Donkey’s over being attached to sticky part of plant (5)

I believe the answer is:
burro
'donkey's' is the definition.
(term for a small donkey)
'over being attached to sticky part of plant' is the wordplay.
'over' becomes 'o' (cricket abbreviation).
'being attached to' says to put letters next to each other.
'sticky part of plant' becomes 'burr' (I can't explain this - if you can you should believe this answer much more).
'o' put after 'burr' is 'BURRO'.
Can you help me to learn more?
(Other definitions for burro that I've seen before include "Spanish donkey" , "Beast of burden" , "Small donkey used as a pack animal" , "Small donkey (US)" .)
