Late-summer borders need some vibrant colours and lush foliage in the mix of planting to catch the glow of September sun. September is when many plants experience a final flourish before dying down for the rest of the season. Long-flowering, hard working plants are ideal so the colours last well into autumn. These are our top 10 recommended plants for border in September.
This graceful fuchsia will make a wonderful, lush shrub for the garden. It has relatively large, glossy green, willow-like leaves and bushy, copper stems. Its hummingbird-pollinated flowers are slimmer than those of F. magellanica, but otherwise look similar. The flowers are produced on the tips of the current season’s growth. Ideally, plant in a sheltered position and cut back hard in the spring to promote strong, arching shoots that will show off the flowers and foliage to their best. Feed periodically through the summer and treat for capsid bugs to ensure a good display. AGM*.
Height 2m. Origin Brazil. Conditions Good soil; sun or part shade. Hardiness RHS H2, USDA 8a-11. Season Summer to autumn.
Cleome Señorita Rosalita (= ‘Inncleosr’)
A fabulous, dense hybrid with typical spidery, rose-pink flowers and exotic-looking, dark-green, palmate leaves. Usefully, the flowers are sterile, so the energy that would have been spent on seed production goes into making a continuous string of flowers; this one is thornless too. Cleomes do best in a warm, sunny position. Incorporate humus on planting and feed through the growing season as they are hungry plants. It is a lovely alternative to the cosmos, salvias and dahlias normally seen in late-summer bedding.
Height 80cm. Origin Garden origin. Conditions Good moist soil; full sun. Hardiness RHS H1b, USDA 9a-10b. Season Summer to autumn.
I spotted this stunning species quite a few years ago in the garden at Pan Global Plants, but it took several years before I hunted down the seed to Ventnor Botanic Gardens on the Isle of Wight. The remarkable foliage is covered in a thick coating of golden felt, which makes the strongest impression on the margins of the new and slightly corrugated foliage. Growing this plant hard, in full sun on very free-draining soil will encourage the foliage to really colour up and will also keep the plant compact. The flowers are a forgettable brown yellow.
Height 1.2m. Origin Turkey. Conditions Best in poor, stony soil; full sun. Hardiness RHS H4, USDA 4a-10b. Season Year round.
From a huge nest of fresh-green leaves, strong flower spikes, are produced, each bearing a rather fat torch lily flower that is almost as wide as it is long. The flowers start orange-red and age to yellow and are produced well into October creating a magnificent floral full stop to summer. It was used very effectively at Great Dixter when combined with Cortaderia selloana ‘Pumila’, but would work well with grasses or larger, new-world salvias. Position carefully as plants reach nearly a metre wide and resent disturbance. Plant in good soil and tidy the old leaves in spring. AGM.
Height 2m. Origin South Africa. Conditions Good, rich soil; full sun. Hardiness RHS H5, USDA 7a-10b. Season Late summer to autumn.
Phlox paniculata ‘Herbstwalzer’
This useful, late-flowering form is at its best in September and it will sometimes continue to bloom into October. It produces large panicles of bold, pink flowers with a darker pink eye on strong stems, and is a useful antidote to the prevailing late-season yellows. Phlox thrive in well-nourished, acidic soil and resent periods of extended drought. In spring, feed the crowns with good compost and protect young shoots from forget-me-nots and the like, as this is the stage that they begrudge competition.
Height 1.2m. Origin Garden origin. Conditions A good garden soil and not chalk; full sun to part shade. Hardiness USDA 4a-8b. Season Summer to autumn.
Rudbeckia hirta ‘Cappuccino’
Rudbeckia hirta ‘Cappuccino’ is a fabulous selection that will make sturdy branching plants and will flower throughout the summer into autumn until colder days draw the show to a close. The huge daisy flowers are dark mahogany in the centre, bleeding to an amber yellow, and look absolutely divine in the soft autumnal sunshine, or cut for the house. Each flower will last for weeks and deadheading will help to keep the show clean and encourage more blooms. These are vigorous and greedy plants, it is important to feed the soil with good compost when planting and with fertiliser into autumn.
Height 1m. Origin Garden origin. Conditions Any rich soil that is not saturated; full sun. Hardiness RHS H3, USDA 3a-8b. Season Summer to autumn.
Hesperantha coccinea ‘Major’
Star-shaped, clear-red flowers are produced on gladiolus-like stems and held just above the thin, sword-shaped foliage. Crimson flag lilies hail from South Africa, so you might imagine they’re sun-loving, drought-tolerant geophytes. Sun-loving, yes, but they resolutely resent drought and will perform best in moist soils, and can even be used as marginal plants for ponds. They do especially well in Cornish gardens, and the west coast of Scotland. Plant in rich soil and split every couple of years to promote vigour and maintain flower production.
Height 50cm. Origin Garden origin. Conditions Good moist soil that doesn’t dry out for long periods; full sun. Hardiness RHS H4, USDA 7a-9b. Season Late summer to autumn.
Graham Stuart Thomas once commented that he could not write about sunflowers ‘with any enthusiasm’, and described their brilliant yellows, coarse leaves and need for staking with an air of disdain. He might have changed his mind had this perennial sunflower been around in his day. It’s quite different from the ubiquitous mustard yellow flowers of the late season border. The flowers are a lovely shade of soft primrose and are smaller and more numerous than other sunflowers. They are held on dark stems in loose clusters just above the foliage and will not run or require staking.
Height 1.4m. Origin Garden origin. Conditions Good rich soil; full sun. Hardiness RHS H6. Season Late summer to autumn.
Its large flower columns – composed of small, starry, mother-of-pearl green blooms that culminate in a top-knot of pineapple-like tufts of leaves – shoot up from the centre of large, basal rosettes of long, fleshy leaves. I saw it at Sissinghurst planted with Hylotelephium spectabile (then named Sedum spectabile) and Pennisetum alopecuroides, which was a superb and measured combination of colour, texture and form. The bulbs are massive and should be planted with the nose of the bulb just kissing the surface of improved soil that doesn’t sit too wet during colder months.
Height 1.2m. Origin South Africa. Conditions Rich, moist soil; full sun. Hardiness RHS H5, USDA 8a-10b. Season Summer to autumn.
Hylotelephium ‘Mr Goodbud’
I first saw ‘Mr Goodbud’ at an RHS Wisley sedum trial where it stood out from the crowd. It was compact and hadn’t fallen apart like the majority of the taller contenders, and the strong, pink flowers had presence. The flower heads are held in tight clusters, not dissimilar to broccoli, on thick stems above grey-green, succulent foliage. The blooms age to claret and will persist well into autumn. Plant in a sunny aspect in free-draining soil. Protect from slugs, but avoid using pellets – newts and frogs love to bed down among the cold, ice-plant foliage during summer.
Height 45cm. Origin Garden origin. Conditions Well-drained soil; full sun. Hardiness RHS H7, USDA 3a-9b. Season Summer to winter.
You can find more information on hardiness ratings here
Words Mat Reese
Photos Jason Ingram