8 Autumn-Flowering Perennials For Late Interest Recommended By Garden Designers
Ed is a horticultural therapist, professional gardener and writer. Ed has a BSc in Occupational Therapy from Coventry University and a Diploma in Social and Therapeutic Horticulture (DipSTH) via Thive, the RHS and Pershore College. Ed runs a community kitchen garden in West Sussex, where he leads horticultural therapy sessions.
Reviewed By COLIN SKELLY
Colin is a Horticulturist and Horticultural Consultant with experience in a range of practical and managerial roles across heritage, commercial and public horticulture. He holds the Royal Horticultural Society’s Master of Horticulture award and has a particular interest in horticultural ecology and naturalistic planting for habitat and climate resilience.
Contributions From PAUL HERVEY-BROOKES
Paul Harvey-Brookes is a Garden Designer and recently won a People’s Choice Award and Gold Medal at RHS Hampton Court in 2023. He has a degree in Landscape Architecture from the University of Gloucestershire and a Diploma in Plantsmanship from Royal Botanic Garden Edinburgh. Paul has been a Gardens Judge & Assessor for the RHS since 2015, judging entries at RHS Flower Shows across the UK.
Lachlan Rae is a Horticultural Consultant and Garden Designer who runs his own Garden Management company. He has appeared as a judge on the TV show Garden of the Year on More4 and was awarded The Young Horticulturist of the Year award in 2017 by the Chartered Institute of Horticulture. Lachlan trained in Botanical Horticulture at the Royal Botanic Garden in Edinburgh.
Autumn can sometimes be thought of as the end of the summer colour in the garden and the arrival of autumnal foliage.
But it needn’t be, as there are some wonderful perennial plants that continue blooming or begin to burst into flower at the end of the summer, providing some stunning late-season interest.
“Autumn is my favourite time of year to be in the garden, because it is beautiful and also never too hot or wet,” shares Paul Hervey-Brookes, an award-winning Garden Designer.
What’s more, being perennial and presuming the winter is not too harsh, these plants will keep coming back year on year, providing great value for money.
Perennials are also relatively maintenance-free, often requiring only deadheading and cutting back at the end of the year.
1) Japanese Anemone
- HARDINESS RATING: H7
- TYPICAL FLOWERING MONTHS: AUGUST – OCTOBER
- RECOMMENDED VARIETY: Anemone x hybrida ‘Honorine Jobert’
From the Ranunculaceae family, these flowers are herbaceous perennials, most originating, not from Japan, but from China.
Japanese anemones really come into their own in autumn. They begin to flower in late August and will continue until October or the arrival of the first frosts.
They are happiest in either full sun or part shade and prefer a moist, well-drained soil. They are hardy, but may however struggle in wet winters.
Flowering in either pinks or whites on tall stems rising above the foliage, they are great for the back of the border.
After flowering, cut back the stems and remove any dead foliage in early spring.
Beware though, Japanese anemones don’t like being moved once established and have a tendency to spread, almost to the point of being invasive.
If there is space for only one, Anemone × hybrida ‘Honorine Jobert’ is a stunning plant.
Growing to H1.5m x W1m, in almost any soil, it produces pure white single flowers for months on end.
2) Aster
- HARDINESS RATING: H7
- TYPICAL FLOWERING MONTHS: JULY – OCTOBER
- RECOMMENDED VARIETY: Aster × frikartii ‘Mönch’
Better known as the Michaelmas daisy, although recently classed botanically as Symphyotrichum, perennial asters are often described as a stalwart of late summer and early autumn colour.
Available in blue, purple, pink and white, there is one for every garden.
A favourite of pollinators, they will attract wildlife into the garden and flower for months on end from July until the first frosts.
Ideal for a cottage garden scheme, asters grow well in any well-drained soil apart from clay.
Preferring full sun, they can cope with a sheltered or exposed site.
They can be cut back after flowering or the seed heads left on for winter interest and the birds to forage amongst during the colder months.
For stunning purple-blue flowers with a yellow centre, blooming from July until October, try Aster × frikartii ‘Mönch’.
With good resistance to mildew and growing to 1m in height and 0.5m wide, it is perfect for a mixed border or a container but may need staking earlier on in the year.
3) Sedum
- HARDINESS RATING: H7
- TYPICAL FLOWERING MONTHS: AUGUST – OCTOBER
- RECOMMENDED VARIETY: Sedum ‘Autumn Joy’
Sedum, or as they are now known as ‘Hylotelephium’, are a group of hardy and sun-loving perennials.
With star-shaped flowers set in clusters, they flower from summer into autumn.
A drought-tolerant plant, they prefer full sun and grow best in a south-facing spot and well-drained soil.
As a valuable source of nectar later in the year, they are loved by pollinators and require little maintenance, as their faded stems can be left for winter interest and cut back in early spring.
Hylotelephium ‘Herbstfreude’ or as it was better known – Sedum ‘Autumn Joy’ – is a great variety producing vibrant pink flower heads which darken to red over time and brown over winter.
With an eventual size of 0.6m tall and 0.4m wide, it looks great planted alongside ornamental grasses.
4) Salvia
- HARDINESS RATING: H3
- TYPICAL FLOWERING MONTHS: MAY – SEPTEMBER
- RECOMMENDED VARIETY: Salvia ‘Amistad’
Salvias, or ‘sages’, are a wide group of plants including microphylla, nemrosa and sylvestris cultivars.
