The colour blue

Sunday, 27 March 2016

Salvia guaranitica Large Form with Euryops pectinatus daisy in the background

Recently I saw the exhibition Blue: Alchemy of a Colour, at the National Gallery of Victoria International in Melbourne - an exploration of the two most historically important blue colourants: the mineral pigment cobalt (used in ceramics) and indigo, derived from the plant Indigofera tinctoria (used in textiles). Both substances were introduced to Europe in the 16th century. Chinese blue-and-white porcelain was highly prized, and its decorative patterns and compositions profoundly influenced European artwork. Indigo was used over the centuries to colour cloth through the use of tie-dying and wax resists (such as batik). The colour blue is associated with deities in Hinduism and Buddhism, and blue components of garments were thought to enhance the power of the wearers and protect them from evil forces. Blue material was also used for ceremonial clothes to show the rank of the wearer.

Borago officinalis: the herb borage

The beauty of the blue-and-white ceramics and textiles on display (many of them extremely ancient) reminded me of the timeless effectiveness of this crisp colour combination in gardens, and of my fondness for the colour blue in general. In fact, it is probably my favourite hue of all, both in the garden and out of it! I have always thought there was something 'celestial' about the colour; indeed, in Italian the word for sky-blue is celeste! As a child with an overactive imagination, I thought blue flowers were made from piece of the sky, or made by fairies!?

Blue is a 'cool' colour, and it suggests space and distance, as well as freshness and calmness - and perhaps even an element of melancholy. Hot colours such as red, orange and yellow can be tiring on the eyes after a while. It is hard to find flowers that are coloured pure blue: so many tilt towards the purple part of the colour wheel. However, blue retains its character when lightened with white or darkened with black, and I love all its shades and tints. It seems to me that blue flowers mix effortlessly with those of any other colour, enhancing each of them in different ways. Harmonious and dreamy with related cool colours such as violet, purple and soft pinks, blue makes hotter colours such as yellow and orange seem brighter and more excitingly vibrant when it sits side by side with them. I particularly like blue flowers nearby to golden or lime-green foliage, and I also enjoy seeing them with silver or purplish foliage for different effects. This week I wandered around my garden to identify some of my favourite blue flowers.

Browallia americana

Perhaps the bluest of all in my garden is the annual Browallia americana, a truly delightful little plant that entered my garden as a single wilted seedling pulled up by a kind friend from her garden. 'You'll never get rid of it', she remarked, in what sounded a vaguely ominous tone. And it's true; I now have it everywhere through my garden as it self-seeds madly, and I pull up a fair few every year - but I love it more than ever. The seedlings appear in spring and grows to about 30 cm or a little taller. The gorgeous bright blue flowers each with a tiny white eye complement every plant they decide to grow next to. Their ubiquity throughout my garden actually provides a uniting thread! They flower all through summer into autumn, and sometimes new ones appear at that time that carry on until spring. They can be cut back when they start to look straggly and they will rejuvenate. I only pull them out when they have utterly had it. Though they flower best in sun, they do grow quite well in part-shade.

Salvia sinaloensis

Salvias offer some of the bluest of blue flowers, but to my chagrin, I have found that the best of these belong to the most rampageous varieties (think Salvia uliginosa or Salvia guaranitica, including its seductive but wicked cultivar 'Black and Blue') or ones that don't grow that well in Sydney (apart from in the more elevated areas), such as the gorgeous Salvia patens. However, there are some good ones for Sydney, including shrubby Salvia guaranitica Large Form (a non-running type with blooms of a clear royal blue); Salvia sinaloensis, a groundcover with startlingly blue flowers held against purplish-tinged foliage; and Salvia 'Marine Blue', a tough shrublet which has its bright blue flowers from spring until the end of autumn. In general, these plants will do best in a sunny spot.

Ceratostigma willmottianum

A stunningly rich blue flower appearing now in the garden is that of small shrubby Ceratostigma, the so-called Chinese plumbago, which has a couple of species. The simple flowers are enhanced by the autumnal tints of orange and red that some of its own leaves develop at this time of year as the temperature falls. Like many shrubs from China, these are adaptable to cool and warmer climates alike. Actual Plumbago also has pretty blue flowers of different shades, but I am not a fan of this larger shrub, which tends to sucker and spread too much in Sydney gardens.

Hydrangea macrophylla, mophead form

Hydrangeas are another source of blue flowers - as long as you have an acidic soil in your garden: otherwise your flowers will be pink! This also applies to the evergreen cousin of the Hydrangea, called Dichroa, a taller shrub which has domed, clustered flowers in flushes. Sydney has one of the best climates in the world to grow these shrubs, which grow best in a shaded spot. I love all hydrangeas and enjoy their lovely blue flowers in vases through their main blooming period of early summer. There are so many variations in flower form and in the depth of the colour. Blue looks at its most cool in shade, so banks of blue hydrangeas under tall trees can provide a welcome oasis on a hot summer's day, especially if paired with some white flowers to enhance the effect even more.

Borage (Borago officinalis, pictured earlier in the blog) is another favourite of mine, with its clear-blue, star-shaped flowers. Like the Browallia it is a self-seeder; however, I don't mind weeding the extra ones out. I have also always loved the bright blue daisy flowers of Felicia amelloides, but it doesn't like my heavy garden soil and fades away before too long.

Hope everyone is enjoying the Easter break. I'd be interested to know some of your favourite blue flowers!