Acanthus 'Morning Candle' is very free-flowering with extra tall and stately spires of mauve bracts and white flowers up to four feet tall.
Acanthus 'Whitewater' forms vigorous mounds of variegated foliage and pink stems holding white flowers.
Achillea ageratifolia is an unusual yarrow forming aromatic, silver-green, mounds covered in pure white daisies with light yellow centres.
Achillea Desert Eve Red has brick-red flowers above fragrant, fern-like foliage.
Achillea Desert Eve Terracotta has flowers in shades of yellow, orange and rusty orange.
Aconitum 'Blue Lagoon' is a dwarf monkshood with bright blue flowers.
Aconitum 'Spark's Variety' has four foot tall spikes of hooded, deep violet-blue monkshood flowers.
Aconitum 'Cloudy' is a gorgeous bicolour monkshood with blue and white flowers.
The tall stems and purple-blue flowers of the monkshood Aconitum 'Arendsii' offer a substitute for Delphinium for shadier conditions.
Aconitum 'Royal Flush' has spires of purple-blue monkshood flowers preceded by luscious chocolate-red new growth.
Aconitum fischeri is a shorter monkshood to two feet with purple-blue flowers.
Aconitum 'Album' has deeply cut ferny dark green leaves with bold white spikes of hooded monkshood flowers. Elegant.
Aconitum 'Rubellum' is a distinctly different monkshood with pretty pink flower spikes.
Aconitum napellus forms strong, vertical spires of purple-blue monkshood flowers.
'Stainless Steel' is a unique steely blue Aconitum that makes a great spike for sun or shadier conditions.
Actaea (Cimicifuga) 'White Pearl' has dissected green foliage and exceptionally long spires of fragrant white flowers in late summer.
Actaea 'Atropurpurea' is a tall bugbane with burgundy infused foliage and fragrant summer spires. Great for sun to part shade.
Actaea 'Brunette' great perennial with four foot spires of fragrant flowers above lush, ferny burgundy foliage. Great for sun to part shade.
Actaea pachypoda is a lovely and delicate woodlander and a perfect choice to create a quiet and relaxing vignette in the shade border.
Adiantum capillus-veneris is a dainty, delicate, beautiful fern with black stems that is magic in the shade garden.
Adiantum hispidulum forms delicate fronds that emerge pink against the previous year's dark green. A unique and gorgeous fern for the shade garden.
The evergreen Himalayan maidenhair fern, Adiantum venustum, forms delicate and elegant, slowly expanding mounds for the woodland garden.
Adiantum x mairisii is a delicate hybrid with black stems and lacy, bright green fronds. Sure to delight in the shade garden.
Adiantum x tracyi is a rare hybrid fern with black stems and lacy, bright green fronds. Sure to delight in the shade garden.
Agapanthus 'Back in Black' is a hardy lily-of-the-Nile with black stems, black buds, and dark purple-blue flowers followed by black seed pods.
Agapanthus 'Moonlight Star' has gorgeous and unique bicolour flowers of pale blue with dark violet blue stripes down the middle of each petal.
Agapanthus 'Polar Ice' is a cold hardy lily-of-the-Nile with pure white flowers.
Agapanthus 'Purple Cloud' is one of the darkest lily-of-the-Nile with rich, purple-blue, tubular flowers.
Agapanthus 'Twister' is a striking bicolour with rich blue and white flowers.