Horticulture/Persicaria

Smartweeds are a group of plants in the genus Persicaria, which are usually encountered either as wildflowers or as weeds of lawns and gardens. The majority are annuals.

Description
Plants in this genus have swollen nodes and alternate, simple, spearhead-shaped leaves. The small flowers are held above the foliage on spikes, and are either pink or white. Flowers are borne from late spring through mid autumn, the seeds are likewise white or pink. Plants can be prostrate or bushy, depending on growing conditions and species.

Ecology
Smartweeds can be aggressive weeds of lawns and gardens, walkways, and patios, growing in both rich and poor soils.

Uses
Like buckwheat (which is closely related), the smartweeds can be used as a cover crop or green manure source, though self-seeding can become a nuisance if the plants are not mowed down before the seeds mature.

Some species and varieties are also grown as ornamental plants.