Dioscorea

( dye - uh - SKOR - ee - uh )

At-A-Glance Information

This genus of tuberous perennial (sometimes grown as annual) vines is known for producing starchy tubers that are edible after processing. In some species, vines produce aerial bulbils that are also processed and eaten. They are primarily native to tropical and subtropical regions, and feature twining stems that reach up to 30 feet long. Flowers are inconspicuous and green foliage is heart-shaped. Use these vines as members of edible gardens, for vertical interest on trellises or arbors, or allow them to grow along the ground as a groundcover. Take care when planting these vines in the landscape, as plant parts are toxic to pets and humans if ingested.

Dioscorea Species and Varietals

The genus Daucus is a member of the plant family Apiaceae, and includes around 75 distinct species. The genus was named to honor the Greek physician and botanist Dioscorides. These tropical and subtropical plants grow well in USDA hardiness zones 9a-12b, though this varies somewhat by species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Dioscorea alata (Ube, Ubi, Purple Yam, Greater Yam, Winged Yam, Water Yam, White Yam, Kand, Beniimo)
This species is native to tropical areas of Asia and Oceania, and has been cultivated by humans since ancient times. The tubers are typically vivid purple to bright lavender in color, adding both flavor and bright hues to dishes. The tubers are mildly sweet, earthy and nutty tasting, and are reminiscent of Sweet Potato or Yaro. This species grows well in USDA hardiness zones 9-12, preferring temperatures over 70 degrees Fahrenheit. This species is considered highly invasive in the United States (Florida, Georgia, Louisiana, Alabama, Puerto Rico, Virgin Islands, Hawai'i), Africa, and various islands in the Indian and Pacific Oceans.

Dioscorea bulbifera (Air Potato, Air Yam, Bitter Yam, Cheeky Yam, Potato Yam, Parsnip Yam, Up-Yam)
These plants, native to Africa, Asia, and northern Australia, are widely cultivated for their bulbils instead of their tuber roots. They grow well in USDA hardiness zones 9a-12b. The species forms a perennial vining plant that forms bulbils in the leaf axils of stems, which are used as a food crop. These plants can grow very quickly, up to 8 inches per day, and can re-sprout fully from their underground tuber root. Flowers are small and white. Air Potato is considered highly invasive in the United States (Florida, Alabama, Georgia, Louisiana, Mississippi, Texas, Hawai'i, Puerto Rico).

Dioscorea cayenensis (Guinea Yam, Yellow Yam, Yellow Guinea Yam, White Name, Attoto Yam)
This species is native to and widely consumed in West Africa. Individual plants produce vines that can reach up to 32-40 feet long. Tubers grow to weigh between 6 and 11 lbs. Cultivar 'Kokoro' is a very commonly planted variety of this species. These plants are suited for USDA hardiness zones 10-12.

Dioscorea communis (Tamus communis) (Black Bryony, Lady's Seal, Black Bindweed, Devil's Cherry, Oxberry, Murrain Berry)
These plants are climbing vines that reach between 6.5 and 13 feet long at maturity. Leaves are green and heart-shaped, and flowers are inconspicuous and greenish-yellow. All parts of these plants, especially the berries, are poisonous; do not consume.

Dioscorea dumetorum (Bitter Yam, Cluster Yam, Trifoliate Yam, Three-Leaved Yam)
This species is native to sub-Saharan Africa, and produces green foliage and brown flowers. The straight, wild species is toxic, though edible cultivars have been developed in the plant's native range. All parts of these plants, especially the berries, are poisonous; do not consume.

Dioscorea elephantipes (Elephant's Foot, Hottentot Bread, Tortoise Back Plant, Turtle Back Plant, Turtle Shell)
This species is native to South Africa, and is a deciduous climbing vine. It sends out vining stems from a large, partially buried tuberous root or caudex, which grows slowly but can reach impressive sizes (up to 10 feet in circumference). The tuber is rich in starch, and covered in thick, hard, corky plates. These plants are mainly cultivated as indoor plants, prized for their curious-looking knobby tuber.

Dioscorea esculenta (Lesser Yam, Gembili, Tugi, Apali, Cheru Kizhangu, Kaate Kanaga, Chinese Yam, Asiatic Yam, Spiny Yam, Goa Potato, Birch Rind Yam, Sweet Yam)
Native to the islands of Southeast Asia, this species is grown for its edible tubers, though is less commonly cultivated than Dioscorea alata. Stems are round and thin, and produce large black spines. Leaves are soft, heart-shaped and green.

Dioscorea hispida (Indian Three-Leaved Yam, Gadung, Asiatic Bitter Yam, Intoxicating Yam, Nami)
This species of Yam is native to southeast Asia. Although it is edible, it does take some processing to render it non-poisonous first. Toxins are commonly leached out in running water, and then the tuber is grated. These plants are suitable for USDA growing zones 8-12. Do not consume plant parts raw; they are toxic.

