Verbena bonariensis is a summer stalwart with masses of lilac purple flowers on tall, see-through stems from midsummer until hard frost.

Verbena bonariensis 'Cloud 8' is a semi-dwarf selection of this summer stalwart with vivid purple flowers.

Vernonia angustifolia 'Plum Peachy' is a prairie ironweed topped with clusters of nectar-rich purple flowers on tall stems.

Spreading mats of variegated foliage with spires of pale blue flowers.

Veronica liwanensis has tiny, glossy, oval leaves that form a neat evergreen mat and cobalt blue flowers with a white central eye.

Veronica 'Goldwell' produces darling blue flowers with white eyes and lush groundcovering foliage.

Veronica incana 'Pure Silver' has gorgeous silver foliage and spires of royal purple flowers offering twice the interest of other speedwells.

Veronica 'Aspire' has short spires of glowing, deep rose flowers on this excellent Veronica.

Veronica 'Blue Skywalker' is a long blooming spike speedwell with a narrow form and tall flower spikes of lavender-blue.

Veronica 'Reavis' Crystal River has abundant blue flowers with white centres in spring with scattered rebloom.

Veronica 'Perfectly Picasso' is a long-blooming spike speedwell with spikes of white buds opening to pink flowers.

Veronica 'Snowmass' is a delicate yet vigorous creeping speedwell producing masses of pure white flowers with blue eyes

Veronicastrum virginicum 'Album' has white candelabras held aloft on tall stems with whorls of architectural foliage.

Veronicastrum virginicum 'Cupid' is a Culver's root with architectural lilac-blue blooms on tall rigid stems.

Veronica 'Tidal Pool' has darling blue flowers with white eyes and lush ground covering foliage.

Veronica 'Waterperry Blue' is a great evergreen speedwell with burgundy-flushed green foliage and charming lavender flowers.

Viola pedata 'Eco Artist Palette' is a bird foot violet with bi-coloured flowers in lilac-blue and purple atop dissected foliage.

Viola pedata is a lovely little violet with very cool, dissected foliage that looks like a bird's foot.

Viola walteri 'Silver Gem' is a fantastic trailing, ground-covering violet with silver foliage and reblooming purple flowers.

Viola x wittrockiana 'Bunny Ears' has unusual petals that resemble bunny ears in shades of pink, magenta, yellow, and white.

Viola 'Heartthrob' is a stunning violet with heart shaped leaves with rich burgundy centres and lavender flowers.

Weigela florida 'My Monet Purple Effect' is a dwarf ornamental shrub with tubular, pink-purple flowers and variegated foliage.

Weigela 'Afterglow' is a mid-sized ornamental shrub with funnel-shaped white and pink flowers atop dark foliage.