Purple patch

Sunday, 26 October 2014

The climber Petrea volubilis is in bloom now

I was simply enjoying my good fortune of having lots of purple flowers in my late spring garden, but when I stopped to think about it, I realised the word 'purple' covers a wide spectrum of hues! The colour termed 'purple' is a secondary colour (and strictly speaking it is 'violet') that falls between the primary colours of red and blue on the colour wheel, but we also tend to call 'purple' the tertiary colours formed as it transitions towards red on one side and blue on the other side. The tints and shades form by adding white or black to these three hues (and all the gradations between them) mean that there is a multitude of purple possibilities.

Salvia Purple Majesty

I find it quite hard to know exactly what the colour pure violet actually is, but maybe a flower out at the moment that comes closest to it is Salvia 'Purple Majesty', which has just started its long period of bloom. Being the darkest of the saturated colours, violet flowers benefit from lighter, brighter neighbours, such as silvery Plectranthus argentatus, or paler unsaturated tints of itself, such as lilac and lavender. In my garden at the moment, these pretty pastels are found in the delightful climber Petrea volubilis (pictured at the start of the blog) growing on a pergola, with trusses of simple violet flowers held within cross-shaped lilac calyces, which persist long after the flowers have fallen. This is the first year mine has bloomed properly, and it is providing much enjoyment.

Tall bearded Iris in bloom in my garden

Other flowers of a similar hue out now are Tulbaghia violaceae and a pretty bearded Iris (pictured at left). The Tulbaghia will continue to flower until late autumn. The irises, on the other hand, don't bloom for very long in Sydney, but they do provide some gorgeous colours for creating pictures in the garden. Though I prefer plants that bloom over many months, it is also nice to have some flowers that come and go, providing highlights that can be appreciated all the more because they are transient.

Perennial form of Ageratum houstonianum

Saturated blue-violet (sometimes called 'indigo' by colour theorists) is an elusive hue in my garden; maybe Salvia 'Indigo Spires' comes closest to it, and I do have some pastel-coloured flowers that seem to be tints of this hue. A perennial form of Ageratum houstonianum is just beginning its long blooming season, with its strange fluffy inflorescences. This plant has been the subject of a lot of tip-pruning over the last few months and the result has been a nicely shaped, compact specimen. Campanula flowers often seem to fall in between blue and violet, and the spires of Campanula rapunculus are providing lots of colour now. I enjoy these pastel colours next to strong, bright pink hues, such as those provided by Salvia 'Joan' and a vigorous Dianthus, as well as with clear blues.

Salvia Love and Wishes

The addition of red pigment tips violet towards the hues known as purple and magenta: warmer than the straight violet or blue-violets. My new favourite Salvia - a cousin to 'Wendy's Wish' and 'Ember's Wish' called 'Love and Wishes' - has flowers of this colour, held in sultry dark calyces, and it has not stopped blooming since I planted it in April. The flowers are very similar to those of Salvia 'Desley' but its form is much more compact, and it grows to around 80 cm. It seems just as good a plant as 'Wendy's Wish' and 'Ember's Wish'.

Geranium phaeum Samobor

Adding white to red-violet gives mauve, and I have a few examples of this colour at the moment. One is the climber, Clytostoma callistegioides, sometimes known as the violet trumpet vine, which has trumpet-shaped mauve flowers and is quite spectacular when fully out - and grows well in our climate. Darker shades of red-violet are quite thrillingly dramatic, and I have self-sown Aquilegia hybrids in this colour, along with the flowers of Geranium phaeum 'Samobor'.

I think that flowers of all the variants of what we might call purple - violet, blue-violet and red-violet, in their saturated and unsaturated forms - look fabulous growing together, as well as with cool pinks and blues, and with silver and/or dark purplish foliage. I have found that the purchase of an inexpensive colour wheel from an art supply shop has been a great help in understanding the hues of flowers in my garden - and how they can best be combined!