Achillea ‘Lachsschönheit’

Feathery foliage and large, flat heads of salmon-pink flowers (the plant is also seen labelled Salmon Beauty) make this clump-forming perennial a good choice to grow with wild flowers or in a mixed border. It is one of the Galaxy Hybrids series, which offers a wide range of colors. Height 30–36 in (75–90 cm) – Width 24 in (60 cm)

Achillea ‘Taygetea’

Large, creamy-yellow flowerheads appear in summer and fall, providing perfect landing pads for summer-visiting insects looking for a source of nectar. Finely-cut, grayish-green leaves appear along the length of the stems, acting as a contrasting foil to the flowers. Height 24 in (60 cm) – Width 18 in (45 cm)

Agapanthus Headbourne Hybrids

These plants were first raised by the Hon. Lewis Palmer in his Hampshire, England garden, using South African seed. The resulting hybrids have larger flowers than most African lilies, and are hardier. Grow in a mixed border or in pots. Height 24–36 in (60–90 cm) – Width 36 in (90 cm)

Anaphalis triplinervis

These are easy garden plants to grow and are very effective in a border where the emphasis is on white and silver. The clusters of flowers, borne from mid- to late summer, have papery white bracts, and make good cut flowers. Height 32–36 in (80–90 cm) – Width 18–24 in (45–60 cm)

Aquilegia vulgaris ‘William Guiness’

There are many granny’s bonnets to choose from, but the exquisite colors of ‘William Guiness’ (here shown against a background of hosta leaves) make it a popular choice. Tall flower stems are carried above divided leaves; the plants are suited to cottage gardens or mixed borders. Height 36 in (90 cm) – Width 18 in (45 cm)

Asplenium scolopendrium Crispum Group

The Hart’s tongue fern is evergreen, with wavy-edged fronds, making it a year-round decorative asset in the garden. For the lushest plants, choose a position in dappled shade with moist, rich soil to prevent sun scorching. A mixed woodland border would be ideal. Height 12–24 in (30–60 cm) – Width 24 in (60 cm)

Astelia chathamica

Dense clumps of arching, silver scaly leaves make this an attractive plant for a border or container. Pale yellowish-green flowers appear on long stalks from mid- to late spring, followed, on female plants, by orange berries. Do not allow roots to become over-wet during the winter months. Height 4 ft (1.2 m) – Width to 6 ft (2 m)

Aster ericoides ‘White Heather’

A reliable and easy-to-grow perennial, ‘White Heather’ produces sprays of small daisy blooms at the end of summer, prolonging the season of interest in the garden. A sunny site will ensure an extended spell of flowering. To increase the stock, divide larger plants in spring. Height 3 ft (1 m) – Width 12 in (30 cm)

Aster novae-angliae ‘Andenken an Alma Pötschke’

A favorite with gardeners, the New England asters rarely fail to live up to expectations. Rich cerise-pink blooms are borne in profusion from late summer to mid-fall. Mix varieties together to create your own aster display or plant among other perennials for late summer color. Height 4 ft (1.2 m) – Width 24 in (60 cm)

Astrantia ‘Hadspen Blood’

Astrantias are well-suited to areas of dappled shade in the garden. The cultivar ‘Hadspen Blood’ is clump-forming, with deeply cut, mid-green leaves and clusters of dark red flowers surrounded by equally dark red bracts. The flowers can be dried for winter flower arrangements. Height 12–36 in (30–90 cm) – Width 18 in (45 cm)

Astrantia major ‘Sunningdale Variegated’

This astrantia is remarkable for its leaves, which are unevenly margined with soft yellow and cream. Although the pale pink flowers are attractive, the foliage is the main feature. Trim back the leaves to encourage new growth and choose a sunny site for best variegation. Height 12–36 in (30–90 cm) – Width 18 in (45 cm)

Campanula ‘Burghaltii’

In midsummer, pendent, lavender-colored bells, opening from blue-purple buds, dangle from the stems of this mound-forming perennial, against a background of heart-shaped leaves. The plant prefers neutral to alkaline conditions to thrive. Alternatively, grow it in a large container. Height 24 in (60 cm) – Width 12 in (30 cm)

Campanula glomerata ‘Superba’

The erect stems of this bellflower bear clusters of deep purple, bell-shaped flowers throughout the summer. Prolong the flowering season by cutting plants back to the top of the leaves after the first flush of blooms. This variety is vigorous and can even be invasive. Height 24 in (60 cm) – Width indefinite

