Mom is high, on top of a tree (6)
I believe the answer is:
mimosa
'tree' is the definition.
(mimosa is a kind of tree)
'mom is high on top of a' is the wordplay.
'high' indicates anagramming the letters (can mean drunk or on drugs and hence disordered).
'on top of' is a charade indicator (letters next to each other).
'mom'+'is'='momis'
'momis' with letters rearranged gives 'mimos'.
'mimos'+'a'='MIMOSA'
(Other definitions for mimosa that I've seen before include "Sensitive tree or shrub with globular clusters of yellow flowers" , "One growing sensitive" , "Tree with scented clustered flowers" , "Buck's Fizz" , "Yellow-flowered acacia tree" .)