Poor Russians catching cold in plant (9)
I believe the answer is:
narcissus
'plant' is the definition.
(narcissus is a kind of plant)
'poor russians catching cold' is the wordplay.
'poor' indicates anagramming the letters.
'catching' means one lot of letters goes inside another.
'cold' becomes 'c' (eg on taps).
'russians' is an anagram of 'narissus'.
'narissus' placed around 'c' is 'NARCISSUS'.
'in' acts as a link.
(Other definitions for narcissus that I've seen before include "Vain youth - flower" , "Greek youth who fell in love with his own reflection" , "Reflective chap" , "In Greek myth, youth in love with his reflection" , "Flower of daffodil family" .)