T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Persicaria maculosa (Willow Weed)

Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Caryophyllales
Family: Polygonaceae
Genus:Persicaria .
Species: P. maculosa
Binomial name: Persicaria maculosa was Polygonum persicaria
Common name: Willow Weed, Redshank, Persicaria, Redleg, Lady's-thumb, Spotted Ladysthumb, Gambetta

Willow weed is native to Europe and Asia and is a perennial plant from the Knotweed family Polygonaceae. It is summer annual, dying off in late autumn. It usually grows less than 40cm tall and is commonly found throughout New Zealand during spring and summer. It thrives in cultivated land, well-aerated soils, banks and waste areas, and other moist locations. Crops and pasture can be suffocated at establishment due to its sprawling growth habit. Overseas reports indicate that digestion of willow weed has caused stock death, and some suspected poisoning in New Zealand has occurred.

As suggested by its name, the leaves of willow weed are similar in shape to those from willow trees. These leaves usually have a distinctive brown marking in their centre. At the base of each leaf, there is a papery sheath, a common characteristic of weeds in the Polygonaceae family. The round stems ( up to 80cm in length) often have a reddish tinge and are quite fleshy and, as mentioned above, can either be quite prostrate along the ground or grow fairly upright.. They lead off to a taproot.
Small pink flowers in an upright cylindrical shape are found at the tip of the stems. Leaves are dark green and sword shaped in dry conditions, but turn brownish green in wetter areas. It is killed by frosts.





Persicaria maculosa leaves with their distinctive brown marking in their centre.