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Helianthus 'Ms Mars' (Sunflower)

Summer flowers: The best summer flowers to plant

Make sure you've got the perfect blooms in the garden for summer. Head gardener Tom Brown picks his favourites. Photographs by Jason Ingram

We’ve picked out a series of flowers to inspire you in the garden centres to make sure your garden looks fabulous this season.

Tulipa clusiana 'Cynthia'
© Bennet Smith

Papaver somniferum ‘Lauren’s Grape’

Papaver somniferum, 'Lauren's Grape'

If you’re going to grow a somniferum poppy, make it this one. Once you’ve tried ‘Lauren’s Grape’ and appreciated its sophistication and sultry, bowl-like, dark-purple flowers, you’ll be forever particular about your poppy selections.  I start seed off early in the year and treat as an annual, although the seedlings will overwinter in free-draining spots. If visitors to the garden don’t relieve me of the blue/green seedheads, they make superb cut flowers to add form to an arrangement; and do save the seed for the following year, once the pods have dried. Height 1.5m. Origin Garden (species from southeast Europe and western Asia). Conditions Well-drained soil; full sun. Hardiness RHS H5. Season of interest Early summer, seedheads persist into winter.


Allium atropurpureum

Allium atropurpureum

This is not one of those alliums that increases each year and clumps up beautifully. However, I can completely forgive it this one fault and happily treat it as an annual
as the intense, dark-purple flowers work so well with perennials at this time of year. You’ll find the bulbs inexpensive and I would suggest planting them in groups of five to seven and work them through clumps of early summer perennials such as artemisia and nepeta as well as with later-flowering perennials such as phlox to give interest and punch in early summer. Height 1m. Origin Hungary to Turkey. Conditions Moist but well-drained soil; full sun. Hardiness RHS H5, USDA 4a-8b. Season of interest Early summer.


Geranium pratense ‘Wisley Blue’

Geranium pratense 'Wisley Blue'

This beautiful form of cranesbill has got some real stature when it flowers, particularly when grown up a domed support of hazel or birch, providing height in the border. Classic, powder-blue flowers are profusely produced in early summer, giving a big burst of colour to mixed plantings. Once the flowers have faded, the plant can be cut to the ground, to enable a fresh flush of foliage to emerge, giving a neat and compact foil for other emerging plants. This, like most geraniums, is very versatile and is quite content in many garden situations and schemes. Height 1.5m. Origin Garden (species Europe and Asia). Conditions Reasonable, well-drained soil; full sun. Hardiness RHS H7, USDA 4a-8b. Season of interest Early to midsummer.


Helianthus annuus ‘Ms Mars’

Helianthus 'Ms Mars' (Sunflower)

Throughout the summer of 2015 I trialled more than 100 different forms of sunflower and became totally enamoured with the dwarf cultivars. These delivered stems that were long enough for cutting but which required no staking. One that stood out from the crowd was ‘Ms Mars’. Its distinct, pink and claret-coloured flowers are produced profusely on knee-high plants. Like all sunflowers, they give a much-needed boost of colour to our gardens when the heat of summer has drawn some of the vim and vigour out of our displays. Height 50cm-1m. Origin Garden origin (species from USA and Central America). Conditions Moist but well-drained soil; full sun. Hardiness RHS H4, USDA 2a-11. Season of interest July to September.


Helenium ‘Sahin’s Early Flowerer’

Helenium 'Sahin's Early Flowerer'
© Jason Ingram

I grow several heleniums but this one stands above all others for sheer flower power. It’s incredibly long-flowering –from July all the way until autumn –beginning life with a strong red and burnt-orange display that rather elegantly fades to a paler orange and yellow colour as it senesces, with the chocolatey brown centres persisting into the winter. This robust form of sneezeweed has the vigour and strength to associate happily with other perennials, grasses and shrubs. AGM. Height 1-1.5m. Origin Garden origin (species from North and Central America). Conditions Reasonably fertile and well-drained soil; full sun. Hardiness RHS H7, USDA 4a-8b. Season of interest Early summer to autumn.

Zinnia elegans ‘Benary’s Giant Wine’

Zinnia Elegans 'Benarys Giant Wine'
© Jason Ingram

I grew a number of taller-stemmed zinnias in 2017, and the ones that stood out head and shoulders above all the others were those from the wonderfully consistent Benary’s range. They are available in a variety of colours, with one to suit almost every taste. This one from the Benary’s Giant Series is a classy plant, with sultry mulberry-coloured flowers. It is perfect grown as a cut flower, but will also have a strong presence in your borders until the first frosts. Height 50cm-1m. Origin Garden origin (species from Mexico). Conditions Moist but well-drained, fertile soil; full sun. Hardiness RHS H2, USDA 9a-11. Season of interest Staggered sowing will produce flowers from July until first frosts.

Helianthus debilis ‘Vanilla Ice’

Helianthus debilis ‘Vanilla Ice’
© Jason Ingram

Sunflowers can be troublesome when  it comes to their heavy flowerheads and can demand strong staking techniques to see them through the latter part of the summer. ‘Vanilla Ice’ is a more delicate, multi-branched individual, and as such is far less demanding.  I grow this highly floriferous cultivar for cut flowers. The stems are wiry  and the flowers are very useful in arrangements with other summer blooms, such as yellow zinnias and blue statice. Height 1-2m. Origin Garden origin (species from USA and Central America). Conditions Moist but well-drained soil; full sun. Hardiness RHS H2, USDA 9a-11. Season of interest July – September.


Watch out for Keith Wiley’s monthly plantsman’s choices.