Which annuals should I grow?

Debi Holland shares her love of garden annuals and suggests five fabulous annuals to grow in your garden

I get tremendously excited about the prospect of sowing annuals. Their explosion of colour injects a much-needed dash of pizzazz into the garden. Annuals are great gap fillers in borders and are a hit with pollinators. These quick-growing, low maintenance, cheap crowd pleasers just require water and sun; Mother Nature does the rest.

Poppy ‘Lauren’s Grape’ with bumblebee pollinator. Image: Debi Holland

So what defines an annual?

Annuals are plants that complete their life cycle from germination to seed, in one growing season, then die so need replanting the following year; although chances are they will have self-seeded. They are one of the easiest groups of plants to grow from seed. Two words of advice; direct sow. Once the soil warms up between March and May, weed and then rake soil to a fine crumb; seedlings struggle to push through thick clods. Firm soil then thinly sprinkle seed; either scatter in drifts or sow in drills for more formality. Cover with a light layer of multi-purpose compost and water. Once germinated thin out seedlings; plants won’t perform well if overcrowded or shaded. Refer to seed packets for plant spacing. Alternatively sow your seed from February/March in individual modules in a greenhouse or cold frame to transplant as established plants later in the season. Hardy annuals can be sown outside earlier than half-hardy which do not tolerate frost.

Annuals provide a fabulous display of colour. Image: Debi Holland

If that all sounds like hard work then buy pre-grown plug plants mail order or from a garden centre for instant results. The secret to successful annuals is plenty of light and deadheading to prolong flowering. You can even save money, collect your own seed in autumn to sow next year! So, what to grow?

Marigolds / Calendula

I grew so many varieties of marigold and calendula in 2018, the ‘Year of the Marigold,’ and was rewarded with a summer of continuous colour. Top marigold performers were ‘Moon’ (swoon!), ‘Kees Orange,’ ‘Sunspot Orange,’ ‘Champion,’ ‘Bonita’ and French Marigold ‘Naughty Marietta.’

Calendula ‘Orange Flash’. Image: Debi Holland

For intense orange calendula flowers grow Indian Prince, Art Shades and Citrus Cocktail. But the overall winner was Calendula ‘Orange Flash.’ What a showstopper. Apricot petals with a richer underside form a bushy display of multiple blooms.


The August garden would not be complete without the long-lasting blooms of sunflowers. Helianthus annus are so easy to grow and provide an ideal opportunity to get children involved in the garden too. Seeing huge smiley faced flowers emerge from a single seed is miraculous; a science lesson in the palm of your hand.

Sunflower ‘Red Sun’. Image: Debi Holland

Start in pots or direct sow; they thrive in full sun, rich soil, spaced 45cm apart and support with bamboo canes. Sunflower seed heads also provide food and habitat for wildlife in winter. I adore the amber hues of ‘Velvet Queen,’ ‘Sunburst’ and ‘Red Sun,’ but if you need height try ‘Russian Giant’ ‘Colossus’ or ‘Skyline.’ Just keep an eye out for hungry slugs and snails.


Poppies, a symbol of remembrance; immortilised in the poem ‘In Flanders Fields,’ are a popular flower in wildflower mixes. Their intense colours and naturalistic spread make them a huge hit with gardeners and pollinators. Field poppy (Papaver rhoeas), Papaver commutatum ‘Ladybird’ and opium (Papaver somniferum) poppies such as ‘Lauren’s Grape’ and ‘Mother of Pearl’ are all outstanding performers.

Californian poppies ‘Orange King’. Image: Debi Holland

I also adore Eschscholzia californica, California poppies. The electric blooms of ‘Orange King’ contrast exquisitely against frothy blue foliage or try ‘Golden West’ as a stunning yellow alternative. They cope well with drought too.


The intricate flowers and spectacular colour palettes of Zinnia elegans make my heart ‘zing’.

Zinnias have exquisite and intricate flowers. Image: Debi Holland

Zinnia make superb cut flowers and look stunning as a single stem in a vase. They have a reputation for trouble. Zinnia are prone to botrytis, powdery mildew and like sweet peas detest root disturbance so try direct sowing instead of individual modules. Thin seedlings to one plant every 30cm to cut out the need for transplanting.

Try ‘Hot mix,’ ‘Purple Prince,’ ‘Whirlygig,’ ‘Envy,’ ‘Orange King’ and ‘Jazz’ or the flamboyant ‘Benary’s Giant Orange.’  

Zinnia ‘Benary’s Giant Orange’. Image: Debi Holland


Nasturtiums (Tropaeolum majus) make a delicious peppery garnish and will certainly brighten up any plate with edible flowers and leaves. Even the young seeds can be eaten green – ‘poor man’s capers.’ They bloom best in full sun and poor soil but most importantly cope well in drought. After last year’s dry summer the search for drought resistant plants has never been so relevant. Give them space to romp around, they like to spread, great for ground cover but may need reigning in! They readily re-seed so are likely to reappear. Short for space? Try ‘Tom Thumb’ an excellence dwarf variety bearing single brightly coloured flowers. Ideal for pots. I adore the marbled foliage of ‘Alaska,’ which contrast beautifully against the bright orange flowers. Lastly, two ‘must have’ cottage garden annuals are cosmos and sweet peas. Both featured in articles: Growing cosmos for cut flowers and How do I get the most from my sweet peas?

Nasturtium ‘Alaska’. Image: Debi Holland

Get 10% OFF your first order

Be the first to get our latest special offers, gardening tips and news. Sign up and get 10% OFF your first order!

This field is for validation purposes and should be left unchanged.

The home of Flower Power

Over 1,000,000 sold worldwide

Tried, tested & trusted

Professional formulas made for all

Over 50 years experience

Tried, tested & trusted garden care

Used by award-winners!

Over 100 golds won at garden shows

Find out more >