There are some references to local South African plants. It is a flower like plant high in vitamin C. This is what Wikepedia says:
Waterblommetjiebredie is a
stew. The name comes from the
Afrikaans language and literally means 'small water flower stew'. It is made of meat, typically lamb, stewed together with
Aponogeton distachyos flowers (commonly known as Cape pondweed, Cape hawthorn or Cape asparagus), which is found in the dams and marshes of the
Western Cape, South Africa. The buds (
waterblommetjies) are usually ready to be picked in the southern midwinter months of July and August.
The taste of the stew has been described as much like stewed green beans with a hint of pumpkin.[
citation needed]
Waterblommetjiebredie is a well-respected local delicacy in South Africa and popular with foreign tourists.[
citation needed]
Maybe a substitute would be green beans with some small chunks of pumpkin or butternut squash. Fiddleheads maybe, not the same taste but a similar type of plant.
I'll see if I can contact the author in another forum and see what they suggest.