Veronicastrum virginicum 'Challenger' is a Culver's root with architectural pale pink blooms on tall rigid stems.

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

Viola blanda is a darling violet with heart shaped leaves and fragrant, pure white flowers with deep purple veins on the lower petal.

Viola chaerophylloides 'Benizuru' has dissected leaves with fragrant, magenta and white flowers on red stems.

Viola corsica, the Corsican violet, offers masses of violet-blue flowers with purple whiskers and tiny yellow centres.

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 trailing, ground-covering violet with silver foliage and reblooming purple flowers.

Viola Starry Night gives us fragrant, dusky lavender blossoms with a yellow centre.

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

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.

Weigela 'Electric Love' is a dwarf ornamental shrub with tubular, red flowers and dark foliage.

Weigela 'Tuxedo' is a mid-sized ornamental shrub with fragrant, funnel-shaped, white flowers and dark foliage.

Wisteria frutescens 'Amethyst Falls' is a daintier, better behaved version of the Chinese wisteria for small spaces.

'Blue Moon' is an extremely fast growing and super hardy Wisteria for zone 3(!) that blooms up to three times a year.

Gordonia grandiflora is a remarkable semi-evergreen tree with lancolate leaves and fragrant, camellia-like flowers.

Yucca aloifolia "Magenta Magic" has evergreen stalks of deep green that deepen to purple mauve.

Yucca 'Bronze Age' is a blue-green yucca that has deep burgundy bronze colouration in fall and winter.

Yucca filamentosa 'Excalibur' forms rosettes of spiky, strap-like leaves coloured blue-green to powdery blue.

Yucca filamentosa 'Hofer's Blue' forms rosettes of spiky, strap-like leaves coloured in a bold silver-blue.

Zanthoxylum piperitum, the Japanese pepper, is an aromatic, spiny shrub with small, yellowish green flowers and scarlet fruits used in Japanese and Korean cooking.

Zanthoxylum simulans, the Sichuan pepper, produces brownish red fruits that are used in Sichuan cuisine having a spicy, numbing effect.

Zinnia grandiflora 'Gold on Blue' is hardy to zone 4 with fine, textured, bluish-green foliage topped with golden yellow flowers all summer.