Madagascar periwinkle is a star-performing container plant available in a rainbow of colors. Here’s how to grow this heat-loving annual in the desert.
If you love flowers, but find that many annuals fade or are fussy during the heat of the summer, look no further than Madagascar periwinkle (Catharanthus roseus).
These flowers are ubiquitous in containers in the desert southwest… with good reason. These are the “energizer bunnies” of desert potted plants — they keep on going even during the worst heat waves.
Harlow Gardens, Tucson’s oldest family-run nursery, reports that Madagascar periwinkle is consistently their top selling summer annual. Their customers love it because it flowers profusely all summer, has attractive green leaves, and can take the heat.
Why I Like This Plant
- Non-stop flowers spring through fall
- Glossy, true-green leaves
- Thrives in summer heat
- Low maintenance, low-litter
- Attracts bees and butterflies
- Annual that often acts like a perennial
Things to Watch Out For
- Toxic to humans, cats, dogs, and horses
- Prone to some insects and “vinca wilt”
- Needs frequent watering to look its best
Optimal Growing Conditions
If you’re thinking of planting Madagascar periwinkle in your garden, here are the key factors to keep in mind.
Temperature
Madagascar periwinkle should be grown in USDA Hardiness Zones 9 – 11. It is extremely heat tolerant and can handle the heat of Phoenix.
But it is not cold-hardy and dies back with the first frost. However, in climates with mild winters and occasional freezes, plants can survive and rebound in the spring, especially if you cover them during cold snaps or keep them on a covered patio.
Is Madagascar periwinkle an annual or a perennial?
It depends.
It’s considered a perennial in zones 10 & 11 and an annual in zone 9.
However, many zone 9 gardeners find they come back in the spring.
Sun Exposure
Madagascar periwinkle performs best in full sun or part shade. Avoid exposing them to reflected heat. They appreciate a little relief from afternoon sun in the summer.
Size and Growth Rate
Madagascar periwinkle is a fast grower. When started from seeds, new plants start flowering within 6 to 8 weeks. Each plant reaches a size of 1′ tall by 1.5′ wide, however, it’s usually planted in groups where they form mounds of color.
Soil
Whether planted in a container or in the ground, Madagascar periwinkle needs well-drained soil to avoid root rot. It’s prone to chlorosis in sandy soils.
It’s a good practice to change out the soil every few years when growing it in pots. Continually planting Madagascar periwinkle in the same pot with the same soil can ultimately lead to vinca wilt.
Madagascar Periwinkle:
The Essentials
| Common Names | Madagascar periwinkle, vinca |
| Scientific Name | Catharanthus roseus |
| Origin | Madagascar |
| Plant Type | Annual/perennial |
| USDA Zones | Zones 9 – 11 |
| Cold Hardiness | To 30℉ |
| Flower Colors | Red, pink, lavender, white |
| Flower Season | Spring, summer, fall |
| Mature Size | 1′ high x 1.5’ wide |
| Growth Rate | Moderate to fast |
| Sun Tolerance | Full, part sun |
| Water Needs | Low to moderate |
| Pests & Diseases | Vinca wilt, root rot, insects |
| Toxicity | Toxic to humans, dogs, cats, horses |
| Wildlife | Attracts butterflies, bees Deer, rabbit resistant |
How to Care for Madagascar Periwinkle
If you’ve decided to grow Madagascar periwinkle in your garden, you’ll need to know how to maintain it. Here’s how to water, fertilize, and trim it to keep it healthy and looking its best.
When to Plant
While nurseries are well-stocked with Madagascar periwinkle and other summer annuals early in spring, resist the urge to plant them until your nighttime temperatures stay above 55°F.
While you may see plants for sale in the fall, you can give them a try, but they won’t have much time to get established and might not make it through the winter.
How to Water
While somewhat drought tolerant, these plants are happiest when watered frequently, but don’t let them stay continually wet. To avoid root rot, let the soil dry out between waterings.