Centaurea dealbata ‘Steenbergii’

Tolerant of dry conditions, knapweed is a magnet for bees and butterflies. The rich pink flowers with feathery petals can be cut for indoor displays when they appear in summer. The plant looks attractive in wild parts of the yard, or as part of a cottage garden plan. Height 24 in (60 cm) – Width 24 in (60 cm)

Clematis integrifolia

This herbaceous perennial carries flowers on the current year’s shoots, from midsummer to late fall. The mid-blue flowers have slightly twisted ‘petals’ and cream anthers, and are followed by silvery seedheads which provide an extended season of interest. The plant may need supporting. Height24 in (60 cm) – Width 24 in (60 cm)

Clematis tubulosa ’Wyevale’

This clematis grows as a freestanding shrub. The late summer flowers are pale blue, scented, and are produced in clusters, resembling hyacinth blooms. Fluffy, silvery seedheads follow, which are also decorative. The plant prefers a chalky soil in full sun or part shade. Height 2½–4½ ft (75–130 cm) – Width 3 ft (1 m)

Dicentra spectabilis ‘Alba’

When in flower, the graceful, arching stems of the bleeding heart (or Dutchman’s breeches) look like a miniature washing line. New shoots appear in spring with rose-pink or white flowers. ‘Alba’ is a less vigorous selection with pure white blooms. It will tolerate some sun if the roots are kept moist. Height to 4 ft (1.2 m) – Width 18 in (45 cm)

Digitalis grandiflora

The yellow foxglove forms sturdy, imposing clumps of tall flower spikes with glossy leaves, and is best sited where it will make an impact. Large, tubular flowers with speckled throats radiate outwards. Choose dappled shade under trees or a sheltered part of the yard for best results. Height to 3 ft (1 m) – Width 18 in (45 cm)

Digitalis x mertonensis

This cross between the yellow foxglove and common foxglove has resulted in a free-flowering perennial bearing large pink tubular flowers in late spring and early summer. An excellent plant for attracting bees. Self-sown seedlings will appear around the parent plant. Height to 36 in (90 cm) – Width 12 in (30 cm)

Dryopteris erythrosora

This slowly spreading fern from China and Japan emerges from the soil as coppery-red young fronds. These gradually turn pink and then silvery-green with age, forming a lacy network over the ground. Keep soil around the roots moist and site in a sheltered area. It makes a striking plant for a border. Height 24 in (60 cm) – Width 16 in (40 cm)

Echinacea ‘Art’s Pride’

The narrow orange petals of this coneflower surround a prominent, rust-colored, cone-shaped disc which appeals to all kinds of insects. Flowers are also slightly scented. Grow in a mixed border, or wildlife or cottage garden. With their sturdy stems, echinaceas also make good cut flowers. Height 24–36 in (60–90 cm) – Width 18 in (45 cm)

Echinacea purpurea ‘Alba’

This is the white version of the popular, purple-flowered Echinacea purpurea. Large, reflexed, white petals surround a central yellow cone on long flower stems, from midsummer to fall. These plants work well with grasses and slimstemmed perennials, such as Verbena bonariensis. Height to 5 ft (1.5 m) – Width 18 in (45 cm)

Eremurus stenophyllus

The lovely tapering flower spikes of foxtail lilies emerge and bloom in summer. Staking may be required to prevent the tall stems blowing over. Provide a site with free-draining soil, and mulch around the crowns with garden compost in the fall. Suited to the back of a garden border. Height 3 ft (1 m) – Width 24 in (60 cm)

Euphorbia griffithii ‘Dixter’

This is a striking herbaceous perennial that contrasts well with other green-leaved euphorbias. Its copper-tinted, dark green leaves make an effective background to the orange bracts that surround the inconspicuous true flowers. The best color comes from plants grown in dappled shade. Height 30 in (75 cm) – Width 3 ft (1 m)

Euphorbia x martini

With unusual flowers in a mixture of greens and reds, produced on the previous year’s shoots, this euphorbia would be a welcome addition to any yard. It flowers over a long season from spring to midsummer and is a very adaptable plant, tolerating sun and shade. Height 3 ft (1 m) – Width 3 ft (1 m)

