In order to play Tom Petty's 'Wildflowers' on the ukulele you first have to only know three chords for the whole song's verse and a couple more for the song's bridge. To start the first verse you play a B flat major chord. To play this chord bar the first two strings of the first fret, your second finger on the third string of the 2nd fret and your third finger on the fourth string of the third fret. Next, play F major which is first finger on 2nd string of first fret and the second finger on the 2nd fret 4th string. Last, you play a C major which is simply your first finger on the first string of the third fret. To play the verse play Bb, F, C and then back to F. Now on the bridge you play a Dm and then a G chord. You will go from Bb, to F, Dm, to G and then C for the bridge. Bb, Dm to C then is the end of the song. The strumming pattern is a quick upbeat one. Now, following this chord progression you can play the song! Just practice!