Possible Clues:

• African river
• Flashy car containing Old Man River
• What Kipling thought grey-green and greasy feeble old river
• S. Africa/Zimbabwe border river
• As a river, after half a century I am two rivers
• River that runs through South Africa and Mozambique
• One flower or two attached to fruit, shortly
• River of SE Africa
• Stagger on, with little work and nothing at the end of it? The river!
• River rising as the Crocodile River near Johannesburg