Polygonum capitatum – Pinkhead Smartweed

Polygonum capitatum - Pinkhead Smartweed, Pinkhead Knotweed, Pink Knotweed

Polygonum capitatum - Pinkhead Smartweed, Pinkhead Knotweed, Pink Knotweed

Polygonum capitatum - Pinkhead Smartweed, Pinkhead Knotweed, Pink Knotweed

Polygonum capitatum - Pinkhead Smartweed, Pinkhead Knotweed, Pink Knotweed (stressed plant with red leaves)

Polygonum capitatum - Pinkhead Smartweed, Pinkhead Knotweed, Pink Knotweed

Plant Name

Scientific Name: Polygonum capitatum

Synonym: Persicaria capitata

Common Names: Pinkhead Smartweed, Pinkhead Knotweed, Pink Knotweed

Plant Characteristics

Duration: Perennial

Growth Habit: Subshrub, Herb/Forb

Hawaii Native Status: Introduced. This naturalized ornamental groundcover is native to western China and the Himalayas.

Flower Color: Medium pink to whitish pink

Height: Stems up to 20 inches (50 cm) long

Description: The tiny flowers are clustered in ball-shaped or head-shaped flower spikes above the foliage. The leaves are alternate, green to tinged red or purple, edged with dark red, marked with a distinctive v-shaped dark band, and ovate to elliptic in shape. The leaves on stressed plants can turn bright red. The plants are mat-forming and have prostrate stems that can root at the nodes.

On the Big Island of Hawaii, these weedy plants grow along roadsides and in open lava fields at middle elevations.

Classification

Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Subclass: Caryophyllidae
Order: Polygonales
Family: Polygonaceae – Buckwheat family
Genus: Polygonum L. – knotweed
Species: Polygonum capitatum Buch.-Ham. ex D. Don – pinkhead smartweed

More About This Plant

Hawaii County Distribution Map