Carrying the cool palette through autumn
The soft range of the cool palette drifts toward romantic combinations of violet, pale blue, mauve and pink, such as the icy pink ‘Sarah Bernhardt' peony, a scented double flower of slightly fringed, shell pink petals with silver highlights, which works well against the canes of the species redleaf rose. Its dark, reddish purple leaves provide a subtly cool counterpoint all season.
For other border partners, the perennial cornflower ‘John Coutts', with its finely cut, greyish green foliage and clear magenta-pink flowers, will be happy next to ‘Butterfly Blue' dwarf pincushion flower, offering a long season of soft blue bloom. Add in the dreamy (and mildew-resistant) ‘Franz Schubert' phlox, with its moody, lilac-blue flowers and the emphasis of a darker eye; and the palest porcelain blue ‘Chettle Charm' peachleaf bell-flower, with a fine line of violet along each bell rim. Complete the summer show with two mid-season daylilies, such as the big, ruffled, pure ivory blossoms of ‘Innocent Bystander' (flushed green-gold in the throat) acting as mother to the smaller, ruffled, cream-coloured ‘Siloam Ury Winniford', with a dramatic maroon-purple throat.
To carry the cool palette through autumn, steely blue ‘Elijah Blue' fescue is a low-growing ornamental grass for filling gaps between plant clumps, and it's wise to include two Michaelmas daisies-‘Flora's Delight', with lilac-mauve, single flowers (each with a yellow eye), and ‘White Opal', a dwarf with frilly, yellow-eyed, double white blossoms. Finally, consider adding the frosty grey-green foliage of ‘Matrona' stonecrop (which sometimes has a hairline of pink showing along the edges of each leaf), with beet red stems carrying dusty pink flowers on which the season's monarch butterflies may want to rest.
In addition to herbaceous plants for the industrious gardener, it's also possible to add some low maintenance cool palette influences to the garden with small- to medium-sized trees and shrubs. ‘Iseli Foxtail' Colorado spruce has a tight pyramidal shape with striking light blue needles and can fill a corner as the one big tree in your garden, as can the ‘Vanderwolf's Pyramid' limber pine, with its stylized columnar form and long, vibrant blue-green clustered needles. The dwarf blue cypress ‘Boulevard' is silvery blue-green in summer and greyish blue in winter, and would easily fit into a shrub border, growing to two metres in height and spread, along with the bright blue ‘Blue Arrow' juniper, which is tightly pyramidal and grows to four metres tall but only 80 centimetres wide. ‘Blue Carpet' and ‘Blue Creeper' junipers have intense blue foliage and grow horizontally to form dense groundcover carpets. Or, for a softer, flowering groundcover that lasts from spring through autumn, Dalmatian bellflower offers violet-blue, bell-shaped blooms that almost hide its toothed, heart-shaped leaves. The plant spreads by underground roots to form a low, mounding mat.