Sturt’s Desert Pea (Swainsona formosa) is one of the iconic plant species of inland Australia, and is the floral emblem of South Australia. In the wild it can produce massed displays of extraordinary scarlet flowers, usually having a glossy black central boss.
The photograph on the front cover, taken in August 2006, shows one such display in the Cape Range National Park in Western Australia. It is worth noting that many populations in that park lack the glossy black boss on the flowers.
It is reputed to be fairly easy to cultivate in hot climates. I guess it has been cultivated in Britain occasionally, though I am not aware of any reports of this. It seemed to be an interesting challenge….
I bought a small packet of seed in Australia in 2006, and decided to give it a go this spring. The seed germinated well and rapidly using the bog method on an indoor windowsill, without any pre-treatment of the seed, following sowing on 5th May. The young seedlings transplanted well into a peat-based compost containing 30% perlite, and grew on in the greenhouse. Then slugs discovered them (even in the greenhouse!). I transplanted the surviving plants into 2 litre pots (both clay and plastic) containing a similar, well-drained, soil-free compost. The plants that had survived the slugs grew well initially, but many succumbed to root rots in the dank conditions in July and August. Two plants initiated flower buds during August, and one of these flowered in early September. This plant made a spectacular display on our kitchen windowsill before it too succumbed to a root rot. These flowers too had paler bosses than normally seen in the wild, but the red colouration was superb.
With hindsight, and having read more on the cultivation of this species, I may have achieved better results had I used a free-draining inorganic compost at transplanting. And I am sure I would have seen better growth had there been more sun this summer! Nevertheless, my experience does show that Sturt’s Pea can be grown to flowering fairly easily, and I’ll try again.
Author: John Purse
Published: Issue 41 (December 2008)