Plant available, one found in South Africa (7)
I believe the answer is:
freesia
'plant' is the definition.
(freesia is a kind of plant)
'available one found in south africa' is the wordplay.
'available' becomes 'free' ('free' can be similar in meaning to 'available').
'one' becomes 'i' (Roman numeral).
'found in' means one lot of letters goes inside another.
'south africa' becomes 'sa' (abbreviation).
'i' put into 'sa' is 'sia'.
'free'+'sia'='FREESIA'
(Other definitions for freesia that I've seen before include "Fragrant-flowered plant; faeries (anag.)" , "Highly scented flower" , "Plant of the iris genus" , "Flowers for strange faeries" , "Fragrant flower (sounds rather cold?)" .)