Horticulture Magazine

25 Remarkable Long-Flowering Perennials

purple geraniums and bumblebee in an english summer garden

When the peak gardening season kicks in, you want your garden to be bursting with life and colour, and long flowering perennials are just the ticket.

Many perennials will offer second blooms to help prevent gaps in your garden, with little maintenance or additional planting required.

With some, you simply have to remove the flowers before they start seeding, and this will encourage another burst of flowers.

Maintain Plants For Longer Flowering

Other perennials just need to be cut back entirely after their first round of flowering, and should reflower again if fed and watered.

We also recommend deadheading to promote more prolonged flowering and help your garden to look its best for as long as possible.

hands deadheading echinacea flowers with secateurs

Deadheading prompts plants to direct their energy into new flowers rather than seed generation. [source]

To get the most out of your garden, we recommend planting in a mix of early, mid-year, and late bloomers.

This will keep things as colourful as possible, for as much of the year as possible.

There are lots of long-flowering perennials to choose from, all requiring different levels of care and maintenance – we’ve written this list to help you get started:

1) English Lavender

 bumblebees sat on lavender blooms
  • BOTANICAL NAME: Lavandula angustifolia
  • HARDINESS RATING: H5
  • POSITION: FULL SUN; PROTECTED
  • FLOWERING SEASON: SUMMER
  • POSSIBLE FLOWERING MONTHS: JUNE – JULY

With its fragrant leaves and long-blooming purple flowers, lavender has always been a firm favourite in English gardens.

Whether you have a country cottage garden or a more modern, contemporary design, lavender will always fit in and, as it can be grown in containers, it is perfect for even the most modest-sized spaces.

Lavender should be planted in spring from March to May in well-drained soil in a sunny, sheltered spot.

You’ll be rewarded with gorgeous flowers from late spring and all the way through summer.

They also attract bees and other important pollinators to your garden, so they really are a must-have. [source]

2) Catmint

a swallowtail butterfly sat on catmint blossoms
  • BOTANICAL NAME: Nepeta Cataria
  • HARDINESS RATING: H7
  • POSITION: Full Sun; Exposed or Protected
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: MAY – AUGUST

Nepeta, or catmint, is also well-loved by pollinators, and this aromatic beauty blooms from late spring to the middle of autumn, producing gorgeous clusters of lavender-blue flowers.

Catmint is easy to grow, and you should plant it out in spring.

For best results, plant it in sun or partial shade and in average to well-draining soil.

This plant is a great companion for vegetable patches thanks to its insect repellant properties, and also lends itself well to edging.

Take care to deadhead them to encourage further flowering.

3) Dahlias

orange dahlia flowers
  • HARDINESS RATING: H3
  • POSITION: FULL SUN; PROTECTED
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: JULY – OCTOBER

If well cared for and deadheaded when necessary, Dahlias can put on their show from midsummer all the way through until the arrival of frost.

With colours ranging from pretty pastels to boastful brights, Dahlias make a real statement in any garden.

These little showstoppers should be planted during late May to mid-June, depending on one when the frost has ended.

Dahlias prefer a sunny site in free-draining, lighter soil and you can boost your stocks by cutting and division, or by growing new plants from seed.

4) Yarrow

Achillea millefolium 'Lansdorferglut'
  • BOTANICAL NAME: ACHILLEA
  • HARDINESS RATING: H7
  • POSITION: FULL SUN; EXPOSED OR PROTECTED
  • FLOWERING SEASON: SUMMER
  • POSSIBLE FLOWERING MONTHS: JUNE – OCTOBER

One of the longest flowering perennials, yarrow is a bee and butterfly magnet.

It makes a lovely addition to herb gardens and flower beds.

Yarrow can be planted from October to March in full sun, and while it can thrive in almost any soil types, it much prefers well-drained soil.

This plant will produce adorable clusters of flowers in a vast range of colours, and by cutting it back thoroughly in late summer, you encourage fresh foliage and blooms.

5) Hardy Geraniums

violet hardy geranium flowers, with a bumblebee sat in one
  • HARDINESS RATING: H7
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: JUNE – OCTOBER

Reliable and long flowering, hardy geraniums can flower from April through till September in a variety of colours.

Tolerating both sun and shade they are best planted in well-drained soil and, if cut back after flowering, they will usually produce a second wave of blooms.

Hardy geraniums are also great self-seeders, and you will often find them flourishing in tiny cracks and spaces.

They are also well-loved by pollinators such as bees and hoverflies and provide a long season of nectar and pollen.

