Sheet Scale question

Hello all,

I am new to this product and I wanted to clarify if there is an easier way to accomplish what I am trying to do.  I am building a landscape plan.  In model view I fave a 100 by 100 foot field which has in it various cad blocks representing tree types.  SO for example I have a circle at 10 feet representing an evergreen tree.  On sheet view, I create a view-port and set the scale to 1/16 = 1 foot and the model shows up great.  I now on the sheet want to create a legend / key depicting what symbol shows what kind of tree.  When I attempt to insert the tree block on the sheet view since it assumes it is 10 ft in diameter it inserts at 5 times the sheet view.  Is there any way to insert the cad block in the same scale as the view-port?  Is there an easier way to draw it keys / legends than drawing it directly in sheet view?  I know I can place it in model view and create a secondary view-port, is this the correct way to achieve.  

Thanks,

Mitchell