Question
my coreopsis are in full bloom and look beautiful  However, the leaves look gray-green rather than their usual deep green.  I recently sprayed my plants with a liquid fertilizer.  Could this be a white residue from the liquid fertilizer?

Answer
Dear Helen, Yes the white residue is probably due to the fertilizer.  You can help to remove it by watering the foliage heavily, but you may still see some traces.  To prevent this from happening in future, I would apply the fertilizer to the ground rather than the foliage.  While most of the foliar sprays don't cause this condition in most plants, there are always a few that will react poorly.  The old foliage will eventually grow out and it won't be visible any more.  Happy gardening.  Melissa