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The Blues

A vintage park bench painted a powdery blue matches Huguette Fleurie's blue border in her aptly-named garden, Hortensia, in New Zealand. Photo - Linda Ross

Gardeners the world over love blue flowers. Think delphinium, salvia, aster, larkspur, pansy, iris, bluebell, hyacinth, lobelia, veronica and ageratum.

Sandra Ross sings the praises of the blues, and finds inspiration from fine gardens around the world for using azure, cornflower, powder, navy, violet, lavender and mauve in our planting palettes.


Irish Blues

One of my favourite gardens is Helen Dillon’s lovely place in Dublin where she has made a gorgeous blue border. Yet she says the reality never met her expectations: “it never looked quite blue enough.” That’s because there are not that many truly blue flowers and Helen has to be content with mauve and lilac creeping into her blue border. The bluest blue is ‘delphinium’ blue. “Delphiniums are unequalled in summer,” says Helen. “No other plant has such miraculous presence, such celestial spires and such a tiresome list of requirements!” They need protection from queues of slugs, require stakes to keep them upright, and are greedy feeders hungry for handfuls of chicken manure pellets. Helen cuts them to ground level as soon as the first flowers fade, and they re-bloom in autumn.


Delphiniums. Photo -


While the delphiniums are in their autumn blue period, Helen plans more blue for spring by sowing cornflower seed. She sows into trays, then pots up the seedlings and grows them in her greenhouse through winter, before planting out in May. They are sprinkled through her blue spring border to fill gaps left by tulips, “giving a pointillist effect of bright blue”.


Marlborough Blues

On the other side of the world, Huguette Fleurie is another gardener with a penchant for blue. Huguette gardens in the rich, moist soils of the Marlborough region of the south island of New Zealand. Hydrangeas love this climate and grow so well that Huguette named her house ‘Hortensia’, after them. They create a blue haze through this exquisite garden, making a visual link with the agapanthus that line the driveway and stream. The ‘Monet-style’ bridge is painted blue to match, as is the outdoor furniture and the trim on her pretty Victorian house.


Swedish Blues

Hydrangeas are also used to brilliant blue effect in the Jubilee Garden at Sofiero in Sweden. This was one of the Swedish royal families country estates. Masses of blue and white hydrangeas curve through the Jubilee Garden, complemented by deep rose astilbe, lime-green sedum, feathery grasses and violet verbena. The mass of flowering reaches its sublime peak in late summer. The Pleasure Garden at Sofiero also plays with blue. This garden is a formal layout of intersecting squares outlined in buxus. These are planted with a romantic mix of colourful blue flowers, blended with violet verbena, mauve heliotrope, and white gypsophila.


Blues for cool climates - true blue Tibetan poppy (Mecanopsis betonicfolia). Photo - Science Photo Library/


Highlands Blues

Closer to home, Dominic Wong threads blue flowers all through his garden ‘Chinoiserie’ in the southern highlands of NSW. “Blue adds peace and space in any planting composition,” says Dominic. “To create this sense of peace with my pink roses, I use nepetas, Lavendula 'Hidcote', Salvia nemorosa, Salvia gauranitica and Gentian sage (Salvia patens). Blue can add depth and distance and lengthen the view, so you can plant blues at the end of the garden to make it appear longer than it really is. Blue can also be sharpened by white and silver. For this, I use Salvia chamaedryoides, which is a groundcover with silver foliage and dark-blue flowers, Russian sage (Perovskia atriplicifolia), Aster 'Monch' and silvery lambs’ ears (Stachys byzantina). Blue is also great as a contrast against yellows and orange. I like blue agapanthus together with yellow and orange dahlias and Canna 'Bengal Tiger'.



Blue geranium (Geranium pratense). Photo - Juliette Wade/

Home Blues

In my own garden my favourite blue flower is the beautiful tall bearded iris called ‘Victoria Falls’. This iris is one of a few varieties that flower in spring, re-bloom late in summer and then again in autumn. I have it planted in a river-like drift through the central part of a wide garden bed. There are hundreds of varieties of this huge genus but this one is exceptional.

Also well-suited to hot dry gardens is the family of salvias, many of which are blue. They grow as indispensible fillers in my own garden and flower freely through summer and autumn. ‘Mystic Spires’ is one of the classic, versatile varieties, a compact form growing to 45cm. ‘Limelight’ is taller, with felted blue-green foliage and chartreuse bracts clasping the deep blue flowers. All salvias love the sunshine and respond well to pruning. Salvia uliginosa, the bog sage, is another well-worth growing.


Salvias come in a range of blue and purple tones and flower through summer and autumn. Photo - Richard Felber/

Blue combines and harmonises with many colours. Mix it with green for a watery feel or use it to cool down hot red and orange. Focus attention by contrasting blue with yellow. Lime and chartreuse foliages look especially good with blue. Euphorbia (spurge) is one of the best; one called ‘Blue Peaks’ has powder-blue foliage and large chartreuse flower heads. It grows as a handsome round shrub to 50cms, loves sunshine and tolerates drought and frost. You could also try mixing dark blue or navy flowers with white for a crisp, fresh look. However you do it, we’re sure you’ll love playing the blues!


Favourite blues


Scilla hispanica

Description: spring flowering bulb with spikes of blue bell-shape flowers.

Size: flowers spikes grow to 20cm tall.

Special Comments: plant in autumn, 6cm deep and 6cm apart in light shade. Leave undisturbed to naturalise beneath trees for a 'woodland' planting style.

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Salvia ‘Mystic Spires’

Description: a compact evergreen perennial with dark grey/green foliage and upright spikes of vibrant blue-indigo flowers from spring to autumn.

Size: 60 x 45cm.

Special comments: one of the most heat and drought tolerant plants. Needs full sun. Cut it back hard in mid-summer to encourage another flush of flower.


Photo - Linda Ross

Butterfly Bush

Buddleia davidii ‘Black Knight’

Description: a deciduous shrub with an arching, spreading habit. Dark blue/violet flowers are fragrant, and very attractive to butterflies

Size: 2.5m tall if not cut back in late winter; 1.5m tall if cut.

Special Comments: easily grown in average, well-drained soil in full sun. Cut back to the ground in late winter to encourage vigorous growth with better shape and bigger flowers. Remove spent flower spikes.


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Iris ‘Victoria Falls’

Description: a tall bearded iris with soft grey/green foliage and light-blue, ruffled petals, each with a white patch.

Size: clump will stand 0.5m tall and spread to 0.5m.

Special comments: repeat flowering, often producing 14 flowers per plant. Plenty of sun and well-drained soil with a pH near neutral are required.

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Hydrangea ‘Endless Summer’

Description: deciduous shrub with large mid-green leaves and pink flowers in alkaline soils; blue in acid soils.

Size: 1.2m x 1.2m

Special comments: large mophead flowers are produced on new wood. Remove spent flower heads to encourage new ones. Prefers semi-shade and protection from hot, drying winds. Will tolerate some dryness once established. Good for pots.


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Centaurea cyanus

Description: an intensely blue, small, thistle-like blossom floats above sparse, narrow, grey-green foliage.

Size: 0.5 - 1m

Special Comments: cornflowers like to grow in well-drained soil in full sun. They grow easily from seed sown in autumn. Sow seed direct into the garden bed. Willowy stems need to be well supported and look good with nasturtium and marigolds.


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Text: Sandra Ross 

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Author: Sandra Ross