In the garden, summer can be a long season that starts in May and stretches right through to late September. This is a long time to maintain colour and interest. If your border has peaked in early summer don’t despair, it’s not too late to give your garden a boost by planting perennials that will flower through the second half of summer and into autumn. Here are my top plants for long-lasting summer colour.
With its tall, waving stems, topped by tight clusters of purple flowers that last all summer, it is no surprise that Verbena bonariensis has become a favourite border perennial. Despite its height, you can see through the slender stems so it can be planted towards the front of a border without obscuring plants behind.
The rich yellow flowers of this perennial rudbeckia start to appear from midsummer onwards but they keep going, lasting right through to autumn. Planted in a group, they bring a bright splash of colour to a sunny border and combine beautifully with other late bloomers like Helenium and Japanese anemones.
Better known as sedums, these robust, hardy succulents have fleshy leaves in shades of blue, green or purple that first appear in spring. Towards the end of summer they produce flat-topped heads of pink, white or purple flowers. The rigid stems last through autumn and into winter, making architectural forms in a border.
Hardy geraniums are among the most popular herbaceous perennials and Geranium ‘Rozanne’ must be the pick of the bunch. The scrambling stems cover the ground, displaying lavender blue flowers. It is a sterile hybrid so doesn’t produce seeds, which means the flowers just keep on coming all through the summer.
Salvia yangii (Perovskia)
Russian sage has stems of attractive, silver-grey foliage that grow from a woody base. It has tall spires of violet blue flowers in mid to late summer and after the flowers have faded, the silvery stems remain. This is a drought tolerant plant that does well in hot, sunny conditions.
Aster pyrenaeus ‘Lutetia’
Asters are a mainstay of the late summer garden and although Michaelmas daisies have now been moved to a different genus (Symphyotrichum), many beautiful plants remain in aster, including the lilac-blue Aster pyrenaeus ‘Lutetia’. Creating a loose mound, it produces its daisy blooms over several weeks in sun or part shade.
The wide, saucer-shaped flowers of Japanese anemones come in colours ranging from white and pale pink to magenta and purple. They can start to bloom in July but their main season is late summer into early autumn. They benefit from light shade as their leaves can scorch in hot, midday sun.
Astrantias flower from early to mid-summer but if conditions remain cool, they will keep going. If you cut them back after flowering, they often produce a second flush of blooms as temperatures begin to cool in late summer. The cupped-shaped bracts surround a cluster of tiny flowers, giving them the name Hattie’s pincushion.
Helenium ‘Sahin’s Early Flowerer’
Heleniums bring russet tones of deep rusty red, orange and yellow to a late summer border but as the name suggests, ‘Sahin’s Early Flowerer’ starts early, from midsummer onwards. It has a long flowering season producing its yellow flowers, streaked with orange and red, right through to September.
Nepeta racemosa ‘Walker’s Low’
Catmints have soft, grey-green leaves that form a bushy mound in a sunny position, at the edge of a border or spilling over a path. The violet blue flowers of Nepeta racemosa ‘Walker’s Low’ appear in spikes at the end of the stems from midsummer. Cut back faded flower stems to encourage more and keep the display going.