Dioscorea polystachya (Dioscorea batatas, Dioscorea oppositifolia) (Chinese Yam, Cinnamon-Vine, Chinese Potato, Ma, Huaishan, Waaih Saan, Japanese Mountain Yam, Korean Yam, Shan Yao)
This species forms a perennial climbing vine native to Eastern Asia. Tuber roots are edible, widely cultivated in its native range. Vines typically reach 16.5 feet long at the maximum, and have green heart-shaped foliage. Bulbils, or 'Yam Berries' form in leaf axils, able to produce new plants. Flowers are cinnamon-scented. These vines are suitable for growing in USDA hardiness zones 4-11. This species is considered invasive in some areas of the United States (New York, Pennsylvania, North Carolina, Tennessee, South Carolina, Ohio, Indiana, Illinois).

Dioscorea trifida (Indian Yam, Cush-Cush, Yampee, Mapuey, Inhame, Tabena, Sacha Papa, Nampi)
These plants can exceed 10 feet long, and produce green flowers that are borne in leaf axils. This species is cultivated for its edible tuber roots, especially in South America and the Caribbean. The roots can be white, purple, or black and can be baked or boiled. This species is considered invasive in Puerto Rico and Hispaniola.

Dioscorea villosa (Wild Yam, Colic Root, Rheumatism Root, Devil's Bones, Fourleaf Yam, Yellow Yam, Atlantic Yam)
This species is native to the eastern and southeastern areas of North America, and produces heart shaped green foliage. Flowers are green to brown or white. These plants grow from tuberous roots and produce vining stems that reach up to between 5 and 30 feet long. Colic Root plants grow well in USDA hardiness zones 4-9.

Caring for Dioscorea

Take care when planting these vines in the landscape, as plant parts are toxic to pets and humans if ingested. Plant Dioscorea in springtime after all danger of frost has passed; these vines are not frost-hardy. Plant these vines in full sun exposure; between 6 and 8 hours per day is best. They prefer soil that is well-draining and fertile, with a pH of between 5.5 and 7.0 (slightly acidic to neutral), and appreciate a lot of organic matter. If local soil is poor or has bad structure, make sure to amend the planting site with plenty of organic matter and/or compost before installing. Apply a thick layer of mulch around the base of the plant after installation, ensuring that mulch stays at least a few inches away from the stems. This will increase soil moisture retention, suppress weed growth, and maintain a constant soil temperature. Water new plantings regularly as they establish themselves in the landscape. At maturity, Dioscorea vines appreciate infrequent deep waterings. If cultivating these vines for their edible (when processed) parts, keep soil consistently moist, watering whenever the top 1-2 inches of soil feels dry to the touch.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season. Vines can be cut back to the ground in early springtime; they will regrow from their base in the same season. Pruning Dioscorea vines regularly can limit their spread and invasive potential. In tropical and subtropical zones, these vines are treated as perennials, surviving for 5 to 10 years in the garden before needing to be replaced. In cooler, temperate zones, they are grown as annuals, pulled and harvested at the end of each growing season and then composted.

Harvesting Dioscorea
Harvested parts of these vines should never be eaten raw, as they are highly toxic and can cause severe illness. Wild types are more toxic than others; ensure correct species identification and engage in correct preparation before consuming. Air Potato vines are typically harvested in fall and winter, when aerial tubers (bulbils) turn dark brown and begin to fall from their attachments. Shake vines to release. The underground tubers can also be harvested at this time. Gently work in with a trowel or shovel from the outside of the root zone, taking care to not damage the roots. Pull the plant up from the ground, tap roots off and rinse them. These roots, both aerial and underground, need to be processed to be edible. Slice and boil until tender (about 20 minutes), changing the water multiple times during the cooking process to remove bitterness.

Disclaimer: Information contained on this website is strictly and categorically intended as a reference to be used in conjunction with experts in your area. Foraging and consumption of plant parts should never begin without the guidance and approval of a local plant specialist. The providers of this website accept no liability for the use or misuse of information contained in this website.

Propagation

Dioscorea, or Air Potato, vines can be propagated by cutting or division. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your vine , follow the instructions below:

Propagating Dioscorea by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
In late summer or early fall, choose the plant that you'd like to propagate. Ensure that the plant has had a good watering the night before, as this will improve the chances the cutting will take root. Cut one or more 6-8 inch softwood or semi-hardwood portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. It should be kept in warm, sunny conditions in a protected area. Water whenever the soil is dry under the top layer. After about four to six weeks have passed, the cutting should be rooted. New growth indicates the formation of roots.
Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when the vine can be hardened off and then planted outdoors.

Dioscorea seeds are held inside of seed pods after flowers have faded.

Dioscorea seeds are light brown, flat, and equipped with an apical wing designed for wind dispersal.

Problems and Pests

Many species of Dioscorea vine are considered invasive in tropical and subtropical regions worldwide. For more information, see the species descriptions above; check with local authorities before planting. Dioscorea, or Air Potato, vines can be susceptible to developing issues with the following pests and diseases in the landscape: