How to plow under anything
You can plow under trees, flowers, buildings and decorations so there is no need to put anything in storage and mess about bringing them back to your farm when it is done. Leave everything on your farm as is. You may have to move things that don’t hide i.e. some of the trees for decoration don’t hide such as palm tree with lights. These will be the only thing that you have to move into storage for now.
Go to your farm. Now go to the top right of your screen and see the six small icons in squares. You need to go to the one that looks like a spanner ( 4th one along). Turn of trees, flowers, buildings and decorations by unchecking each box and then click the green tick. Refresh your farm by clicking on play (top left, next to send gifts).
Go to the farm you were working on if you did not make it default before. Now just plow one field/one plot anywhere on your farm that you know you can normally plow. Now with the bulldozer delete that one field/one plot. Now you can plow anywhere you like, where trees, buildings, flowers and decorations would normally be showing.
When you have finished plowing go to the spanner and turn back on trees, flowers, buildings and decorations by putting a check in each box.
When it reloads you will see plowing under any obstructions. Hey Presto.
Now you can seed, harvest and plow to your hearts content. The plowed fields will remain there until you decide to delete them.
If you are using the overlapping method and want to plow under things you must make sure that before you start overlapping each farm put one field/one plot and then delete on each open tab otherwise you won’t be able to place your field and will get the red highlight when trying to place near or under hidden things.