Euphorbia schillingii

Pale yellow flowerheads perch above a mass of wiry, leafy  stems on this strong-growing herbaceous perennial. Plant it with other border perennials, choosing colors carefully to bring out the subtleties of this late summer- to fall-flowering plant. Provide rich soil in dappled shade. Height 3 ft (1 m) – Width 12 in (30 cm)

Geranium ‘Brookside’

This densely growing perennial is ideal for border edges; it is a vigorous, spreading plant and makes attractive ground cover, for sun or part-shade. Abundant violet-blue flowers with pale centers appear in summer, held above a mass of finely divided green leaves. Height 24 in (60 cm) – Width 18 in (45 cm)

Geranium macrorrhizum

This plant has strongly aromatic, toothed, sticky leaves that turn an attractive red in the fall. Clusters of flat pink flowers with protruding stamens are borne in early summer from a mass of sprawling stems. This is a good plant for ground cover or underplanting in a shady site. Height 20 in (50 cm) – Width 24 in (60 cm)

Geranium ‘Nimbus’

A very vigorous and floriferous geranium that becomes a sea of blue when the lavender-blue flowers appear in summer. This plant is very tolerant of shade and is a good choice for darker borders or corners that receive little direct sunlight. Clip to encourage repeat flowering. Height to 3 ft (1 m) – Width 18 in (45 cm)

Geranium phaeum

The dusky cranesbill is undemanding in its garden requirements. It will tolerate sun but is also a useful plant for deep shade. Dark maroon flowers with white eyes are produced in early summer. For a brighter-flowered geranium, try G. psilostemon, with its black-centered magenta flowers. Height 32 in (80 cm) – Width 18 in (45 cm)

Helenium ‘Moerheim Beauty’

Copper-red daisy flowers, each with a distinctive round central disc, are borne in early to late summer, filling the garden with warm color. Deadhead through the season to encourage repeat flowering. The plant’s striking color and form mix well with either hot colors or pastel shades. Height 36 in (90 cm) – Width 24 in (60 cm)

Helleborus argutifolius

The Corsican hellebore is a valuable plant for the designer in search of winter interest. A glossy-leaved perennial, it comes into flower in late winter and early spring, and the blooms are an unexpected pale green. It grows well in most conditions but will not thrive in acid soils. Height to 4 ft (1.2 m) – Width 36 in (90 cm)

Helleborus foetidus

The stinking hellebore is named for the unpleasant smell its leaves give off when crushed. However, the greenish-white flowers the plant bears in midwinter and early spring make up for this downside. Other good varieties to choose from include the Wester Flisk Group, with red-tinted main stems. Height to 32 in (80 cm) – Width 18 in (45 cm)

Hemerocallis ‘Buzz Bomb’

Originally bred in 1961, this brightly colored daylily is a strong grower, flowering in midsummer. The large, orange-red blooms with yellow throats are carried above strap-like green leaves over a long season. Grow in a mixed or herbaceous border in full sun for maximum effect. Height 24 in (60 cm) – Width 24 in (60 cm)

Hemerocallis ‘Marion Vaughn’

A late afternoon-flowering daylily, ‘Marion Vaughn’ is a dependable evergreen with clear lemon-yellow flowers and bright green strap-like foliage, making a crisp addition to a mixed border. It looks good growing in a drift with other daylilies. Full sun will promote best flowering. Height 34 in (85 cm) – Width 30 in (75 cm)

Hosta ‘Francee’

Hostas are shade-loving foliage plants and versatile in the garden, suited to ground cover, containers, a woodland garden or mixed border. Olive-green heart-shaped leaves with a variable white margin make ‘Francee’ a popular choice. Lavender-blue flowers emerge in summer. Height 22–28 in (55–70 cm) – Width 3 ft (1 m)

Hosta ‘Royal Standard’

This clump-forming perennial does well in shade but will also tolerate some sun. Its unmarked pale green leaves have prominent ribs and provide an excellent foil for the funnel-shaped, fragrant white flowers that appear in late summer. It is fast-growing and vigorous. Height 24 in (60 cm) – Width 4 ft (1.2 m)

Hosta sieboldiana var. elegans

With its heavily puckered, blue-green leaves, this large hosta makes a dramatic border plant. It tolerates shade although a very dark position will subdue the production of lilac-colored flowers in early summer. Place a group of hostas together for a stunning foliage effect. Height 3 ft (1 m) Width 4 ft (1.2 m)