Pale Knotweed- a native (Persicaria lapathifolia).

Other names: Pink Knotweed.

Family: Polygonaceae (Knotweed family). Cosmopolitan.

Native of Australia, Europe, Asia and northern Africa.

Occurrence: Grows beside streams, and the margins of swamps and lakes. It may be locally abundant.

Identification:

• it grows in damp areas
• it is taller than the other knotweeds, growing to a metre or more
• the flowers are pink or greenish-pink, and grow in a long narrow cylindrical cluster
• the leaves are broad, and often have a brown blotch
• there are sheaths at the base of the leaves which surround the stem; the sheaths do not have bristles.

Pale Knotweed is an annual or biennial. Occasionally the leaves and stems have dense cottony hairs.

Similar species: Slender Knotweed is similar in appearance. It does not grow as high (to about 50 cm), and the sheaths at the leaf-bases are bristly.

There are three knotweeds common in the district. All grow in wet areas e.g.mud-flats, beside streams etc..
Creeping Knotweed (Persicaria prostrata). Prostrate plant. Sheaths at leaf bases develop a green leaf at the tip.
Slender Knotweed (Persicaria decipiens). Spreading or erect. Sheaths at leaf bases end in stiff hairs.
Pale Knotweed (Persicaria lapathifolia). Erect plant tp 1 metre or more. Sheaths at base of leaves summit often torn, not ending in hairs.

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