Rudbeckia hirta 'Cappuccino'. Photo by Jason Ingram

September plants for a late-summer glow

Our pick of ten plants which are at their best in September to create borders that will give your garden a late-summer glow. Photos by Jason Ingram.

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 recommended plants for border in September.
1

Fuchsia hatschbachii

Fuchsia hatschbachii. Photo by Jason Ingram

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.

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Height 2m. Origin Brazil. Conditions Good soil; sun or part shade. Hardiness RHS H2, USDA 8a-11. Season Summer to autumn.

2

Cleome Señorita Rosalita (= ‘Inncleosr’)

Cleome. Photo by Jason Ingram

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.

3

Phlomis leucophracta

Phlomis leucophracta. Photo by Jason Ingram

The remarkable foliage of this stunning species 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.

4

Kniphofia rooperi

Matthew Reese/Nurseryman's Choice - September (13th September 2016)

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.

Height 2m. Origin South Africa. Conditions Good, rich soil; full sun. Hardiness RHS H5, USDA 7a-10b. Season Late summer to autumn.

5

Phlox paniculata ‘Herbstwalzer’

Matthew Reese/Nurseryman's Choice - September (13th September 2016)

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.

6

Rudbeckia hirta ‘Cappuccino’

Matthew Reese/Nurseryman's Choice - September (13th September 2016)

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.

7

Hesperantha coccinea ‘Major’

Matthew Reese/Nurseryman's Choice - September (13th September 2016)

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.

8

Helianthus ‘Carine’

Matthew Reese/Nurseryman's Choice - September (13th September 2016)

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.

9

Eucomis pallidiflora

Matthew Reese/Nurseryman's Choice - September (13th September 2016)

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. At Sissinghurst Castle in Kent it was 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.

10

Hylotelephium ‘Mr Goodbud’

Hylotelephium 'Mr Goodbud'. Photo by Jason Ingram.

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.

11

Persicaria amplexicaulis Taurus (=’Blotau’)

Persicaria 'Taurus'. Photo: Jason Ingram

The range of Persicaria amplexicaulis now available to plant lover’s is potentially bewildering. But it you choose to measure performance against reliability, flower colour and longevity this one comes pretty near the top in the rankings. It was a chance seedling, identified by Alan Bloom at Bressingham in Norfolk. Vibrant rose-madder flowers are marginally shorter than the species, and swollen in girth to impressive effect. Individual flowers sport a tuft of electric blue stamens. Extended flowering period is a bonus.

Height/spread 100cm x 70cm. Origin Persicarius originate in Northern temperate regions. Soil Prefers a humus-rich, moisture-retentive soil, but copes with less. Season July to October.

12

Veronia arkansana ‘Mammuth’

Vernonia Crinita. Photo: Jason Ingram

Ephemeral detail can ebb and flow but behind every successful border stands a framework of reliable structure plants that endure. Here, stems the thickness of a man’s finger reach up nearly two metres without need for support. When September brings golden daisies and wheaten grasses, the flattened heads of Vernonia, each having myriad small composite flowers, stand out in purple splendour. It serves well as fine marker points in formal planting and is equally successful mixed with a range of meadow grasses in wilder spaces.

Height/spread 175cm x 80cm. Origin Native to eastern North America. Soil Most well-drained loams in full sun. Season August to October with good structure beyond.

13

Miscanthus sinensis ‘Emmanuel Lepage’

Miscanthus Emmanuel Lepage. Photo: Jason Ingram

Originally a gift from French nurserymen Monsieur Lepage, this was a chance seedling in his stock beds in the Loire. He selected it for good form and colour and named it after his father. Miscanthus sinensis cultivars contribute reliable height, colour and movement from August to February. This one is particularly valuable retaining fresh green foliage pretty much until Christmas. Prolific flowering stems unfurl to display gently arching plumes with a silken sheen the colour of café au lait. It is a fine partner to Eupatorium cultivars.

Height/spread 200cm x 100xm. Origin Miscanthus sinensis species originate in Southeast Asia. Soil Most Moisture-retentive garden loams. Season August to November.

