Fall is such a good time to plant perennials and to take advantage of sales when plants are quite inexpensive. However, no plant is a bargain if we let it die because of neglect.
I sometimes stick a plant in the ground and then forget about watering it, and so it understandably fails to become established. When you bring plants home from the garden center, put them in a shady and protected spot until you move them into the garden. Keep the pots well watered as small pots particularly dry out quickly.
Bare root plants that arrive in the mail in packing material should be kept moist; if the material dries out, it can be deadly for the plant. Before planting soak bare roots for an hour in warm water.
Cool, cloudy and rainy days are best for both planting and transplanting.