Help! I need to solve three cryptic clues to flowers, plants, herbs and shrubs, Can you help?

Ive solved all clues but three.


Here are the three clues? Do you know what the answers are?





1) Bill sounds like a nice fellow...


2) Sounds like the first lady prime minister... (something to to with margaret thatcher?)


15) Bovine error...





Please help, Ant...

FlowersBirthday FlowersSympathy Flowerssweet william


marguerite


cowslip
Reply:2) could be a margaurite, please check spelling. this is a half hardy plant which has daisy type flowers in yellow, white or pink shades
Reply:Sweet William


???


Cowslip
Reply:Number one is Sweet William.Number three is cowslip
Reply:sweet william





cow slip
Reply:Sweetwilliam


?


Cowslip





Wild Guess, Blue belle for Margaret Thatcher
Reply:sweet william first one working on the others
Reply:15) is Cowslip
Reply:15) Cowslip


1) Sweet William


2) ?? Might get back to you on this one





Hope I%26#039;m right.
Reply:#1 maybe Sweet William?





#2 maybe de-thaching your lawn?





#15 Bull-S*?% maybe, manure?visual arts