Eriogonum grande var. rub. (dark form) is a mat-forming perennial in the Polygonaceae, notable for its tall, stout flowering stems that rise above a basal rosette of leaves. Flower clusters may be white, pink or red and appear from June to September. Leaves are borne mainly at the base, with wavy margins and reach up to 10 centimetres in length. The plant combines a low vegetative habit with conspicuous, upright inflorescences.

Redflower Buckwheat (Eriogonum grande var. rub. (dark form)) forms a low perennial mat and flowers from June to September.

Eriogonum grande var. rub. (dark form)

Redflower Buckwheat | Eriogonum grande var. rub. (dark form)

Persicaria affinis 'Superba' is a mat-forming perennial in the Polygonaceae that forms dense clumps roughly 25 cm high and 60 cm across. It bears cylindrical spikes of pale pink to rose-red flowers from June to August. Leaves are produced mainly at ground level, creating a close carpet beneath the flowering stems.

Persicaria affinis 'Superba' is a mat-forming perennial that flowers from June to August.

Bistorta is a genus of flowering plants in the family Polygonaceae. As of February 2019 about 40 species are accepted.

Persicaria affinis 'Superba'

Himalayan Bistort | Persicaria affinis 'Superba'

Persicaria amp. 'Blackfield' is a cultivated member of the Persicaria genus in the knotweed family, Polygonaceae. As a Persicaria it produces the genus's characteristic flowering spikes and blooms in the UK from July to September. Plants in this genus are herbaceous, with stems and alternately arranged leaves, and may develop from taproots, fibrous roots, rhizomes or stolons. The inflorescences may be arranged as panicles, spikes or compact heads.

Persicaria amp. 'Blackfield' is a Persicaria cultivar that flowers in the UK from July to September and carries the genus's spiked inflorescences.

Persicaria is a genus of herbaceous flowering plants in the knotweed family, Polygonaceae. Plants of the genus are known commonly as knotweeds or smartweeds.

Persicaria amp. 'Blackfield'

Persicaria amp. 'Taurus' is a Persicaria in the knotweed family (Polygonaceae) noted for its summer flowering, which runs from July to September. As a member of the genus Persicaria it is herbaceous and shares the group’s range of root and stem habits, from taproots to rhizomes and stolons. Flowers are carried in spike- or panicle-like inflorescences typical of the genus. Expect a plant whose seasonal bloom period provides a clear summer presence in the border.

Persicaria amp. 'Taurus' is a Persicaria (Polygonaceae) that flowers from July to September.

Persicaria amp. 'Taurus

Knotweed | Persicaria amp. 'Taurus

Persicaria amplex. 'Alba' is a member of the Persicaria genus in the Polygonaceae (knotweed) family, valued for its summer display. As with other Persicaria, plants are herbaceous and may show a range of growth habits within the genus. Expect flowering from July to September.

Persicaria amplex. 'Alba' flowers from July to September and belongs to the Polygonaceae family.

Persicaria amplex. 'Alba'

Knotweed | Persicaria amplex. 'Alba'

Persicaria amplex. 'Blackfield' is a cultivar of Persicaria in the knotweed family Polygonaceae, notable for its summer flowering from July to September. It belongs to a genus of herbaceous plants that can be annual or perennial and shows a variety of stem and root habits. Flowers in Persicaria are carried in spikes, panicles or headlike clusters and may range in colour within the genus. The genus often bears a papery ochrea at the leaf nodes.

Persicaria amplex. 'Blackfield' is a Persicaria (Polygonaceae) cultivar that flowers from July to September and benefits from cutting back after flowering.

Persicaria amplex. 'Blackfield'

Knotweed | Persicaria amplex. 'Blackfield'

Persicaria amplex. 'Taurus' is a cultivated form of Persicaria in the knotweed family Polygonaceae, producing spikelike clusters of small flowers. Members of the genus carry flowers that can range from white and greenish through to pink, red and purple; this cultivar flowers in the UK from July to September. The group shows variable root and stem habits, so check the supplier for precise habit and spread.

Persicaria amplex. 'Taurus' is a Persicaria cultivar that produces spikelike flower clusters in the UK from July to September.

Persicaria amplex. 'Taurus'

Knotweed | Persicaria amplex. 'Taurus'

Persicaria rucinata 'Needham's Form' is a cultivar of Persicaria in the knotweed family Polygonaceae. Persicaria comprises herbaceous species commonly referred to as knotweeds or smartweeds, with diverse stem and leaf forms. This cultivar produces flowers from July to September. Consult the supplier for specific notes on flower and foliage appearance.

Persicaria rucinata 'Needham's Form' is a Persicaria cultivar that flowers from July to September.

Persicaria rucinata 'Needham's Form'

Polygonum albinum is a perennial in the knotweed family that can grow as a mat-forming ground cover, a clump, or as tall upright stems. It has deciduous, simple leaves that range from lance-shaped to heart-shaped and are often marked or take an autumn tint. Flowering occurs from July to September. Plants tolerate a wide range of soils, including heavy clay, and are suited to full sun or partial shade.

