| Scientific Name: | Persicaria maculosa ( syn. Polygonum persicaria ) |
| Common Name: | smartweed, lady's thumb |
| Family Name: | Polygonaceae |
| Origin: | Europe |
| Hardiness Zone: | Zone 1: (below -46 °C) |
| Plant Type: | Annual, Invasive plant, Weed (horticultural) |
| Mature Size: | 0.4 - 0.7m x 0.6 - 1.0m (height x width) |
| Habit: | Arching, Open, Spreading, Upright |
| Form: | Irregular, Oval - horizontal |
| Texture: | Medium |
| Landscape Uses: | Erosion control, Fall interest, Fragrance, Group or mass planting, Medicinal plant, Wetland - bogs |
| Exposure: | Full sun, Part sun/part shade, Filtered shade |
| Soil or Media: | Well-drained |
| Leaves: | Simple, Alternate, Soft flexible, Heavily veined, Pubescent, Lanceolate, Ciliate |
| Flowers: | Spike, White, Pink, Jul-Aug-Sep |
| Fruit: | Achene, Brown, Oct-Nov |
| Key ID Features: | |
| Erect reddish stems with swollen joints; leaves alternate, lanceolate, usually dark spotted, 3-10cm long; stipules fused into a stem-enclosing sheath that is loose and fringed with bristly hairs on top; inflorescence a dense spike, often nodding; achenes 2-3mm long, shiny and almost black. | |