How to Grow Snail Vine Plants

White and purple shell flowers on vine with delicate oval leaves

 Sebastiao Pereira-Nunes / Flickr / CC BY 2.0

The snail vine is a tender perennial that grows in regions free of frost. It bears beautiful small flowers that range from pale pink to lavender, shaped like curly shells. The flowers resemble sweet peas in shape if not in growth habit.

The blossoms are very showy, staring out as creamy white buds and then unfurling to slightly brighter colors including lavender, pink, coral and purple. The flowers are also fragrant, with the scent being described as a cross between hyacinth and wisteria.

The leaves are also attractive and make an excellent cover for a wall or fence, as the fast-growing vine grows up to fifteen or even twenty feet long. It can be easily pruned to fit your needs.

There is a similar plant also known as snail vine or shell vine which is not the true Cochliasanthus caracalla. Its botanical name is Phaseolus giganteus. While the vine and flowers have a very similar appearance, the main difference is that the true snail vine has fragrant flowers.

Botanical Name Cochliasanthus caracalla (formerly Vigna caracalla)
Common Name Snail vine, snail flowers, shell flowers, corkscrew vine
Plant Type  Tender perennial vine
Mature Size 15 to 20 feet
Sun Exposure Partial to full sun
Soil Type Well drained fertile soil
Soil pH Slightly acidic to neutral
Bloom Time Midsummer to early autumn
Flower Color white buds, pale pink to lavender flowers
Hardiness Zones USDA 9 to 11
Native Areas Central and South America
Toxicity Non toxic 
Wisteria blue flower of the snail vine, close up with green leaves in background
The snail vine's flowers come in a range of colors, beginning with white buds and then turning shades from pale to coral pink or a range of purples, including this lovely wisteria blue.  Barbara / Flickr / CC BY 2.0

Snail Vine Plant Care

This beautiful, fast-growing vine can also be grown as an annual, and if cared for properly, will provide lovely fragrant flowers for up to eight weeks, and abundant leaves all summer long.

Light

The snail vine does fine in partial sun. Full sun in a warm growing zone might prove a bit much on a hot summers day, so keep an eye on your plant in case it shows signs of wilting, burning or drying out.

If you're perennializing your snail vine, choose a spot that gets between three and four hours of direct sun, preferably in the morning. Dappled shade is a good option too.

In more temperate zones, when you are growing snail vine as an annual, or overwintering it in a container, it can handle more sun.

Soil

Snail vine likes a somewhat rich, loamy, and well-drained soil. You can add compost and peat moss if your soil needs some amendments.

Water

Being tropical, the snail vine does like regular irrigation. Water deeply when the top two inches of the soil has dried out and let the water soak in. Misting your snail vine will also provide the humid environment it loves, and keep the blossoms from drying out on a particularly hot day.

Temperature and Humidity

This plant likes a bit of humidity in the air to create the tropical conditions it thrives in. If you're planting snail vine in your garden in a USDA zone between 9 and 11, choose a spot with good drainage.

Pruning

If growing as a perennial, the snail vine likes regular trimming to get rid of dead foliage and scraggly vines. Trim back to the new wood in the spring, keeping a few strong vines viable until it starts producing new growth.

You can trim your snail vine all season, as its vigorous growing habit responds very well to regular light pruning.

Propagating Snail Vine Plants

Snail vine grows fairly easily from seed or cuttings, provided your growing conditions are right.

Plant seeds (collected from pods before cold temperatures might damage them) in a moist, slightly acidic potting medium with plenty of perlite or vermiculite for good drainage. Keep in a sunny window. Once established, you can transfer to a larger container.

Overwintering

This is a tropical plant that can't survive outdoors in cold regions, but some growers bring it inside for the winter. Some nurseries will sell snail vine plants to transplant into your garden. But if your hardiness zone is below 9, you should plant in a container and then bring it inside for the winter.

You can cut back the vines and they will grow back the following season; don't worry about killing your snail vine, they grow very vigorously in the warmth and sunlight.

These vines like a lot of direct sunlight. Over the winter, if you have a sunny window area with at least four hours of sun per day, it should do fine until you can bring it outdoors again after all danger of frost has passed.

Common Pests/Diseases

These plants are not generally bothered by insects; however, they are pollinated by ants. This pollination will last for a few days after the white buds first appear.

The ants are attracted to the sweet nectar inside the closed buds (similar to how peonies attract ants just before their petals unfurl). Interfering with this process means the plant won't produce seeds, so try to leave the ants alone to do their business. They'll depart soon and your snail vine will be healthier for their activity.