6) Spiderwort

blue Tradescantia blooming in the garden, green foliage in the background
  • BOTANICAL NAME: Tradescantia
  • HARDINESS RATING: H6
  • POSITION: PART SHADE; PROTECTED
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: JUNE – SEPTEMBER

Resilient and easy to grow, tradescantias are short-lived; however, they frequently flower and have superb grassy foliage.

Producing unusual, three petalled flowers and thriving in a range of soils, this perennial is perfect for hanging baskets as well as for ground colour and filling gaps in borders.

Flowering from late spring to late summer this cheerful and charming plant is a beautiful addition to any garden.

7) Daylily 

orange daylily flowers in bloom
  • BOTANICAL NAME: Hemerocallis
  • HARDINESS RATING: H6/7
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER
  • POSSIBLE FLOWERING MONTHS: JUNE – AUGUST

Also known as hemerocallis, this pretty little plant produces lily-like flowers that only last a day or two, but thankfully, in such an abundance that they span the period from Spring to late Summer.

With many colours to choose from, ranging from vibrant yellows and oranges to deep, burgundy-red, these plants bring a valuable flash of colour and life to your garden.

Plant hemerocallis in free-draining, fertile soil avoiding heavy shade as well as borders that are prone to drying out come summer.

8) Butterfly Bush

red admiral butterfly on buddleja davidii blooms
  • BOTANICAL NAME: BUDDLEJA
  • HARDINESS RATING: H6
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: JULY – OCTOBER

Also known as butterfly bushes, this deciduous perennial typically blooms from June through to September.

It can reach up to eight feet in height and sometimes more producing long pinnacles of blue and purple clusters of purple and blue flowers.

Buddlejas should be planted in full sun and well-drained soil and should be watered slowly and deeply during dry spells.

They are low maintenance and just require deadheading after flowering to prevent them from self-seeding.

As the name suggests, butterfly bushes are well-loved by butterflies as well as lots of other pollinators and beneficial insects.

9) Pincushions

violet flowers of Knautia arvensis
  • BOTANICAL NAME: SCABIOSA
  • HARDINESS RATING: H4
  • POSITION: Full Sun; Exposed or Protected
  • FLOWERING SEASON: SUMMER
  • POSSIBLE FLOWERING MONTHS: JULY – SEPTEMBER

Although a meadow-flower, scabious looks equally at home in a more formal, manicured garden and are also a wonderful gap-filler.

Flowering from June through to late August, this perennial comes in many colours, including white, blue and deep red.

Scabious prefer full sunlight but they will tolerate some shade and should be planted in moist, well-drained soil.

One single scabious can produce over two thousand seeds, which makes them a favourite amongst birds.

10) Black-Eyed Susan

field full of Rudbeckia fulgida var. sullivantii 'Goldstrum' flowers
  • BOTANICAL NAME: Rudbeckia
  • HARDINESS RATING: H6
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: JUNE – SEPTEMBER

With their daisy-like appearance that blooms for weeks, this prolific perennial will bring a nonstop cacophony of colour to your late-summer garden, typically flourishing from late June until the first frost.

Black-eyed Susan requires minimum effort and care and should be planted in full sun and well-drained soil.

Dead-heading will help prompt repeated flowering, and they are enthusiastic self-seeders.

You can also cut back this plant to encourage another burst of blooms in Autumn.

These care-free wildflowers are a great way to attract birds into your garden. 

11) Masterwort

summer flowering Astrantia major plants
  • BOTANICAL NAME: ASTRANTIA
  • HARDINESS RATING: H7
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER
  • POSSIBLE FLOWERING MONTHS: MAY – AUGUST

These sophisticated shade-lovers sport showy, star-like flowers in a range of different colours.

They also happen to be slug and snail-proof, making them an ideal asset for any border.

Astrantias should be planted in heavy, damp soil in full sun or dappled shade.

They will also benefit highly from home-made compost or leaf mulch.

Flowering from June to August, this plant provides a long season of colour and, by cutting the plant back after flowering, you can expect more foliage and more flowers.

12) Penstemons

pink and white penstemon trumpets
  • HARDINESS RATING: H4
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: JUNE – OCTOBER

Penstemons are excellent long-flowering perennials that are popular with bees.

If your border is lacking colour in late Summer, then this plant will make an immediate impact.

Grow penstemons is full sun to partial shade, in moist, well-drained soil.

This perennial can suffer in winter, so we recommend waiting to cut back until late Spring.

You can also take Summer cuttings to prevent later losses.

Plant penstemons in Spring, so they are well-established before the winter months.

Plant in groups of three or five and this plant will reward you with flowers right up to the first frost.

