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Chinese Yam Dioscorea polystachya

Other 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

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:
Tags:
#deciduous#poisonous#high maintenance#moist soil#aggressive#edible roots#spring interest#weedy vine#vine#heart-shaped leaves#mat forming#weed#sun
 
Cultivars / Varieties:
Tags:
#deciduous#poisonous#high maintenance#moist soil#aggressive#edible roots#spring interest#weedy vine#vine#heart-shaped leaves#mat forming#weed#sun
  • 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
  • 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
  • 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
  • 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
  • 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.
  • 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.
  • Stem:
    Stem Color:
    Green
    Purple/Lavender
    Stem Is Aromatic:
    No
    Stem Surface:
    Covered with a powdery bloom (glaucous)
    Stem Description:
    Twining often angled vine.
  • Landscape:
    Problems:
    Contact Dermatitis
    Poisonous to Humans
    Weedy
  • 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