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Chinese Yam

Dioscorea polystachya (dy-oh-SCOR-ee-ah pol-ee-STAK-ee-uh)

Family: Dioscoreaceae Non-native Vine (vertical)

Chinese Yam was introduced here as early as the 19th century for culinary and cultural uses and is now considered an invasive plant species in several states. It has spread from Louisiana to Vermont and can form dense masses of vines that cover and kill native vegetation, including trees, within a variety of moist, disturbed habitats. It spreads by seed, tubers and by the small tubers in leaf axils. It is a tuberous perennial vine that can grow to 11 feet or more and has long-stalked, glossy green heart-shaped leaves. It occasionally flowers in small axillary clusters. The elongated tuber grows 2-3 feet long and can be eaten raw or cooked. Prune to the ground in spring. Please choose a native vine instead. A few are listed to the left. Insects, Diseases, and Other Plant Problems: No significant problems in this country. However yams can be susceptible to fungal and viral diseases, scale, nematodes and mealybugs. This species is listed as invasive by the NC Invasive Plant Council.

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 58 attributes.

How it fits the guild

Guild layer 6 - Vine (vertical)
See companions & conflicts ↓

Companions & Conflicts

Curated pairwise relationships between this plant and others in the library — who feeds whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.

No curated interactions recorded for this species yet.

Also noted by NC State

Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.

Often confused with Dioscorea villosa
Fills a similar niche Lonicera japonica Lygodium japonicum Lygodium microphyllum
Similar, less problematic Ipomoea batatas

Full plant profile

Growing Conditions
Plant type
Edible; Herbaceous Perennial; Poisonous; Vegetable; Vine; Weed
Life cycle
Perennial
USDA zones
5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Light
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
High Organic Matter
Soil drainage
Good Drainage
Growth rate
Rapid
Maintenance
High
Canopy layer
6 - Vine (vertical)
Form & Appearance
Habit / form
Climbing
Texture
Medium
Foliage
Deciduous
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Opposite
Leaf shape
Cordate
Leaf margin
Lobed
Leaf feel
Glossy
Leaf size
3-6 inches long, 3-6 inches wide
Hairs present
No
Leaf detail
The leaves are up to 4.5 inches long and wide and are green and heart-shaped with 3 lobes. The arrangement is variable and may be alternately or oppositely arranged or borne in whorls. Warty round bulbils grow in the leaf axis from which new plants are formed.
Flower color
White
Flower value
Fragrant
Flower form
Insignificant; Spike
Flower size
< 1 inch
Flower detail
Axillary clusters of small, white fragrant flowers with cinnamon fragrance in mid to late summer.
Bloom time
Summer
Fruit type
Capsule
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Seeds are winged and released from a capsule that splits open
Stem color
Green; Purple/Lavender
Stem detail
Twining often angled vine.
Wildlife & Ecology
Native status
Non-native
Origin
Central & S. China to Kuril Islands and Taiwan
Food & Medicine
Edible parts
Roots; Tubers
Fruit type
Capsule

Edibility

The tuber can be eaten raw or cooked but safest to cook the root

Uses (ethnobotany)

Many uses in Chinese medicine

Landscape Use
Garden tags
#deciduous #poisonous #spring interest #heart-shaped leaves #moist soil #edible roots #sun #mat forming #aggressive #high maintenance #vine #weedy vine #weedy
Problems & Resistance
Insect problems
Mealybugs; Soft Scale Identification and Management on Ornamental Plants; Insect and Related Pests of Vegetables
Problems
Contact Dermatitis; Poisonous to Humans; Weedy
Poison severity
Low
Poison parts
Roots
Poison symptoms
Skin irritation from handling the uncooked tubers; irritation and burning of the mouth, lips, tongue and throat. It usually lasts a few minutes.
Toxic principle
Calcium oxalate crystals
Contact dermatitis
Yes
Toxicity summary
Low severity poison; parts: Roots; contact dermatitis

Planted at Hunnicutt

Nobody’s planted this one yet.