Looks like its been covered pretty well
but just to emphasize... good lure is a must, organic blue magnet is highly recommended. Once you have maxed the blue magnet being organic isn't so important but it will miss every so often and misses can translate to sad pretty quickly.
You can always replant trees anytime you please so don't get hung up on which lvl 7 you are going to want. Take advantage of the organic bonus and plant what is most useful for you now.