Top 10 Flowers that Bloom all Season UK

Updated/Fact-Chacked on April 14, 2023 by John

I want a plant to give me flowers for months, unlike fly-by-night tulips, where lifespan in bloom can be as little as two weeks. I want value for money with low maintenance.

I’ve spent hours researching plants and flowering times to build a list of the best options for a long, colourful season. I’ve chosen to include plants that flower in all seasons so you can achieve maximum colour all year round. I have also been testing each flower to see what results I get in my garden. I will continue testing different varieties and keep this post updated.

My list of the longest flowering plants below is related to the UK climate, but many of these plants will have long flowering months worldwide.

To get the most out of your long flowering plants, you need to keep on top of your deadheading and ensure they have optimal nutrients to thrive.

Longest Flowering Plants According to My Tests 

Begonias

Flowering time: June -October

I fell in love with Begonias this summer. After buying my friend a cheap £1.99 begonia plant from Tesco, I couldn’t believe the amount of flowers it produced this summer – and it’s still going at the time of writing (end of September). The plant has amazing rose-like flowers and received very little maintenance over the summer months; currently questioning why I keep maintaining my roses (but that’s another post).

According to Gardeners World, begonias do best out of direct sunlight; my friend’s begonia has been in direct sun all summer and is thriving. Plant begonias in well-drained soil at the front of any border and be amazed by its bountiful flowers. Begonia tubers can be purchased in March or you can buy a plant from your local supplier. Note the ‘foliage begonias’ are generally grown as house plants.

Begonia varieties include: Begonia ‘Senator IQ White’, Begonia ‘Apricot Shades’, Begonia ‘Big’, Begonia ‘Million Kisses Elegance’, Begonia ‘Glowing Embers’, Begonia ‘Illumination’, Begonia ‘Waterfall’, Begonia ‘Majestic Sunburst’. Begonia ‘Beauvilia’, Begonia ‘Super Cascade’, Begonia ‘Madame Richard Galle’, Begonia luxurians, Begonia ‘rex’, Begonia ‘Non Stop White’

Brookside nursery has some fantastic, unusual varieties of begonia well worth checking out.

Viola

Flowering time: May-January

I’ve spent hours researching plant flowering times in the UK, and nearly forgot the one plant staring back at me from my patio as I write this article. The Viola! When all your autumn flowering plants start fading, the fabulous viola just keeps rocking through the winter months.

Violas come is so many varieties, you could spend hours matching your plants or just buy a mix. Violas are great for making up autumn/winter pots to add colour to areas of the garden that look drab; here’s my most recent pot creation sitting on my outdoor table.

Some violas will flower in early summer; to get the most out of a container, mix summer/autumn/winter flowering viola for continual colour. Violas combine well with small grasses for structure and other colourful flowers with larger heads, like chrysanthemums and Marigolds.

Viola varieties include: Bowles Black, Odorata, Tricolor, Heartsease, Red wing, Ruby and Gold, White jump up, Vibrante white blotch.

>> Best tall flowering plants for the back of border

Dahlias

Flowering time: July-October

Dahlias give you a long bloom into late October but tend to start late around July. There are so many different colours of dahlias that it’s impossible to find a variety that wouldn’t fit in a border; they also come in unlimited shapes and sizes, and you wouldn’t know some were actually dahlias.

Dahlias also make great cutting flowers to bring indoors for vases; cutting the flowers only makes the plant produce more.

Dahlias can be bought as plants or grown from tubers, cuttings and seeds.

Dahlia varieties include: Dahlia Anemone, Dahlia Cactus, Dahlia Ambition, Dahlia Apache,Dahlia Apricot Desire, Dahlia Arabian Night, Dahlia Art Deco, Dahlia Babylon Paars, Dahlia Bishop of Canterbury

Pelargoniums

Flowering time: April- September, May-October

We are talking here about pelargoniums, commonly called ‘geraniums’, not hardy geraniums – knowing the difference is essential gardening knowledge! Pelargoniums are a great versatile plant for adding colour to borders and containers. They do best in full sun with well-drained soil, but are not fussy about soil PH. Pelargoniums don’t do well in harsh winters and are best brought indoors; often used as annuals and composted at the end of their flowering season.

Pelargoniums respond well to being cut back to reinvigorate the plant, but don’t like any form of fungus which can appear if dropped petals are not collected.

Pelargoniums are fantastic in container designs as they can thrive being packed closely together with other plants.  They are also easy to take cuttings from, so you can have a whole batch of new geraniums in 8 weeks.

There are hundreds of pelargoniums varieties and they are divided into groups: Angel Pelargoniums, Decorative Pelargoniums, Double Zonal Pelargoniums, Dwarf Pelargoniums, Dwarf Stellar Pelargoniums, Ivy-Leaved Pelargonium, Miniature Zonal Pelargoniums, Scented-Leaved Pelargoniums – just to name a few.

Great combinations are pelargoniums and lavender for fragrance; Pelargonium, euphorbia and salvia; Pelargonium, nemesia and diascia

Penstemons

Flowering time: June – October 

Penstemons give a garden colour right through to late autumn, producing foxglove-like flowers adored by bees and other pollinating insects. Penstemons can grow to 40″ and sit well in the middle of a border, though they may require support from canes if planted in a wind-exposed position.