“I think the best thing you could possibly do is to take a loam-based compost, add it to your container and place a Salvia microphylla into the pot,” shares Garden Designer Lachlan Rae.
“Having said that, there are so many varieties to use that are all relatively hardy.”
Whether as annual bedding or perennial plants, they are a must-have for any border or container.
With so many to choose from, the perennial Salvia ‘Amistad’ has to be a firm favourite though.
Producing the most stunning deep purple flowers and black calyces, it really stands out.
Growing in an upright habit to H1.2m x W0.5m, it is well suited to the back of the borders and will flower, if deadheaded regularly, from May through to the end of September.
A drought-tolerant plant, it requires a sunny and sheltered spot – a south-facing border is ideal.
Even though hardy it may not survive the worst winters, but thankfully it takes easily from cuttings to provide backups.
5) Nerine
- HARDINESS RATING: H5
- TYPICAL FLOWERING MONTHS: AUGUST – OCTOBER
- RECOMMENDED VARIETY: Nerine bowdenii ‘Isabel’
Nerine bowdenii, or the ‘Bowden lily’ is a hardy, bulbous perennial and part of the Amaryllidaceae family.
Originating from South Africa it is no surprise that it favours a well-drained soil and south-facing aspect. So much so that it will not flower if planted in shade.
The flowers protrude above its bright green foliage and will brighten up the autumn months from September until November.
Growing to around H.5m they are well placed for the front of the border or a container.
Nerine bowdenii thrive in poor soil – if the soil is too rich it will encourage more foliage rather than blooms.
They hate to be moved so only do so if necessary and don’t despair if they don’t flower afterwards, as they will more than likely bloom the following year.
For a spectacular pink flower 8cm across, Nerine bowdenii ‘Isabel’ is worth considering.
Growing to 0.5m tall and 0.1m wide, it will benefit from a mulch after flowering to help protect over winter.
Over time the bulbs will make offsets and form a clump, even becoming crowded, but don’t worry as they will often flower better when allowed to bulk up.
If blooms decrease and the clump gets really large, then they can be divided up and replanted in spring.
6) Echinacea
- HARDINESS RATING: H5
- TYPICAL FLOWERING MONTHS: JULY – SEPTEMBER
- RECOMMENDED VARIETY: Echinacea purpurea
Echinacea or ‘coneflowers’ as they are commonly known, originate from North America and must be one of the best plants for late summer and autumn colour.
Being a rhizomatous perennial, they die back over winter and new growth appears in spring.
Preferring full sun, they will tolerate some shade and are most at home in a south-facing spot.
Displaying daisy-like flowers in a range of colours including, orange, red, pink and white, they are certain to add an injection of colour later in the year.
Now very popular due to prairie style planting, they look equally good in a cottage garden and are loved by pollinators.
“To provide a long season of nectar for pollinators, using late summer or early autumn flowering perennials is a must,” explains Master Horticulturist Colin Skelly.
“There aren’t many native UK later flowering plants, so using plants like Echinacea and the others in this list, can really help to give a boost to the resources available to pollinators in the UK.”
Echinacea purpurea or the purple coneflower is a striking example, producing huge 12cm diameter purple flowers in summer until right into the autumn.
Reaching H1.5m x W0.5m they look great at the back of the border and do best in well-drained soil.
7) Rudbeckia
- HARDINESS RATING: H6
- TYPICAL FLOWERING MONTHS: AUGUST – OCTOBER
- RECOMMENDED VARIETY: Rudbeckia fulgida var. sullivantii ‘Goldsturm’
For a dazzling yellow late summer display of colour, Rudbeckia or black-eyed Susan as they are also known, can’t be beaten.
From July, Rudbeckia produces bright yellow flowers with a brown central disk.
A stunning plant, it is perfect for planting in drifts amongst other perennials or ornamental grasses.
Originally from North America, they can be annual, biannual or perennial and are particularly easy to grow.
Preferring a moist and fertile well-drained soil, they will thrive in a south-facing spot and are lovely as a cut flower due to their long stems and vase life.
Most varieties here in the UK are perennials, apart from Rudbeckia hirta, which is not reliably hardy here in the UK and tends to be grown as an annual.
Out of the herbaceous perennial varieties, Rudbeckia fulgida var. sullivantii ‘Goldsturm’ is one of the best known and for good reason.
It produces an abundance of large flowers on tall stems until the first frosts and is reliably hardy.
Listed by the RHS as a plant for pollinators, it will bring bees and other pollinators into your garden when in flower.
8) Agastache
- HARDINESS RATING: H6
- TYPICAL FLOWERING MONTHS: JULY – SEPTEMBER
- RECOMMENDED VARIETY: Agastache ‘Blue Fortune’
Agastache or giant hyssop is a perennial plant that blooms on spires from July until October.
Usually with purple or mauve flowers, other colours now include orange and pink.
A tough plant, it is drought tolerant and can put up with poor soil.
It requires full sun, ideally in a south or west-facing situation.
It can add great height and structure to the garden, but is a short-lived plant and may need replacing every few years.
Agastache ‘Blue Fortune’ is a wonderful plant sending up spikes of violet-blue flowers for months on end.
Growing to H1m x W0.5m it looks equally good in a border or container.
The flowers are a favourite of bees and can be left once faded to add some interest over the winter months.
Autumn doesn’t have to mean the demise of colour in the garden, so why not try some of these late-flowering perennials to extend the flowering season.