Knotweed (Polygonum albinum) is a perennial Polygonaceae species flowering July to September that tolerates full sun to partial shade and most soils.

The knotweeds are vigorous, long-flowering plants carrying dense narrow spikes or loose sprays of tiny flowers, usually in pink, crimson or greenish white, above simple lance-shaped or heart-shaped foliage that frequently colours well in autumn. Habit varies enormously, from low creeping mats that make dense weed-suppressing cover to tall, architectural clump-formers. Several are extremely vigorous, and the genus has been extensively reclassified, with many garden plants now placed in Persicaria.

Polygonum albinum

Knotweed | Polygonum albinum

Polygonum carneum is a perennial in the buckwheat family (Polygonaceae) that can grow as a mat-forming ground cover, clump, or a taller upright plant. It has deciduous, simple leaves that range from lance-shaped to heart-shaped and may be marked or take on autumn tints. Flowering occurs from July to September. It suits a wide range of positions and soils, and prefers reliably moist conditions.

Knotweed (Polygonum carneum) flowers from July to September and suits moist, any-soil sites in full sun or partial shade.

Polygonum carneum

Knotweed | Polygonum carneum

Polygonum equisetiforme is a perennial knotweed that can form mats, clumps or grow upright to about 1.0 m. It has deciduous, simple leaves that range from lance-shaped to heart-shaped and are often marked or take on autumn tints. Flowering occurs July to September. It suits a wide range of sites, including heavy clay and damp ground.

Knotweed (Polygonum equisetiforme) is a perennial from Portugal that reaches about 1.0 m and flowers July to September.

Polygonum equisetiforme

Knotweed | Polygonum equisetiforme

Polygonum milletii is a perennial member of the buckwheat family (Polygonaceae) that can grow as a mat-forming ground cover, clump-forming plant or as a taller upright perennial. The leaves are deciduous, simple and range from lance-shaped to heart-shaped, often showing markings or autumn tint. It flowers from July to September. It tolerates a wide range of soils, including heavy clay, and prefers moist conditions.

Polygonum milletii is a perennial knotweed that flowers July to September and suits moist soil in full sun to partial shade.

Polygonum milletii

Knotweed | Polygonum milletii

Polygonum paniculatum is a perennial member of the buckwheat family (Polygonaceae) with a notably variable habit: it may be mat-forming, clump-forming or grow tall and upright. Leaves are deciduous, simple and range from lance-shaped to heart-shaped, often marked or taking on autumn tint. It prefers full sun to partial shade and tolerates almost any soil, including heavy clay, as long as the ground remains reasonably moist. Flowers are produced from July to September.

Knotweed (Polygonum paniculatum) is a perennial that flowers from July to September and tolerates moist soil and heavy clay.

Polygonum paniculatum

Knotweed | Polygonum paniculatum

Polygonum regelianum is a perennial knotweed that shows a notably variable habit, from mat-forming and clump-forming to taller, upright growth. Its deciduous leaves are simple, lance-shaped to heart-shaped and are often marked or take on autumn tints before falling. Flowering occurs July to September. It tolerates a wide range of soils, including heavy clay, and prefers reliably moist conditions over drought.

Knotweed (Polygonum regelianum) is a perennial with variable habit that flowers July to September and suits moist soils in full sun to partial shade.

Polygonum regelianum

Knotweed | Polygonum regelianum

Polygonum rude is a perennial in the knotweed family with a variable habit that can be mat-forming, clump-forming or tall and upright. The foliage is deciduous, simple and ranges from lance-shaped to heart-shaped, often marked or taking on autumn tints. It flowers from July to September. Plants tolerate almost any soil, including heavy clay, and prefer moist conditions in full sun to partial shade.

Knotweed (Polygonum rude) is a deciduous perennial that flowers July to September and thrives in moist soils, tolerating heavy clay in sun or part shade.

Polygonum rude

Knotweed | Polygonum rude

Polygonum ussuriense is a perennial knotweed that can be mat-forming, clump-forming or grow tall and upright. Its deciduous leaves are simple, lance- to heart-shaped and are often marked or take on autumn tint. Flowering in the UK occurs from July to September. It tolerates full sun to partial shade and will grow in almost any soil, including heavy clay, provided the ground stays reasonably moist.

Knotweed (Polygonum ussuriense) is a deciduous perennial from northeast Asia that flowers July to September and tolerates heavy clay and moist ground.

Polygonum ussuriense

Knotweed | Polygonum ussuriense

Rheum alexandrae is a perennial in the knotweed family (Polygonaceae) valued for ornamental use in borders and water gardens. It originates from south-west China and flowers in the UK from June to July. Planting and handling require care because all parts are harmful if eaten; wear gloves and protective equipment when working with it.

Alexander's rhubarb (Rheum alexandrae) is a perennial for partial shade and moist, acidic to neutral soils, flowering in the UK from June to July.