Answer: I think the problem with fertilizer and black eyed susans is that they are one of the perennials that do best in lean soils. As long as you don't overapply the fertilizer, your perennials should be fine. When plants get too much nitrogen they respond by growing lots of lush, green growth at the expense of flowers. So, apply in amounts as recommended on the label (don't overdo!) and feed only once per season. Miracle Gro is fine for hydrangeas.
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