while some states are worse than others if you know they look for it with helicopters in your area, would suggest you keep plants spaced out no more than 2-3 per spot and while surrounding vegetation helps it will do little to prevent it from being spotted from the air if a helicopter happens to fly over it at the right angle.
plants need alot of sun so unfortuanatly you cant really plant it in the shade of a tree.
most growers will not plant on their own land and while many plants are commonly destroyed without any charges ever being filed it isnt wise for you to grow it in your back yard were cultivation could easily be linked to you.
in cases were the patch may be larger leo does have the ability to set up cameras in an attempt of finding out who the cultivater is and to use the film as evidence against you in court have known a few who have been caught this way and really wouldnt consider non of them to be large patches being about 15 to 20 large female plants.