Dead flowers still firing salvos

To my surprise, given I hardly noticed them until I worked at Kew Gardens between 2011 and 2013, Salvia is becoming a Talking Plants favourite. I put it down to a mix of beauty, oddity and pervasiveness. They are not quite everywhere but you do find them here and there.

Today's salvo about salvias is all about one that caught my attention in late August, growing in our border beside the Government House fence. Walking past it in early September I thought the flowers must have been long finished, or perhaps we'd had a frost in Melbourne Gardens despite our climate-change induced almost total lack of them these days.

This is the unassumingly named Brown Salvia, or sometimes Beach Salvia, Salvia africana-lutea. And it does indeed have brown flowers - from a distance looking like like a flowering Gorse Bush past its prime.

When you look closely there are still new flowers being produced but all open flowers are rusty orange or brown, and apparently dry and papery in texture. Dead looking. 

All emerging buds, though, are pale yellow. Alive looking.

So, are the brown flowers alive in the sense of helping the plant to reproduce? Are they attracting pollinators, firing off pollen and receptive to incoming germplasm, or are they the dregs of something that happened back at the bud stage?

It seems the answers are yes to these questions. I couldn't find any yellow coloured flowers open to the world so all the action happens after they turn brown. And while brown, the flowers produce 'a lot of sweet nectar which attracts bees and moths, and acts as an essential food supply [in it's homeland of South Africa] for sunbirds'. Brown Salvia is also host plant for various butterfly species, including in Melbourne this unassuming white one.

In terms of aesthetics, the layer outside the petals (the bits that turned from yellow to brown), the calyx, turns papery and becomes more arousing than the dead-looking flowers - presumably this time to seed distributing animals as well as the odd-plant-enthusiast. This next picture (taken in mid-September) shows the calyx turning red as the ovary in the middle develops into a fruit, and the next (taken in mid-October) has the fruits swollen to pea shape and size.

The species is also grown for its aromatic foliage. To me it has a soft, mildly minty, cut-grass smell. Apparently this is an attractive odor and the dried leaves end up in tea and potpourri.

A selection from the stunning botanic garden in Cape Town, Kirstenbosch National Botanical Garden, is sold under the name of Kirstenbosch Golden Salvia (Salvia africana-lutea 'Kirstensbosch'). It is apparently 'more vigorous ... and often grows larger' than the typical wild form.

In South Africa Brown Salvia clings to the edge of the Cape, sometimes growing on coastal sand. Hence the name Beach Salvia, as well as Dune Salvia and, in Afrikaans, Bruin of Sandsalie.