Viola 'Alice Witter' is a clump-forming herbaceous perennial in the Violaceae that carries evergreen to semi-evergreen foliage and produces blooms in both spring and autumn. It flowers in April, May and June, and again in September and October. The plant suits full sun or partial shade and tolerates a wide range of soils provided they remain moist but well drained. Its compact, clump-forming habit makes it straightforward to place at the front of borders or in containers.

Viola 'Alice Witter' is a clump-forming herbaceous perennial that flowers in April–June and September–October and suits sun or partial shade.

Viola 'Alice Witter' (Vt)

Viola 'Alice Witter'

Viola 'Leander' is a clump-forming herbaceous perennial in the Violaceae that flowers in April, May, June, September and October. It carries evergreen to semi‑evergreen foliage and performs in both full sun and partial shade. Plant in moist but well‑drained soil across a wide pH range on south-, west- or east-facing sites and expect a hardy (H5) plant habit.

Viola 'Leander' is a clump-forming perennial viola that flowers April, May, June, September and October and suits sunny or partially shaded sites.

Viola 'Leander' (Va)

Viola 'Leander' | Perennial Viola

Viola 'Panola Rose Picotee' (Panola Series) is a named cultivar in the genus Viola (family Violaceae) from the Panola series. It produces flowers in two main periods: April, May and June, and again in September and October. As a garden viola cultivar it is supplied for seasonal displays and should be planted following the supplier’s detailed care notes. Regular removal of spent flowers extends the display periods.

Viola 'Panola Rose Picotee' (Panola Series) is a Viola cultivar that flowers in April–June and September–October.

Viola 'Panola Rose Picotee' (Panola Series)

Viola 'Pearl Rose' is a named cultivar in the genus Viola (family Violaceae) notable for an extended flowering run. It blooms in April, May, June, September and October, giving both spring and autumn interest. Available from nurseries as a garden viola, it is handled and marketed alongside other named Viola varieties. The timed sequence of flowers makes it useful where repeat seasonal colour is wanted.

Viola 'Pearl Rose' is a named Viola cultivar that flowers in April, May, June, September and October.

Viola 'Pearl Rose'

Viola 'Pearl Rose' | April–June & Sept–Oct Flowers

Viola cornuta is a perennial in the Violaceae notable for its spring and autumn flowering. Native to the Pyrenees, it typically grows to around 0.2 m. It prefers full sun on sandy, loamy or clay soils that are moist but well-drained and is classed H6 (very hardy) in the UK; the flowers are scented.

Horned pansy (Viola cornuta) is a perennial flowering in April, May, June, September and October that prefers full sun and moist, well-drained soil.

https://en.wikipedia.org/wiki/Viola_cornuta

Viola cornuta

Horned pansy | Viola cornuta

Viola cornuta 'Alba' is a low-growing perennial that bears white horned violet flowers. It forms a compact clump to around 0.2 m and favours full sun on moist but well-drained sandy, loamy or clay soils. Native to the Pyrenees and northern Spain, it is rated H6 for UK hardiness (roughly USDA zones 6–11). Flowering occurs in April, May, June, September and October.

White Horned Violet Viola cornuta 'Alba' blooms in April–June and September–October and prefers full sun with moist, well-drained soil.

Viola cornuta 'Alba'

White Horned Violet | Viola cornuta 'Alba'

Viola cornuta 'Lilacina' is a low-growing perennial violet that produces pale violet flowers in two periods each year. It reaches around 0.2 m and suits sunny sites. Flowering occurs in April, May, June and again in September and October. It prefers moist but well-drained soils of sandy, loamy or clay types.

Violet Viola cornuta 'Lilacina' flowers in April–June and again in September–October and suits full sun with moist, well-drained soil.

Viola cornuta 'Lilacina'

Violet | Viola cornuta 'Lilacina'

Viola eizorensis is a species of Viola (family Violaceae) that produces flowers in April, May, June and again in September and October. It sits within the genus Viola and shows the herbaceous growth habit typical of violets. Flowers appear in two distinct periods, extending seasonal interest. Appropriate siting and soil care will help both flowering phases perform.

