Swede possibly excited to make unexpected appearance (4,2)
I believe the answer is:
crop up
'to make unexpected appearance' is the definition.
I can't judge whether this defines the answer.
'swede possibly excited' is the wordplay.
'swede possibly' becomes 'crop' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'excited' becomes 'up'.
'crop'+'up'='CROP UP'
Can you help me to learn more?
(Other definitions for crop up that I've seen before include "Occur unexpectedly - as part of harvest?" , "Appear unexpectedly" , "Happen" , "Occur by chance - like harvest?" , "Occur, arise" .)