humans.
What Parts Of The Periwinkle Plant Are Poisonous?
All parts of the Madagascar periwinkle are poisonous.
These plants contain a wide range of naturally-occurring toxic alkaloids which cause poisoning when ingested.
There are over 130 chemical compounds found in these plants, such as vincristine and vinblastine, which attach themselves to the microtubules of the cells and impairs their ability to divide.
This restricts the development of the blood vessels in the body and impedes the production of microtubules.
These alkaloids cause cell death.
Vinca rosea also consists of harmful saponins and some other toxins like vindoline, vincamine, vincadifformine, akuammine, perivincine, reserpinine, and vinine.
The effects of all these alkaloids are not completely known yet; however, they are found to be hypotensive, which means consuming them would result in abnormally low blood pressure.
What Are The Symptoms Of Poisoning?
According to the findings of the Division of Agriculture at the University of Arkansas, the ingestion of Periwinkle plants can cause symptoms depending on the amount consumed.
The symptoms in humans range from mild stomach cramps, cardiac complications, reduction in blood pressure, and even systematic paralysis and death.
Since periwinkle plants are extremely unappetizing, the animals usually refrain from consuming them in larger quantities.
However, growing periwinkle as a houseplant puts your furry friend at risk.
According to the American Society for the Prevention of Cruelty to Animals (ASPCA), symptoms of Periwinkle poisoning in cats and dogs include depression, lack of coordination, vomiting, nausea, and diarrhea.
If the poisoning is more severe, your pet may experience seizures, tremors, abnormally low blood pressure, anxiety, and stroke.
While the poisoning is not fatal in most cases, it may result in progressive paralysis, coma, and even death in some rare cases.
How To Protect Yourself While Handling Periwinkle Plant?
Periwinkle plants are safe to handle and may not harm when touched; however, wash your hands thoroughly after pruning, cutting, or potting these plants as the toxins might have flowed on your hands.
To prevent accidental consumption, periwinkle plants should not be grown in areas exposed to small children, like preschool gardens, accessible home gardens, and low containers holding them as houseplants.
Supervise the children if taking them out in a park or any other public place which might have periwinkle plants.
Keep these plants out of the reach of the pets.
If you observe any symptoms in your cat or dog, check for any plant remnants around their mouth and bite marks on the plant.
Promptly contact the local poison control or consult the veterinarian if your animal shows signs of poisoning.