Viola eizorensis flowers in April–June and September–October and offers two seasonal displays for UK gardeners.

Viola eizorensis

Viola elatior is a perennial herb in the Violaceae that favours peat-rich fen soils. Native to Europe and western Asia, it grows where soils remain moist to wet and pH is acidic to neutral. The plant performs best in partial shade and flowers in April, May, June, September and October. Keep it in permanently damp, peaty conditions rather than drier borders.

Tall violet (Viola elatior) favours moist, peaty fen soils in partial shade and flowers in April–June and September–October.

https://en.wikipedia.org/wiki/Viola_elatior

Viola elatior

Tall violet | Viola elatior

Viola hastata is a clump-forming herbaceous perennial in the Violaceae notable for its halberd-shaped basal leaves. It bears yellow flowers in April, May, June, September and October. Foliage is evergreen to semi-evergreen, persisting through much of the year. It suits full sun or partial shade on moist but well-drained soils.

Halberd-Leaved Violet (Viola hastata) produces yellow flowers in April–June and September–October and prefers moist, well-drained soil in sun or part.

Viola hastata

Halberd-leaved violet | Viola hastata

Viola hispida is a clump-forming herbaceous perennial in the violet family that produces blooms in spring and again in autumn. Its foliage is evergreen to semi-evergreen, forming compact mats suitable for edges and containers. It tolerates full sun or partial shade and prefers moist but well-drained soils of chalk, clay, loam or sand. Hardiness H5 indicates it is classed as hardy in the UK.

Rouen pansy (Viola hispida) flowers in April, May, June and again in September and October and suits borders, containers and underplanting.

Viola hispida

Rouen pansy | Viola hispida

Viola rugulosa is a perennial violet in the family Violaceae that produces flowers in spring and again in early autumn. It is native to parts of Canada, including Alberta, British Columbia, Manitoba, Northwest Territories, Ontario, Saskatchewan and Yukon. Best sited where it receives partial shade and soil that stays moist yet drains freely. Flowering occurs in April, May, June, September and October.

Violet (Viola rugulosa) is a perennial native to Canada that flowers in April–June and September–October and prefers partial shade with moist.

Viola rugulosa

Violet | Viola rugulosa

Viola sororia 'Freckles' is a cultivar of Viola (family Violaceae) that produces purple flowers with white throats. It is a short-stemmed herbaceous perennial with glossy, heart-shaped leaves and a compact spread of 15–25 cm. In the UK it flowers in April, May, June, September and October. The plant readily self-seeds and may set cleistogamous seed heads in late summer and early autumn.

Common Blue Violet (Viola sororia 'Freckles') flowers in April, May, June, September and October and readily self-seeds in suitable sites.

Viola sororia 'Freckles'

Common Blue Violet | Viola sororia 'Freckles'

Viola verecunda var. yakusimana is a member of the genus Viola in the family Violaceae. It has recorded flowering months in April, May, June, September and October, giving both spring and autumn displays. Available information on this taxon is mainly taxonomic, so growers should check specialist references for detailed cultivation requirements. Note the flowering months when comparing plants for seasonal interest.

Viola verecunda var. yakusimana is a Viola (Violaceae) that flowers in April, May, June, September and October.

Viola verecunda var. yakusimana

Viola verecunda var. yakusimana | Spring & Autumn Blooms

Viola x wittrockiana 'Patiola Bronze Red' is a clump-forming herbaceous perennial in the Violaceae that flowers in April, May, June, September and October. It carries evergreen to semi-evergreen foliage and suits full sun or partial shade. The plant prefers moist but well-drained chalk, clay, loam or sandy soils across acid to alkaline pH. Use it in containers, borders or as an underplanting beneath roses and shrubs.

Viola x wittrockiana 'Patiola Bronze Red' is a clump-forming perennial for sun or partial shade that flowers in April, May, June, September and October.