Cerise, colour of choice for desert flower and our new logo

July 2008

The natural home of this Desert Rose are arid lands of Africa rather than Australia, but it's growing here in Darwin, the capital city of Australia's Northern Territory.

In case you are confused, the floral emblem of the Northern Territory is Sturt's Desert Rose, Gossypium sturtianum. Proclaimed in 1961, this relative of commercial cotton (Gossypium hirsutum and other species of Gossypium) grows naturally in rocky parts of inland Australia.

The Desert Rose, unadorned by Captain Charles Sturt's commemorative prefix, is an entirely different plant, Adenium obesum. It's in the family Apocynaceae, also home to oleanders and frangipanis.

July 2008

Like many in this family (most notoriously, the oleanders), Adenium species have poisonous white sap. That sap is used in Africa on arrow tips and to poison fish, sometimes laced with extracts from equally toxic species in the genus Euphorbia.

At ground level the trunk and top of the roots are distinctly swollen, forming what is called a caudex. While all parts of the plant are toxic, this caudex is typically harvested then heated to extract the latex. 

The name Adenium refers to Aden, a colonial area and now capital of Yemen, where the first specimens were collected for scientific naming. You can guess what obesum means. It's one of five generally accepted species, which grow throughout Africa and the Arabian Peninsula.

July 2008

The Desert Roses photographed here have pride of place in Darwin's George Brown Botanic Gardens, so you might be forgiven for thinking it was both a local plant and perhaps the emblemic plant of the territory.

Neither plant is a rose of course, but the flowers are bright and cheery, and in a desert setting perhaps the closest thing you'll get to a Rosa.

Most species lose their leaves in winter or the dry season, depending on where they live. In Darwin, the plants were deciduous in July (2008, photographed above) and in leaf in October (2016, next few photographs). Both times, they were in flower  but more so in July (I presume the new leaves followed the flowers).

October 2016

In it natural habitat, extending from the Arabian Peninsula (including the island of Socotra, with so many intriguing plants) down to Somalia, Ethiopia and, south of the equator, Tanzania, as well as westward across the southern Sahara, it is a variable in form. Some are shrubs, like this specimen, others are small trees.

The leafy specimen photographed on my most recent visit (2016) is apparently of hybrid origin, perhaps between a few variants or subspecies of Adenium obesum. It's about 40 years old but was transplanted from Sturt Park in Darwin in 2013. 

October 2016

It seems to have survived and thrived in its new home and is described as the largest in Darwin. I'm not sure what happened to the one I photographed five years earlier, which seemed equally robust.

Let's just focus on those beautiful petal lobes, softly downy and pinkish in colour. Sometimes they are described as cerise, the colour we have introduced into our logo for the 175th milestone year of Royal Botanic Gardens Victoria.