What to plant now for late-summer glory

It’s really important to keep your garden going for as long as possible, especially now that autumn tends to stretch into November due to our warming climate. There are plenty of plants capable of lifting your garden to new heights and, as the days begin to shorten, you’ll be rewarded with a jewel-box richness due to late-summer and autumn’s crystal-clear lightshow. 

Seek out substantial plants in the peak of perfection. Don’t be seduced by the ones in full flower, or the cheap shabby ones, however tempting they may be. Look for the promise of buds to come, or strong shoots, instead. Once home, give your treasures a long drink before you plant them. Buckets of water are very useful rehydrators. 

It’s definitely daisy time

We’re approaching daisy season, and the central hub in the middle, consisting of hundreds of tiny flowers, is a pollinator buffet that lasts for many weeks. The best perennial late-summer yellow daisy of all is Deam’s sunflower, Rudbeckia fulgida var. deamii. From a distance, this looks like a series of spinning plates, because the modestly sized flowers are held horizontally, not vertically. The warm yellow ray petals surround crisp brown middles and the handsome foliage persists until autumn, without showing any sign of frazzle. Think of a debonaire Fred Astaire with patent pumps and spats.

This yellow daisy is perfect for the front of a border, placed against the slightly shorter violet long-lashed flowers (should I mention Elizabeth Taylor here) of an Italian aster – Aster amellus. There are two of note, ‘Veilchenkönigin’ (sometimes sold as ‘Violet Queen’) and the slightly paler ‘King George’. European asters, which are still called asters following a vast botanical reshuffle, are all drought-tolerant once established. If these two prove elusive, opt for the long-flowering Aster x frikartii ‘Mönch’, the longest flowering lavender aster of all. It performs from July until September and I couldn’t do without its cloud of soft lilac daisies. It generally reaches three feet in height (90cm), perhaps more, and it softens border edges like late-summer clouds. 

September-flowering asters tend to be taller, up to four feet (120cm), so they are more middle-of-border than edge. The shiny black stems and foliage of Symphyotrichum laeve ‘Calliope’ flatter the soft blue-lilac flowers and this dramatic aster has rigid straight stems that rise up every now and again, so it looks great long before it flowers. I’d also seek out Symphyotrichum ‘Little Carlow’ too, for its multitude of tiny cornflower-blue flowers held in buds criss-crossed in red diamonds. If you want to light up late-autumn, Symphyotrichum oblongifolium ‘October Skies’ is perfect for a sunny edge because it’s only 18 inches high.

A well-placed container to distract the eye

You’ll definitely find echinaceas at this time of year too; many of the showier ones, with names in single italics, are America-bred and don’t always manage to come through wet, warm British winters. This is especially true of the oranges and reds. As a result, they are best off being planted in containers and treated like an agapanthus, taken under cover in October. Echinacea purpurea is seed-raised, so there’s less of a problem, and these can be slotted into a border. Try ‘Magnus’ and ‘White Swan’.

Cream, lime-green and white hydrangeas are having a renaissance, and they make great container plants in slightly shady positions. Avoid the demanding ‘macrophyllas’ and go for something more weather tolerant with medium-sized flowers. H. paniculata ‘Limelight’ will need a sizeable container, as will the red-stemmed ‘Wim’s Red’. ‘Kyushi is a delicate, lacy white and there’s also ‘Little Lime’. The latter two can be accommodated in medium-sized planters. H. arborescens ‘Lime Rickey’ and ‘Annabelle’ have domed flowers that look good in a border or large container. Hydrangeas offer much to the gardener and flower arranger alike, for their flowers fade beautifully to shades of parchment and pink. They’re equally good in the ground.

Dark highlights add drama

Foliage is just as important as flowers, and dark foliage makes a real impact on the eye. Border sedums, now called Hylotelephium, don’t flag in August due to their plump, water-filled foliage. Look out for the following: the almost black ‘Jose Aubergine’, the dusky-leaved ‘Xenox’, the chocolate-leaved ‘Purple Emperor’, the pigeon-breast-grey ‘Matrona’ and the purple-tinted ‘Dark Magic’. Their domes of starry red or pink flowers fade to chocolate-brown as temperatures drop.

Sultry-coloured penstemons please the eye and the bees and they also add all-important vertical accents. Dead-headed, they will flower until late. ‘Andenken an Friedrich Hahn’, sometimes sold under the old name of ‘Garnet’, is a floriferous ruby-red centurion, having been named in 1913. It’s also hardier than many others. ‘Pensham Plum Jerkin’ has damson-black flowers and ‘Raven’ is rich blue-purple flowers. You will also find Verbena ‘Bampton’, a long-flowering short verbena with dark crinkly foliage flecked with small lilac flowers. It will self-seed pleasingly in the future. There will be dark, fluffy pennisetums on offer too, with bottle-brush flowers that cling on like large hairy bear caterpillars. ‘Black Beauty’ is the darkest of all and this will overwinter under cover. Later autumn performers, with sultry foliage, include the cimicifugeae, now called Actaea. ‘Chocolate’ and ‘Brunette’, both grown for their lacy dark foliage and pale-pink fragrant spires, will need rich, most soil and dappled shade however.

Some Southern Hemisphere razzle dazzle

Plants found close to the equator, or from the Southern Hemisphere, have a different time clock. They are prompted into flower as the days shorten and cool, so they peak in late-summer and autumn here and go on until frost cuts them back. Their brightly coloured pigment-packed flowers come in vibrant colours, including clear red and royal blue.

Dahlias are among the best and it’s the double-flowered ones that make more impact. The singles please the bees more, admittedly, but they need regular deadheading, so it’s swings and roundabouts. They all cut well though and the tubers can be stored over winter. ‘Soulman’ is tall and upright, with long stems topped with flowers containing a dark-red fluffy middle, a rakish ruff of swept-back outer petals and handsome foliage. Other sultry ones include ‘Sam Hopkins’ and ‘Karma Choc’. ‘Mystic Yellow’, once known as ’Knockout’, has yellow single flowers and chocolate foliage. ‘David Howard’, a butterscotch with khaki foliage, slots into the autumn colour palette really well.

Tender salvias are everywhere now and very suited to being grown in pots. The tall dark-blue ‘Amistad’, along with a crimson-pink named ‘Amante’ and a purple named ‘Amigo’, have slender flowers held in darker calices or bud cases. These showy salvias aren’t hardy for most of us, but they can be raised from cuttings. The woody and hardier Lips Series features ‘Hot Lips’, a red and white, and ‘Amethyst Lips’, a purple and white. Salvia ‘Love and Wishes’, the best of the Wishes Series, has vibrant-pink hummingbird pollinated flowers held in dark papery cups. They all enjoy being watered. 

Chocolate cosmos, grown for its dark-chocolate scented flowers on long, wiry stems, has a new friend named ‘Cherry Chocolate’. It was the runner up in the RHS Chelsea Flower Show Plant of the Year 2024. The foliage is more than black, but the cherry-pink flowers seem to be more abundant. I’d containerise this one.

The really late show

Look out for Rudbeckia triloba, a short-lived perennial with small yellow daisies buttoned in brown. The orange flowers of Kniphofia ‘Happy Halloween’ make October special and there are later flowering barley-sugar flowered crocosmias to hunt down. They include ‘Star of the East’ and ‘Golden Ballerina’. Gaura has had a rebrand – it’s Oenothera now, but it carries on producing small butterfly-shaped flowers until November, always with a soft hint of pink. It would pick up the madder-pink mallow-like flowers of a sub-shrub named Anisodontea ‘El Rayo’, a plant that flowers for 10 months of the year – and it came through last year’s wet winter for me.