Desert plant around Connecticut (America) (6)
I believe the answer is:
Here is my best explanation:
'desert plant' is the definition.
(I've seen this before)
'around connecticut america' is the wordplay.
'around' becomes 'ca' (circa).
'connecticut' becomes 'ct'.
'america' becomes 'us' (abbreviation for the United States).
(Other definitions for cactus that I've seen before include "Spiney plant of dry regions", "Spiky desert plant", "Spiny plant of dry regions", "Prickly desert plant", "Succulent plant of arid regions", "Spiny desert plant", "Succulent desert plant", "Drought-resistant plant", "Spiney plant of arid regions" and "Eg, prickly pear".)