Should You Fertilize?
Since Madagascar periwinkle is not native and flowers profusely, plants benefit from fertilizer. To ensure maximum blooms, lightly fertilize them two to three times between spring and fall.
How to Trim
These plants don’t need pruning or deadheading, but you can occasionally pinch them back if they get leggy or if you want to encourage bushiness and more flowers.
Insect Pests
Madagascar periwinkle can get aphids, spider mites, or whiteflies. If you see these on your plants, spray them away with your hose or use insecticidal soap.
Vinca Wilt: Cause & Prevention
Madagascar periwinkles wilt when thirsty, and a quick watering usually perks them right up. But if you find that your plants don’t recover with water, they might have vinca wilt, a fatal infection that prevents plants from taking up water.
It seems there is more than one organism causing wilt symptoms including Fusarium (fungus), Phytophthora (fungus), Rhizoctonia (fungus), and Spiroplasma (bacteria).
But all you need to know is that if your plants are wilted, and don’t rebound when watered, you should assume they have vinca wilt.
There’s no effective cure, so you need to remove and dispose of affected plants. Don’t plant new plants in the same soil, since the spores can live in soil for years. You can reuse your container, but scrub it with hot, soapy water and let it dry in full sun first. Some sources recommend using a dilute solution of bleach as a disinfectant.
One preventative measure you can take is to rotate your plants to avoid planting Madagascar periwinkle in the same pot or soil every year.
Is Madagascar Periwinkle Invasive?
Madagascar periwinkle often reseeds in desert gardens. They are usually welcome volunteers and rarely reseed to the point of being a nuisance.
However, Madagascar periwinkle has widely naturalized around the world, including parts of the US — Florida, Alabama, and California. And in some pockets in the US, it has become invasive.
So far, it has not escaped cultivation in the desert southwest. It’s believed its range here is limited by lack of water and cold winter temperatures.
Madagascar Periwinkle Cultivars
Madagascar periwinkle has dozens of cultivars and new ones are introduced every year. The main difference between most of them is flower color. They come in a rainbow of colors — white, dark red, lavender, peach, and every imaginable shade of pink.
Most Madagascar periwinkles are upright, but there are now trailing varieties that cascade when grown in pots and form a ground cover when planted in the ground. They grow half a foot tall and 2 feet wide.
Vinca Name Confusion
Madagascar periwinkle has many (too many!) alternative common names including:
- periwinkle
- vinca
- rose periwinkle
- rosie periwinkle
- old-maid periwinkle
- annual vinca
- running myrtle
It’s often mistaken for another plant, Vinca major, that has the same common names — vinca and periwinkle. Let’s clear up the confusion between these two plants!
Why Vinca? Why Periwinkle?
Madagascar periwinkle’s former scientific name was Vinca roseus, landing it in the same genus as greater periwinkle (Vinca major), which is why both plants are called vinca.
Fortunately, it’s easy to tell them apart visually and by habitat. Vinca major is a shade and moisture-loving, vine-like ground cover that forms dense mats.
While the flowers look similar to those of Madagascar periwinkle, they are smaller and come in one color – a light purple-blue (a color known as periwinkle, the source for another one of its common names).
Here’s a chart with some of the major differences between them:
| Top Common names | Madagascar periwinkle, Vinca | Periwinkle, Vinca |
| Scientific Name | Catharanthus roseus (formerly Vinca roseus) | Vinca major |
| Flower Colors | White, red, lilac, shades of pink | Purple-blue |
| Form | Upright | Ground cover |
| Preferred Habitat | Sunny, hot, dry | Shady, moist |
Plant Lover Facts
Madagascar periwinkle has a long history of medicinal use and was used in both Ayurvedic and Chinese healing practices to treat diabetes, hypertension, and malaria.
In the 1950s, several vinca alkaloids were discovered that had great medical potential. They are now used in treating several types of cancer.
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Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for 15 years.