13) Peruvian Lily

peruvian lily flowers in orange
  • BOTANICAL NAME: Alstroemeria
  • HARDINESS RATING: H4
  • POSITION: PART SHADE; PROTECTED
  • FLOWERING SEASON: SPRING / SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: MAY – OCTOBER

Alstroemeria – or ‘Peruvian Lily’ – is a perennial flower native to South America.

It’s most likely to flower between the months of June and August, though you may see some varieties bloom earlier or later.

They will do best in a sheltered area that receives at least partial shade throughout the day.

There are many hybrids of this bushy plant and you can expect to grow many different colours and varieties – each with its own flowering period.

As it is only H4 hardy, you will need to offer some protection to the roots if you’d like the plant to return the following year.

Mulching well before cold weather and frosts set in is usually the best option.

14) Coneflower

bumblebee sat on Eastern Purple Coneflower
  • BOTANICAL NAME: Echinacea
  • HARDINESS RATING: H5
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: JULY – SEPTEMBER

The most popular variety of Echinacea, Echinacea purpurea (or ‘Purple Coneflower’) is a well-known favourite here in the UK, where it is H5 hardy.

You can expect its large, showy flowers to bloom in the summer months and attract a range of pollinators to your garden.

Those in full sun will generally flower better (and for longer), though they will still do well in part shade.

15) Geums

orange geums blooming in august
  • BOTANICAL NAME: AVENS
  • HARDINESS RATING: H7
  • POSITION: Full Sun; Exposed or Protected
  • FLOWERING SEASON: SPRING / SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: MAY – OCTOBER

Geums are hardy perennials that are commonly used as companion plants – especially in wildflower and cottage garden planting schemes.

They look great with campanula, hardy geraniums, hellebores and many other flowering perennial plants.

They have a very long flowering season and will usually appear in late-spring – sometimes lasting all the way until autumn.

Plant in full sun and divide every 3-4 years for the best results in your garden.

16) Stonecrop

stonecrop autumn joy variety
  • BOTANICAL NAME: SEDUM
  • HARDINESS RATING: H7
  • POSITION: FULL SUN; EXPOSED
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: AUGUST – OCTOBER

17) Clematis

Clematis Montana Pink Perfection flowers
  • HARDINESS RATING: VARIES
  • POSITION: VARIES
  • FLOWERING SEASON: ALL
  • POSSIBLE FLOWERING MONTHS: YEAR-ROUND

18) Phlox

summer flowers of Pink Phlox paniculata 'Eva Cullum'
  • HARDINESS RATING: H7
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: JULY – SEPTEMBER

19) Amsonia

blue flowering Amsonia tabernaemontana
  • HARDINESS RATING: H5
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SPRING / SUMMER
  • POSSIBLE FLOWERING MONTHS: MAY – JULY

20) Bellflower

two bellflowers with violet petals
  • BOTANICAL NAME: CAMPANULA
  • HARDINESS RATING: VARIES
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER
  • POSSIBLE FLOWERING MONTHS: JUNE – AUGUST

21) Valerian

red valerian blooms
  • BOTANICAL NAME: VALERIANA
  • HARDINESS RATING: H4
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER
  • POSSIBLE FLOWERING MONTHS: JULY – OCTOBER

22) Wallflower

yellow wallflowers blooms in spring
  • BOTANICAL NAME: ERYSIMUM
  • HARDINESS RATING: H5
  • POSITION: Full Sun; Exposed or Protected
  • FLOWERING SEASON: SPRING / SUMMER
  • POSSIBLE FLOWERING MONTHS: MARCH – AUGUST

23) Carnations

Canation 'Pink Kisses' flowering in summer
  • BOTANICAL NAME: DIANTHUS
  • HARDINESS RATING: H6/7
  • POSITION: Full Sun or Part Shade; Protected
  • FLOWERING SEASON: SPRING / SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: MAY – OCTOBER

24) Aster

Aster x frikartii 'Monch'
  • HARDINESS RATING: H6/7
  • POSITION: Full Sun; Exposed or Protected
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: AUGUST – OCTOBER

25) Hydrangea

pink hydrangea blooms
  • HARDINESS RATING: H5
  • POSITION: Full Sun or Part Shade; Exposed or Protected
  • FLOWERING SEASON: SUMMER / AUTUMN
  • POSSIBLE FLOWERING MONTHS: AUGUST – OCTOBER

Start planting those long-flowering perennials

Hopefully, by now, you are bursting with inspiration to help your garden boast colour for as much of the year as possible.

With so many long-flowering perennial plants to choose from, you will have no trouble getting the absolute most out of your garden whatever the style or size.

Make sure you do your research to ensure your plants flower for as long as possible, but with the right care, they will do the rest of the work for you.

So get planting, and reap the rewards of colour and happy pollinators that will truly make your garden a cut above the rest.

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