Salvias have comprised one of the grand plant passions of my life. I took to them in the early 1990s when I became disillusioned with trying to grow cool-climate perennials in my Sydney garden in order to create a cottage-y style. There were a few salvias around in nurseries at that time and I loved their long flower spires, which in a moment of epiphany, I realised could give me something of the 'look' that I craved, using plants that liked the Sydney climate. Since then, there has been an explosion of the number of Salvia species and cultivars available to us.
Salvias comprise one of the largest genera in the plant kingdom - there are more than 900 species of them, and many cultivars and hybrids. They are hugely diverse in size, flower colour, texture and shape. They range from groundcover plants and perennials to quite huge shrubs, with flower colours in almost every hue, including black and brown. They have some of the most brilliant blue flowers in the plant kingdom and some of the most vibrant reds, as well as many shades of pink and purple, white, yellow, violet, cerise, mauve, burgundy, salmon, apricot and orange. Many of the colours are bold and strong, but others are more refined and pastel.
Many have scented leaves - pleasant or otherwise! Salvias can be quite tactile - leaves and flowers can be hairy or velvety, or shiny and smooth; some flowers are very sticky; some leaves can be quite corrugated and rough. Salvia flowers are generally of a two-lipped tubular form and these two lips are usually of unequal length. The flower is held within a calyx that can be a similar colour to the flower or in some cases a contrasting colour which complements the flower. The blooms are usually held in long graceful spires, which contrast well with other flower shapes.
There are various different types of salvias. The herbaceous perennial salvias seen in all the English gardening books, with a basal rosette of leaves from which arise the flower spikes - such as Salvia pratensis, Salvia x superba, Salvia x sylvestris and Salvia nemorosa from Europe and Asia - don't do very well in Sydney (except in a few elevated suburbs or in the less-humid north-west Hills District) and are generally more suited to cooler gardens such as in Melbourne, the Blue Mountains or country NSW. There is one exception to this that I find quite successful in my garden: Salvia forsskaolei. It is a Mediterranean plant with a low clump of large, hairy leaves. It sends up 80 cm spires of purplish-blue or white flowers throughout summer and autumn and can grow in sun or shade. It seems to cope quite well with dry conditions but looks at its best with regular watering.
Recently, I discovered that many of the salvias I grow that I have always regarded as being 'shrubs' are classified by many salvia experts as 'herbaceous perennials'. They are a different sort of plant than the ones just described, however: they do grow into a shrubby, woody form over the warmer months, yet these substantial stems actually need to be cut back right to the ground once the fresh new growth appears at the base of the plant, otherwise the plants will look hideous. A classic example is Salvia leucantha, which has purple or white blooms from late summer all through autumn, held in velvety calyces. Pink- and white-flowered versions are also available. Other salvias that need similar treatment are 'Phyllis' Fancy', Salvia madrensis, Salvia elegans 'Golden Delicious', 'African Sky', 'Meighan's Magic', 'Anthony Parker' and 'Waverly'. I cut my specimens of these back to the ground quite a few weeks ago as soon as the new growth was apparent. I have found out that my Salvia guaranitica Large Form also falls into this category - I always treated it like a shrub and just trimmed it back but this year I have cut all the old woody stems to the ground and am hoping that it performs better as it has been languishing for a few years! I also prune 'Joan', Salvia mexicana Lime Calyx, 'Josh' and 'Indigo Spires' in this way, even though there isn't complete agreement among the pundits as to whether these are shrubs or perennials!
There are true shrubs among salvias, of course. The most compact are the small-leaved Salvia greggii, Salvia microphylla and the hybrid of these two species, known as Salvia x jamensis. In my experience, Salvia microphylla and Salvia x jamensis are the most successful in Sydney. (I find Salvia greggii cultivars don't perform all that well except in areas with less summer humidity.) There are plenty of choices in nurseries these days. My personal favourite cultivars are 'Angel Wings', 'San Carlos Festival' and 'Mesa Azure'. I now prune these salvias in late May, cutting back by about third to a half. In colder areas, it is probably best to delay the pruning till late winter.
Shrubs from very dry regions of the world, such as California, South Africa and the Mediterranean don't like the humidity of our late summer weather in Sydney, though there are a couple of exceptions, and they can do well in the Hills District. These plants perform best in areas of low humidity, such as inland NSW. I don't try to grow any of these now. The very best ones for Sydney I think are the semi-tropical shrubby or semi-shrubby forms - many being quite substantial plants. They come from South America, Central America, Mexico and Texas. Many are incredibly long flowering, over many months in a lot of cases. Most of them are frost-sensitive to a greater or lesser extent. In frost-prone gardens they may be nipped back in winter, but they will survive the sorts of frosts experienced in Sydney, especially if there is overhead tree cover to provide a bit of protection. They form a woody frame and are generally cut back pretty hard in late winter (and sometimes again in mid-summer to control their size, as some can get rather enormous). I have given up growing most of the really big ones (due to lack of space!) but some the taller ones that I do still have in my garden are 'Timboon', 'Omaha Gold', Salvia gesneriiflora, Salvia roscida, Salvia elegans Purple Form, Salvia dorisiana, 'Desley' and 'Amistad' (though some regard this as a herbaceous perennial and cut it to the ground each year!). I only cut back the winter- and spring-flowering specimens back after blooming is complete, usually in late spring. More compact shrubby salvias include the 'Wish' series, Salvia 'Van Houttei', Salvia 'Ellie' and Salvia miniata. I trim these back by about half in late May. Leave till late winter in colder areas.
Yet another group comprises the so-called 'annual' salvias - Salvia farinacea, Salvia coccinea and Salvia splendens - all these do well in Sydney and often will live for a couple of years or will self-seed and so appear year after year - they are really bushy perennials in their native habitats, so just need to be cut back by half in late winter!
19 Sep 21
Meet some of the ferns that grow well in Sydney,
A garland of daisies
12 Sep 21
Daisies seem to epitomise spring and there are lots to choose from for Sydney gardens.
05 Sep 21
September sees some beautiful and easy-going shrubs come into bloom in Sydney.
Borage and kin
29 Aug 21
The herb borage has some easily grown relatives.
22 Aug 21
Many plants need rejuvenation after a few years.