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

Achillea ageratifolia is an unusual yarrow forming aromatic, silver-green, mounds covered in pure white daisies with light yellow centres.

Achillea filipendulina ‘Gold Plate’ is a yarrow that produces masses of large golden-yellow flowers on tall stems.

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

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 Desert Eve 'Deep Rose' is a yarrow with dark pink flowers with yellow centres above fragrant, fern-like foliage.

Achillea Desert Eve 'Red Improved' has brick-red flowers above fragrant, fern-like foliage.

Achillea Desert Eve Terracotta has flowers in shades of yellow, orange and rusty orange.

Achillea millefolium 'Heartthrob' has large, flat-topped flower clusters with colourfast, velvet-red flowers above dissected, 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 'Sassy Summer Taffy' has large, flat-topped flower clusters in shades of deep rose pink, salmon pink, light pink, and peachy pink on tall, strong stems to 32 inches

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

Achlys triphylla is a unique ground cover attractive to pollinators and hummingbirds. The dried three-part leaves smell like vanilla.

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.

Japanese monkshood, Aconitum japonicum, has wonderful, hooded purple-blue flowers in summer on arching stems.

Aconitum lamarckii (syn. pyrenaicum) is an unusual monkshood with long airy racemes of pale sulphur yellow tubular flowers.