Dioscorea polystachya
Common Name(s):
Previously known as:
- Dioscorea batatas
- Phonetic Spelling
- dy-oh-SCOR-ee-ah pol-ee-STAK-ee-uh
- This plant has low severity poison characteristics.
- See below
- Description
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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.
- See this plant in the following landscape:
- Cultivars / Varieties:
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- Tags:
- Cultivars / Varieties:
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- Tags:
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Attributes:
- Genus:
- Dioscorea
- Species:
- polystachya
- Family:
- Dioscoreaceae
- Uses (Ethnobotany):
- Many uses in Chinese medicine
- Life Cycle:
- Perennial
- Country Or Region Of Origin:
- Central & S. China to Kuril Islands and Taiwan
- Climbing Method:
- Twining
- Edibility:
- The tuber can be eaten raw or cooked but safest to cook the root
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Whole Plant Traits:
- Plant Type:
- Edible
- Herbaceous Perennial
- Poisonous
- Vegetable
- Vine
- Weed
- Woody Plant Leaf Characteristics:
- Deciduous
- Habit/Form:
- Climbing
- Growth Rate:
- Rapid
- Maintenance:
- High
- Texture:
- Medium
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Cultural Conditions:
- 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
- USDA Plant Hardiness Zone:
- 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
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Fruit:
- Fruit Type:
- Capsule
- Fruit Length:
- < 1 inch
- Fruit Width:
- < 1 inch
- Fruit Description:
- Seeds are winged and released from a capsule that splits open
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Flowers:
- Flower Color:
- White
- Flower Inflorescence:
- Insignificant
- Spike
- Flower Value To Gardener:
- Fragrant
- Flower Bloom Time:
- Summer
- Flower Size:
- < 1 inch
- Flower Description:
- Axillary clusters of small, white fragrant flowers with cinnamon fragrance in mid to late summer.
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Leaves:
- Woody Plant Leaf Characteristics:
- Deciduous
- Leaf Color:
- Green
- Leaf Feel:
- Glossy
- Leaf Type:
- Simple
- Leaf Arrangement:
- Opposite
- Leaf Shape:
- Cordate
- Leaf Margin:
- Lobed
- Hairs Present:
- No
- Leaf Length:
- 3-6 inches
- Leaf Width:
- 3-6 inches
- Leaf Description:
- 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.
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Stem:
- Stem Color:
- Green
- Purple/Lavender
- Stem Is Aromatic:
- No
- Stem Surface:
- Covered with a powdery bloom (glaucous)
- Stem Description:
- Twining often angled vine.
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Landscape:
- Problems:
- Contact Dermatitis
- Poisonous to Humans
- Weedy
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Poisonous to Humans:
- Poison Severity:
- Low
- 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.
- Poison Toxic Principle:
- Calcium oxalate crystals
- Causes Contact Dermatitis:
- Yes
- Poison Part:
- Roots
