zam,

you might want to ask the Rose Forum. his not really an irrigation question. Aloha

I suspect you misread/ misunderstood the instructions. My experience has been that over fertilized plants act as if they or starving for water by wilting or burning of leaves.

A little fertilizer is good thing; too much is a bad thing.

I prefer to use fertigation, using a much more diluted mix. One tenth of the amount the manufacturers recomends but using it at every watering.

Miracle grow shouldn't be used on anything! Look for natural/orgranic fertilizers and soil amendments.