Dennis Norgate grew the Prairie Sage, Salvia azurea, for decades when he ran his justly renowned Norgates Plant Farm just outside Trentham in the central highlands of Victoria. I got it off him more than forty years ago and have always found a spot for it in the garden, sometimes planting large patches sometimes just the odd plant.
This Salvia has a wide distribution in the USA, from Nebraska to Colorado, Texas to Kentucky. It was early introduced into English gardens where it was well established by 1840 although it was then more often grown in glass houses than in gardens because of its late flowering habit.
The flowers of Salvia azurea, blue like the Aegean on a clear summer’s morning, are carried on 90cm long lax stems each with twenty or more large blooms open at once. It’s impossible to make Prairie Sage neat and tidy as it is in its nature to loll around. Staking doesn’t help as all it does is make the plants look awkward and gangly. Whilst many Salvias are drought tolerant this one isn’t and it always needs extra irrigation during summer if it’s to flourish.
In the vegetable garden we have double flower borders, each some fifty metres long by 3 metres wide, lining the central path. We plant these beds with brightly coloured annuals, bulbs and perennials mostly in bright oranges, reds and yellows with some touches of clear pink, gentian blue and soft peach. I usually let nasturtiums trail onto the path but this year planted Salvia azurea along the sides of both beds with each plant placed close to the path so that they would spill forward onto the gravel. It started flowering in early March and is still incredibly beautiful as I write in mid-April.
Salvia azurea is herbaceous, that is it dies to the ground during winter and reshoots the following spring. A lot of gardeners, especially those new to the craft, struggle with the idea of herbaceousness and prefer to plant evergreens not realising what an advantage it is to have herbaceous perennials in the garden as it allows the under planting of spring flowering bulbs. The bulbs grow, flower and make new bulbs whilst the perennials are hibernating and when the bulbs are finished their work the perennials can take over the space again.
Many of the North American sages are at their best in April, at least here in Central Victoria. Hot summer days mean that there are rarely more than one or two flowers open on each stem at any one time as the heat shortens the life of each bloom. Cooler weather in autumn allows each individual flower to last much longer so that there are many more flowers open on each stem at once. As most Salvias make more and more flowering stems as the season goes on the display gets finer and finer until the first sharp frost comes along.
Salvia leucantha, its clones and hybrids, are amongst the best of all perennials for autumn display. For many years we had to do with two varieties, Salvia leucantha with whitish flowers from fuzzy purple-mauve calyces and Salvia ‘Midnight’ with mauve flowers from the same coloured calyces. Both grow 150cm tall by as much across in good soil. A dwarfish form, Salvia ‘Santa Barbara’, was introduced from the USA a few years ago. In my garden it makes 100cm in height by 120cm wide.
The showiest of all this species though is one I found growing in an old garden in Melbourne. A long-dead senior gardener from the Melbourne Botanic Gardens had lived there and I can only guess that Salvia ‘Harry’s Red’ is an old clone which had been long lost to the nursery trade or maybe it was a sport of Salvia ‘Midnight’ which had just cropped up in that garden. Be that as it may this is the brightest of all Salvia leucantha clones with its purple calyx and a bright purple-red flower. It has made a dense floriferous plant some 150cm tall by 180cm across in our new Mediterranean garden. If I sit quietly I often see it shiver as a family of New Holland Honeyeaters feasts on its nectar.
Two other varieties recently came to Australia from South Africa and they are astonishingly different from all that had gone before. It’s hard to understand where the genes for the pure white calyces and flowers came from in Salvia leucantha ‘White Velour’. This is a superb flowering plant although not so hardy in my garden where it needs regular replacing. Salvia ‘Pink Velour’ has similar white calyces but the flowers are baby pink.
I cut all Salvia leucantha varieties back to the ground during May as the under planted bulbs are starting to grow and autumn frosts have usually damaged the flowers by then. I live in an area which gets spring frosts well into November so this Salvia rarely gets under way here until December and doesn’t flowers until March. In softer climes, such as Sydney, this plant hardly ever stops flowering but it should still be cut to the ground sometime during winter to freshen it up.
[This is a sponsored post from Lambley Nursery, Ascot, Victoria. Browse Lambley’s full perennial catalogue]