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Knotweed Polygonum

Other Common Name(s):

Phonetic Spelling
poh-lee-GON-um
Description

About 130 species of Knotweed or Smartweed are known, and most are plants of disturbed, moist areas. They vary greatly, can be annuals or perennials, and are mostly found in northern temperate areas of the world. Most are considered weedy. Native varieties tend to grow partially immersed in shallow waters of marshes, swamps, wet forests or ditches. The small flowers are generally in terminal spikes.

Ppensylvanicum and P. punctatum var. punctatum  are native to North Carolina.

 

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#full sun tolerant#white flowers#pink flowers#fall interest#high maintenance#NC native#summer flowers#wet soils tolerant#wet soils intolerant#perennial#weed#wildflower
 
Cultivars / Varieties:
Tags:
#full sun tolerant#white flowers#pink flowers#fall interest#high maintenance#NC native#summer flowers#wet soils tolerant#wet soils intolerant#perennial#weed#wildflower
  • Attributes:
    Genus:
    Polygonum
    Family:
    Polygonaceae
    Uses (Ethnobotany):
    Plants have been used in herbal medicine
    Life Cycle:
    Annual
    Perennial
    Recommended Propagation Strategy:
    Division
    Country Or Region Of Origin:
    Cosmopolitan
    Wildlife Value:
    Food and habitat source for fish and wildlife.
    Play Value:
    Wildlife Cover/Habitat
    Wildlife Food Source
  • Whole Plant Traits:
    Plant Type:
    Annual
    Native Plant
    Perennial
    Weed
    Habit/Form:
    Spreading
    Growth Rate:
    Rapid
    Maintenance:
    High
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Soil Drainage:
    Moist
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a
  • Fruit:
    Fruit Color:
    Black
    Brown/Copper
    Cream/Tan
    Red/Burgundy
    Fruit Type:
    Capsule
    Fruit Description:
    3-sided capsule is tan to reddish-brown to black in color with 1 seed.
  • Flowers:
    Flower Color:
    Pink
    White
    Flower Inflorescence:
    Spike
    Flower Bloom Time:
    Fall
    Summer
    Flower Description:
    Small blooms from late summer to early fall that grow on terminal spikes. Varies as per species.
  • Leaves:
    Leaf Color:
    Green
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Lanceolate
    Linear
    Hairs Present:
    No
    Leaf Description:
    Leaves are lance-shaped, narrow and willow-like. The leaf bases form a sheath around the stem. Varies as per species.
  • Stem:
    Stem Is Aromatic:
    No
  • Landscape:
    Landscape Theme:
    Native Garden
    Resistance To Challenges:
    Wet Soil
    Problems:
    Weedy