South African Cabbage Trees tolerating centuries of drought in Australian botanic gardens

I'm sure I'd noticed before the Cabbage Tree (Cussonia) outside my old office at the Royal Botanic Garden in Sydney, but it was a pleasant surprise to (re)discover it on my visit there a week or so ago. I was even more pleased to discover first one in the yard of the lodge I'm staying in temporarily at Melbourne's Royal Botanic Gardens and then another rather larger one well within the botanic gardens. 

The species of Cabbage Tree in Sydney is labelled Cussonia paniculata, the one in Melbourne Cussonia spicata. Returning from a walk to the far side of the botanic garden tonight I found another specimen, this time with the same species name as the one I saw in Sydney. 

Here are some more pictures of Cussonia paniculata from Sydney, including one of a flower and perhaps the only pollinator that could love such a flower.

This is the one in Melbourne next to a casually addressed Director on holidays:

So what are these strange and arresting plants? They are in the family Araliaceae - along with ivy and various of the things called Umbrella Trees - and there are about 25 different species. It's their chunkiness and large umbrella-like leaves that make them stand out from the botanical crowd.

The Melbourne specimen of Cussonia paniculata seems to have differently incised leaves to the one in Sydney – they are more what I would call ‘pinnate’, like many ferns. The Sydney one, from memory and my pictures, had fewer segments with saw-shaped edges.

This may be seasonal or age-of-plant variation but my favourite website for African plants, Plantzafrica, mentions two varieties of Cussonia paniculata: the more commonly grown variety sinuata having deeply lobed leaves. I don’t have access at the moment to any technical literature to check this, or indeed to check if the species identifications are correct in the first place. 

Adding to this uncertainty, the plant labelled Cussonia spicata here in Melbourne looks very like the Cussonia paniculata from Sydney. These are pictures of two different specimens in Melbourne, but both clearly the same species. Down here, we seem to call it Cussonia spicata.

Native to tropical and southern Africa, and nearby islands, Cussonia species don’t  mind dry conditions so it suits the planting ethos of most botanic gardens around Australia today.

In fact this has been the ethos of the Melbourne botanic gardens right back to its first curators John Arthur and John Dallachy (1846 to 1857), and first directors Ferdinand Mueller and William Guilfoyle (1857-1909). They all tested the Australian flora to find drought-tolerant gardens plants: Mueller, for example, trialled Blue Gum (Eucalyptus globulus) avenues when the botanic gardens was under his control.

Exotic succulents and other South African plants were early introductions into Melbourne. The largest Cussonia in the Melbourne botanic gardens looks like it might have been a Mueller or Guilfoyle planting. Or indeed both: Guilfoyle famously moved lots of Mueller’s trees to new locations.

I have no doubt there are more of these two Cussonia species in both botanic gardens, and other species, but it's always nice to (re)discover something as distinctive and odd as these South African trees. It might also be nice one day to confirm their identities and get Sydney and Melbourne in sync. Or maybe its just that I'm adjusting to the Australian summer and not taking in the subtle details of the plants yet.