Your leaf highlights in the sun are going to give you some points of white light regardless, if you are unsure of whether to increase or decrease development, always go with the lesser, it is easier to make contrast then to dilute it, id go with a wide range developer, not something like POTA but maybe something with stand development capabilities, rodinal? with slightly increased time. what the filter does is passess its own colors and blocks others that it is rated to , at the extent it is rated too, i think your filter may be comprable to the #11 wratten yellow/green, green foliage is not highly saturated green and will not increase in negative density with use of even a #61 deep green filter, the yellows probably didnt increase much, you should only worry if your using something like a #15 with a yellow flower, in which case no factor would be given as it readily passess the yellow and does not signifigantly lower other values (unless in a highly saturated landscape) the reason for giving a filter factor is to give more exposure to those colors which are blocked by the filter, which in turn increases hte passed exposure, therefore filter on lens exposure often deals with over exposure, but i think for your case you would be fine with the type of development i suggested