With each day already a fraction shorter, the end-of-summer garden has been nurturing large-scale plants that are finally in bloom. ‘Gateway' Joe Pye weed, which is more compact than its cousins but still reaches 1.5 metres tall, requires consistently moist soil. Another water-loving companion of suitable size and distinction is ornamental Chinese rhubarb. With them is Russian sage, a bushy, upright grower with fine-textured grey-green foliage, and many flower stalks extending cool-blue florets for several weeks at summer's end. Russian sage likes slightly drier soil, and amending the planting hole with sand and fine gravel will give this plant the quick drainage it prefers.
The aster season is soon upon us with hundreds of species and cultivars to choose from. A few precocious new varieties pop open their flowers in August, such as Violet Queen Italian aster, with yellow-eyed sprays of violet-purple daisies, and ‘Bluebird' smooth aster, with red stems carrying single, violet-blue flowers (a tall plant, but it won't require staking if grown in full sun). Among the pink hues are mid-size pastel ‘Pink Cloud' heath aster and compact, lilac-mauve ‘Flora's Delight'. But to preserve myself from plant snobbery, I search roadsides and forgotten patches for tiny species asters, blooming as they have for hundreds of years since arriving as seeds in the pockets of colonists. There's room for all kinds in my garden.
Opposites and similarities
Combining plants with complementary features adds style to a grouping. The likeness might be in varying shades of a common colour, such as deep pink phlox, purple coneflower (Echinacea spp.) and pale pink daylilies (Hemerocallis spp.). Or the similarity could work as well with form, combining tall and wiry flower stalks of beard-tongue (Penstemon spp.), false or prairie mallow (Sidalcea spp.) and perennial sage (Salvia).
Pairing plants with opposite characteristics also creates interest, as with the low, spreading form of stonecrop (Sedum) surrounding tall mulleins (Verbascum).
Colour contrasts also make for stylish combinations; for example, matching black mondo grass (Ophiopogon planiscapus ‘Nigrescens') with silver lambs' ears (Stachys byzantina).
Seasonal partners (early summer)
Lady's mantle (Alchemilla mollis), 45 x 45 cm, light shade to full sun, Zone 3
Clematis x durandii, 1.5 m, full sun, Zone 5
‘Moonbeam' threadleaf tickseed (Coreopsis verti-cillata ‘Moonbeam'), 45 x 60 cm, full sun, Zone 3
‘Alba' purple foxglove (Digitalis purpurea forma albiflora), 120 x 30 cm, full sun to part shade, Zone 5
‘Ann Folkard' geranium (Geranium ‘Ann Folkard'), 45 x 90 cm, full sun to part shade, Zone 5
Midnight Reiter cranesbill geranium (G. pratense Midnight Reiter strain), 23 x 30 cm, full sun to part shade, Zone 4
Rozanne geranium (Geranium ‘Gerwat' Rozanne), 45 x 90 cm, full sun to part shade, Zone 5
‘Kobold' blazing star (Liatris spicata ‘Kobold'), 50 x 20 cm, full sun, Zone 2
‘Connecticut King' Asiatic lily (Lilium ‘Connecticut King'), 75 cm, full sun, Zone 4
‘Canon J. Went' purple toadflax (Linaria purpurea ‘Canon J. Went'), 75 x 25 cm, full sun, Zone 4
‘Snow and Sapphires' Jacob's ladder (Polemonium caeruleum ‘Snow and Sapphires'), 60 x 45 cm, full sun to part shade, Zone 4
‘Hewitt's Double' Yunnan meadow rue (Thalictrum delavayi ‘Hewitt's Double'), 120 x 45 cm, part shade to full sun, Zone 4