14

Aster sedifolius ‘Nanus’

Aster Sedifolius Nana. Photo: Jason Ingram

Front edges of borders, like a pretty smile, get noticed, and unsightly dark spaces in either can be alarming. This slender upright aster is eminently suitable for a front row position, ensuring colour into autumn. Reliable and mildew resistant, it requires little attention. Branched stems support plentiful composite flowers, opening to lavender blue in August. A bonus is the attractive wheaten structure which remains well after flowers fade. ‘Nanus’ was first seen on the stony banks of Lake Baikal in Siberia, where it withstands prolonged harsh winter temperatures.

Height/Spread 40cm x 30cm. Origin South and east central Europe to northern Asia. Soil Well-drained loam in an open aspect. Season August to September.

15

Sedum telephium subsp. ruprechtii

Sedum Ruprechtii. Photo: Jason Ingram

Not every sedum is pink; I like the mellow buff tones of these flowers as a complement to the dark purples and blues of late summer. Newly opened blooms on this more sprawling plant are a creamy yellow, against a glaucous foliage. Long summer days bring on a darkening of flower tone. By the first frosts, flowers have acquired a light biscuit bronze, and foliage is marked with attractive pink flushes. Mixed with Euphorbia polychroma and Stipa calamagrostis in a gravel scree, the cameo endures from May to October.

Height/Spread 40cm x 40cm. Origin Widely distributed throughout northern temperate regions. Soil Free-draining garden loam, tolerant of lean nutrient conditions. Season July to September.

16

Eryngium ebracteatum

Eryngium Ebracteatum. Photo: Jason Ingram

At first glance you might easily mistake this plant for a Sanguisorba. Wiry stems bear multiple flowers in warm claret tones, so redolent of the Sanguisorba family. But the fine upright habit and slender saw-edged leaves confirm a tolerance of more arid conditions. Both plants contribute a strong architectural statement in scree or gravel planting. Position where the flower heads can be silhouetted against a late summer sky, and protect from winter wet to preserve the plant for future years. Collect some seed anyway, for added insurance against unpredictable British winters.

Height/Spread 100cm x 45cm. Origin South America. Soil Free-draining alkaline to neutral soils. Season July to September.

17

Persicaria virginiana var. filiformis

Persicaria Filiforme. Photo: Jason Ingram

As other plants begin to wane, this Persicaria justifies its place in the garden. Principally grown for the velvet textured foliage, its emerald leaves are symetrically marked with an attractive chocolate brown blotch. Wine-red stems repeatedly branch into an airy structure, the terminal wisp of stem so slender it is scarcely visible. Until, that is, tiny flower buds open to reveal a perfect pinpoint of vivid scarlet.

Height/Spread 65-80cm x 50cm. Origin Species introduced from America by John Tradescant the younger. Soil Prefers a moisture-retentive soil in light shade, protected from harsh winds. Season Foliage from June, flowers from September.

18

Crocosmia x crocosmiiflora ‘Star of the East’

Crocosmia 'Star of the East'. Photo: Jason Ingram

This plant presents the perfect example of how a glorious orange flower lift the spirits and brightens a fading border. Coral buds open to star-shaped blooms up to 10cm across, with masses of sword-like green foliage. A triumphant marriage of beauty and resilience and awarded an RHS Award of Garden Merit. ‘Star of the East’ is an Earlham hybrid raised by George Davison who thereafter turned to apple breeding, believing the form could never be surpassed. A confident commendation!

Height/Spread 70cm x 35cm. Origin Crocosmia species originated in South Africa. Soil Moisture-retentive loam, preferably not drying excessively in summer months. Season Late August to end September.

19

Verbena bonariensis ‘Lollipop’

Verbena Bon 'Lollipop'. Photo: Jason Ingram

We still sell more Verbena bonariensis than any other plant, but you may not have sampled this diminuitive version and I urge you to investigate. Flattened congested clusters of vibrant purple flowers are held aloft on rigid stems. Longevity of flowering display contributes greatly to its value in feature planters and high profile beds. Used with Erigeron karvinskianus and Molinia caerulea subsp. caerulea ‘Moorhexe’, a large planting trough provided a billowing show of colour and texture from June to November, with almost no watering required.

Height/Spread 60cm x 30cm. Origins Species originates from Buenos Aires, after which it is named. Soil Tolerates well-drained thin and lean soils in sunny aspect. Season June until first frosts.

You can find more information on hardiness ratings here

Words Mat Reese

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Photos Jason Ingram