Acaena inermis 'Purpurea' is an excellent ground cover for crawling over gravel paths or stones with gorgeous purple-blue-grey foliage.

Acaena saccaticupula 'Blue Haze' is an excellent ground cover with powder blue foliage.

Acanthus 'Whitewater' forms vigorous mounds of variegated foliage and pink stems holding white flowers.

Achillea 'Apricot Delight' has large, flat-topped flower clusters in various shades of pink on strong stems up to 24 inches with fragrant, fern-like foliage.

Achillea millefolium 'New Vintage Red' has large, flat-topped flower clusters of bright red with white centres.

Achillea millefolium 'New Vintage Rose' has large, flat-topped flower clusters of rose pink with white eyes on strong stems to 24 inches.

Achillea millefolium 'New Vintage Violet' has large, flat-topped flower clusters of bright lavender pink with white centres.

Achillea millefolium, the common yarrow, is an important nectar source and host plant for a diversity of insects.

Achillea ptarmica 'Peter Cottontail' is a unique yarrow with white, button-like flowers held in low, cloud-like mounds.

Achimenes 'Blue Sparks' is an orchid pansy related to the African violet with delicate white to lavender/blue tubular blooms.

Achimenes 'Cattleya' is an orchid pansy related to the African Violet with delicate violet-blue tubular blooms and lighter throats.

Achimenes 'Charm' is an orchid pansy related to the African Violet with delicate rosy-pink tubular blooms.

Achimenes 'Harry Williams' has beautiful pansy-shaped flowers that emerge crimson red then morph to crimson violet.

Achimenes 'Peach Blossom' is an orchid pansy related to the African Violet with delicate light pink tubular blooms and magenta throats.

Achimenes 'Snow Princess' is an orchid pansy related to the African Violet with delicate snow white blooms and tiny purple throats.

Peacock gladiolus (Acidanthera murielae) is topped in summer with large, white, fragrant flowers with purple-black centres.

Aconitum 'Cloudy' is a gorgeous bicolour monkshood with blue and white flowers.

Aconitum 'Rubellum' is a distinctly different monkshood with pretty pink flower spikes.

Actaea japonica 'Silver Blush' has has wands of creamy-white bottle brush flowers and serrated silver foliage maturing to green.

Actaea japonica 'Silver Dance' is has wands of creamy-white bottle brush flowers and silver foliage maturing to green.

Actaea (Cimicifuga) 'White Pearl' has dissected green foliage and exceptionally long spires of fragrant white flowers in late summer.

Actaea pachypoda 'Misty Blue' is a white baneberry with bluish foliage and white flowers followed by white fruit with a black dot.

Adenophora 'Gaudi Violet' is a beautiful bellflower relative with elegant spikes of light violet bell-shaped flowers.

Adiantum hispidulum forms delicate fronds that emerge pink against the previous year's dark green. A unique and gorgeous fern for the shade garden.

Adiantum pedatum, the northern Maidenhair fern, is one of the most beautiful of all ferns with distinctive palmate fronds.

Adiantum raddianum 'Fragrantissimum' is an evergreen maidenhair fern with arching black stems and light green aromatic fronds.

The evergreen Himalayan maidenhair fern, Adiantum venustum, forms delicate and elegant, slowly expanding mats.

Adiantum x mairisii is a delicate hybrid with black stems and lacy, bright green fronds. Sure to delight in the shade garden.

Agapanthus 'Galaxy Blue' has large umbels of royal blue, trumpet-shaped blossoms. Hardy to zone 6!

Agapanthus 'Galaxy White' has five inch wide umbels of white, trumpet-shaped blossoms on tall stems. Hardy to zone 6!