Homeowners are being warned about 27 invasive plant species that could wreck havoc if left to spread in the garden ...

Following recent rains, the Okavango Delta, one of the world's largest inland deltas, which has been going through its driest period in recent years, has sprung back to life.

Half of the lake's surface became covered by the invasive giant salvinia -- Salvinia molesta -- a free-floating plant that has made the lake uninhabitable for both fish and manatees. To combat it ...