Impatiens are not growing -- why?
I planted many impatients in my flower bed which surrounds my old maple tree. The other annuals planted in the bed are doing well, except my impatiens are not growing. They look the same size as they were when I bought them at the garden center (6-8 packs). I planted them about a month ago. I've been watering and feeding the bed. The weather did turn cold last week here in Iowa with highs near 60 for a few days (and evenings in the 50's). Other than that, they are in perfect shade. I did use top soil for the bed; should I mix some sand and compost into the soil? Is the soil too hard for the impatiens? Help!