Penstemons are relatively easy to grow with a little care and attention. Once planted in spring, they do like to be fed with rotted manure and watered/fed regularly. Flowers are prolonged by deadheading.

Penstemons may not survive a harsh winter, so take some softwood cuttings during the plant’s growing season.

Penstemon varieties include: ‘Osprey’, ‘Raven’, ‘Stapleford Gem’, ‘Sour Grapes’, M. Fish,’ Apple Blossom’, ‘Andenken an Friedrich Hahn’,’white bedder’ and ‘penstemon czar’. We currently have ‘Penstemon laura’ with white tubes and pink edges.

Catmint (Nepeta)

Flowering time: June-October

Catmint will start flowering in early summer right through to November under the right conditions – the trick is to cut back stems that look faded, and the plant will flourish. Nepeta will prove essential nectar for bees still out before they die off.

Nepeta like a sunny location and well-drained soil but can survive in dry conditions – they are low maintenance and can easily be divided up if they get too large for your location.

Nepeta varieties include: Select Blue Catmint, White Cloud Lesser Calamint, Walker’s Deep Blue Catmint, Walker’s Low Catmint, Nepeta Six Hills Giant, Nepeta Kubanica

Buying sterile (no seed) varieties is recommended to stop the plant from taking over. They combine well with Salvia, Achillea and Valerian.

>> 15 Best Plants for Full Shade

Astrantia (Masterwort)

Flowering time: June to September (if cut back after first flowering)

Astrantia is a long flowering perennial; easy to grow in sunny or partial-shade positions are not fussy about soil PH.  Astrantia also provides good foliage interest, which is slug and snail resistant.

Like Nepeta, Astrantia is adored by bees. Check out my Tiktok video from last summer, where bees are gorging on nectar then falling asleep on the flowers > https://www.tiktok.com/@plantsman.io/video/7109089807514569990.

To encourage continual flowers over the summer, deadhead regularly; this also stops the plant from seeding, which can be a problem.

Astrantia varieties include: ‘Star of Fire’, ‘Madeleine-van-Bennekom’, ‘Bloody Mary’, ‘Claret’, ‘Margery Fish’, ‘Alba’, ‘Burgundy Manor’, ‘Superstar’. If you are looking for interesting foliage, try the ‘Sunningdale Variegated’.

Astrantias combine well with Geums (see below) and Salvias if you match up your colour schemes.

Erysimum Bicolor ‘Bowles’s Mauve’

Flowering time: All year if you live down south

This wallflower is a perennial Erysimum; most Erysimum is biennial –  meaning they flower every other year.

Wallflowers generally don’t like rich soil; this will decrease the number of flowers you get and give you more foliage. The plant prefers a full-sun location but can still provide a long flowering season in partial sun.

The Bowles’s Mauve is classed as semi-evergreen and has the potential to hold its foliage over winter if freezing temperatures are not prolonged.

Growing to the height of 60cm, the heavily scented flowers are loved by bees and butterflies and work well in the middle of a border.

Perennial Erysimum varieties include: Erysimum ‘Winter Joy'(lilc flowers with early flowering in Feb), Erysimum ‘Winter Light'(yellow flowers), Erysimum ‘Winter Orchid’ (orange flowers changing to purple in later summer months).

Campanulas (Bellflower)

Flowering time: May-October

These plants are part of the Campanulaceae family and come in many varieties. Many are small creepers, like Campanula poscharskyana,  commonly lurking in shaded areas and spreading in wall cracks.

Campanulas do not like harsh winters and will thrive (and spread) in sunny conditions. The deciduous campanula varieties are the

Campanulas varieties include: Campanula rotundifolia, Campanula Alba, Campanula portenschlagiana, Campanula glomerata, Campanula latifolia, Campanula persicifolia, Campanula Loddon Anna, Campanula Stella, Campanula lactiflora, Campanula poscharskyana, Campanula Sarastro, Campanula pyramidalis, Campanula carpatica

Geums

Flowering time: April to October

This is one of the few plants that can give you 7 whole months of flowers if they have the right conditions.  Geums generally like moist soils and partial shade, though some varieties will thrive in the shade, like Geum rivale – I have one in a pot that only gets 1 hour of sun per day and is fine. Larger varieties tend to like more sun-like Geum ‘Mrs J Bradshaw’.

Geums also have great height, reaching up to 60 cm tall, so sit well in the middle of a border and give foliage interest in winter. They will spread using rhizomes so best to divide up and move some every couple of years, depending on your arrangement.

Geum Varieties include: Geum ‘Custard Tart’, Geum ‘Roger’s Rebellion’, Geum ‘Scarlet Tempest’, Geum ‘Baked Beans’, Geum ‘Mrs J Bradshaw’, Geum ‘Totally Tangerine’, Geum ‘El Wano’, Geum ‘East of Eden’, Geum ‘Turbango Twister’, Geum ‘Centurian’.

Long Flowering Plants FAQ

Do any plants flower all year round?

It’s very rare for a plant to flower all year due to the energy required to produce flowers.  Saying that, Erysimums can flower for 12 months, and most varieties will give you colour from spring to the first frost in winter.

What is the longest flowering annual plant?

Pelargoniums will flower all season from spring to winter, and they will only die off when the first winter frost arrives.

Gareth James

Gareth is the owner of Plantsman Media.  Gareth lives in the North East of England and is obsessed with flowers. He has just started RHS level 2 certification.