Snail vine is a vigorous vine with charming, fragrant purple flowers that, unsurprisingly, are shaped like snails. Here’s how to plant and care for this Latin American native.
Snail vine (Vigna caracalla) is a vigorous semi-evergreen vine with some of the most interesting flowers you’ll ever see. They have curly petals and resemble snails, corkscrews, or tortellini. As each flower matures, it transitions from purple and white to creamy yellow.
Flowers emit a delightful fragrance that’s been compared to hyacinth or jasmine. The fragrance attracts bees and butterflies and is so powerful it can be noticed 15 feet away!
Snail vine is a member of the legume family and produces long, skinny bean-like pods after flowering.
Even though it’s native to tropical areas in Latin America (Mexico, Central America, South America), it thrives in hot desert gardens, provided it gets enough water.
In locations where there is no frost, it stays evergreen, otherwise, it loses its leaves in winter.
Why I Like This Plant
- Charming snail-shaped, fragrant purple flowers
- Grows fast
- Attracts bees and butterflies
- No thorns, not toxic, no pests
Things to Watch Out For
Snail vine is deceptively vigorous. It can grow 30 feet per year. Once it matures, be prepared to remove a large tangle of dead vines every spring.
It can be messy when it loses its leaves in the winter.
If you don’t provide adequate support, it will turn into a scrambling ground cover that smothers everything in its path.
Flowers are mostly pollinated by ants. So this vine is not a good choice if you don’t like seeing ants on your plants. 🐜🐜🐜
Optimal Growing Conditions
If you’re thinking of adding a snail vine to your garden, you need to find a suitable place that will keep it healthy and looking good… while minimizing maintenance for you.
Here are the key factors to keep in mind.
Temperature
Snail vine should be grown in USDA Hardiness Zones 9 – 11. In frost-free locations, it stays evergreen, otherwise it loses its leaves.
It doesn’t like the cold and shows signs of damage once the temperature drops below 40℉. However, it’s root-hardy down to 20℉ and rebounds quickly in the spring.
Sun Exposure
Snail vine can be grown in full sun to part shade, but struggles when grown against a hot, west-facing wall.
Size and Growth Rate
Snail vine is a large, robust vine. It typically reaches a size of 10 to 20 feet tall and wide. A plant’s mature size depends on how it’s watered and pruned, and whether it dies back in the winter.
However, it can get substantially bigger than that in the desert southwest. According to the University of Arizona, it can grow 30 feet in its first year! So be forewarned that snail vine might turn into a monster plant in your Arizona garden.
Pro Tip!
If your snail vine is getting too vigorous,
reduce watering to control rampant growth.
Soil
Snail vine grows well in any desert soil, from sandy or rocky to loam, provided it’s well-draining. Since it originates in the tropics, it’s happy in moist soil.
Other Location Considerations
Snail vine has no thorns and is non-toxic, making it relatively user-friendly. But since it attracts bees and ants, you might not want to plant this near seating areas or where children or pets play.
It climbs by tendrils and readily grows up any nearby support structure such as a trellis, lattice, or fence. It forms a dense screen that makes an attractive wall of green even when it’s not in bloom.
Snail Vine:
The Essentials
| Common Name | Snail vine |
| Scientific Name | Vigna caracalla |
| Origin | Latin America |
| Plant Type | Semi-deciduous vine |
| USDA Zones | Zones 9 – 11 |
| Cold Hardiness | To 20℉, damage at 40℉ |
| Flower Color | Purple |
| Flower Season | Spring, summer, fall |
| Mature Size | 10-20′ high x 10-20′ wide |
| Growth Rate | Fast |
| Sun Tolerance | Full, part, reflected sun |
| Water Needs | Moderate to high |
| Pests & Diseases | None |
| Garden Friendly | No thorns, non-toxic |
| Wildlife | Attracts bees, butterflies |
How to Plant
The rule of thumb when planting any vine in the desert is to dig a hole three times as wide as the root ball but no deeper. Amending the soil is not recommended. Counterintuitively, backfilling with the same native soil you just dug up helps your plant develop a stronger root system.
When to Plant
The best time to plant snail vine is in the fall. This gives your vine three seasons to grow roots and get established before the following summer.
The second best time is in spring, the earlier the better. This still gives your plant time to get established before the intense heat of June arrives.
Additionally, you can grow snail vine from seed. You can sow them directly into the ground after your last frost date, or start them indoors.
How to Care for Snail Vine
Whether you’ve recently planted a snail vine or have an existing plant in your yard, here’s how to take care of it to keep it healthy and looking its best.
How to Water New Plants
Once you’ve got your snail vine in the ground, watering is your most immediate concern. Here’s a recommended watering schedule for new vines planted in the spring or fall.
| Weeks 1 & 2 | Every 3 – 4 days |
| Weeks 3 & 4 | Every 6 – 7 days |
| Weeks 5 & 6 | Every 7 – 10 days |
| Weeks 7 & 8 | Every 10 – 14 days |
After week 8, gradually revise your watering schedule, depending on the season.
How to Water Established Plants
Snail vine needs a moderate-to-high amount of water and regular, deep irrigation. Here’s a suggested schedule.
| Spring & Fall | Every 10 days |
| Summer | Every 7 days |
| Winter | Every 14 days |
Should You Fertilize?
Since snail vine is not a desert native and is a prolific bloomer, it benefits from an application of fertilizer in the spring.
Snail vine is a member of the legume family (Fabaceae). The roots of legumes contain bacteria which “fix” nitrogen, turning nitrogen in the air into a form plants can use. Therefore, apply a low-nitrogen fertilizer.
How to Prune
Snail vine benefits from a hard prune in the early spring to reinvigorate it, shape it, and keep its size under control.
Plant Lover Facts
Snail vine goes by many common names including snail creeper, snail bean, snail flower, corkscrew flower, corkscrew vine, and caracalla bean.
Previous scientific names that are still in use are Phaseolus caracalla and Cochliasanthus caracalla.
Thomas Jefferson, one of America’s earliest agronomists, was so enamored of this plant he called it “the most beautiful bean in the world.” Snail vines are sold by the Thomas Jefferson Foundation to support Monticello.
Have you grown this plant?
Was it a “hit” or a “miss” in your garden?
Please share your experience in the comments below!
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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.
Photo Credits
Alex Lomas, CC BY-SA 2.0, via Wikimedia Commons
Arizona State University’s Virtual Library of Phoenix Landscape Plants