Friend cultivated ideal ornamental shrub (8)
I believe the answer is:
buddleia
'ornamental shrub' is the definition.
'buddleia' can be an answer for 'shrub' (buddleia is a kind of shrub). I'm unsure of the 'ornamental' bit.
'friend cultivated ideal' is the wordplay.
'friend' becomes 'bud' (short for buddy).
'cultivated' is an anagram indicator.
'ideal' with letters rearranged gives 'dleia'.
'bud'+'dleia'='BUDDLEIA'
Can you help me to learn more?
(Other definitions for buddleia that I've seen before include "Flowering shrub" , "flowering plant" , "Butterfly bush" , "Common shrub attractive to butterflies" , "Shrub with clusters of fragrant lilac, white or yellow flowers" .)