Flowers one picks up (6)
I believe the answer is:
irises
'flowers' is the definition.
(type of flower)
'one picks up' is the wordplay.
'one' becomes 'i' (Roman numeral).
'picks up' becomes 'rises' (I can't justify this - if you can you should believe this answer much more).
'i'+'rises'='IRISES'
Can you help me to learn more?
(Other definitions for irises that I've seen before include "Expensive painting" , "Eye membranes or showy flowers." , "Flags" , "Subject for van Gogh" , "Parts of eyes or flowering plants" .)