Pale smartweed is one of the largest smartweeds, often standing 2–6 ft (0.6–1.8 m) tall. Its long, drooping spikes of tiny white to pink flowers are the easiest way to recognize it. It grows in moist, open ground along ditches, ponds, and floodplains, and also in fields and waste ground. It is also called curlytop knotweed or nodding smartweed.
Appearance
- Growth form
- An annual with erect to spreading, densely branched stems that are often red and swollen just above each leaf joint.
- Leaves
- Lance-shaped leaves up to 8 in (20 cm) long, tapering to a sharp tip. Some have a dark blotch on top, but most do not. The papery sheath around the stem at each leaf base has few or no bristles at the rim.
- Flowers
- Dense, nodding spikes usually about 1¼–4 in (3–10 cm) long, greenish white to pink. Each flower is only about 1/8 in (3 mm) long.
- Flowering time
- July through September in Minnesota.
- Fruit
- A small, smooth, flattened seed about 1/8 in (3 mm) long, brown to black.
Look-alikes
Where it lives
- Typical habitats
- Ditches
- Shorelines and floodplains
- Fields
- Waste ground
- Range
- Found across both the Old and New Worlds, including many parts of the US, where native and introduced forms are both likely present. It is common throughout Minnesota.
- Preferred conditions
- Moist soil in full sun to part shade. It is a wetland plant that also grows in disturbed ground.
- Flowering
Flowers Jul–Sep
Flowers Jul–Sep
Name and classification
- About the name
- Formerly known as Polygonum lapathifolium. It is a highly variable species, and botanists have named many varieties and subspecies.
Conservation
- IUCN Red List
- LCLeast ConcernLow risk of extinction
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