Fall is the best time to plant almost all perennial plants.

In the fall, the soil is still warm, so roots will continue to grow. Plants planted in early spring, meanwhile, get off to a slower start because the soil has not yet warmed to optimum temperatures for root growth. Fall-planted plants begin root growth more quickly the next spring, and stem growth follows sooner.

Additionally, fall plantings do not have to contend with the stress of summer heat and potential drought. Cooler daytime temperatures are gentle on plants as they get established, and the slant of the sun is less harsh. Pests and diseases are less prevalent in the fall, as this year’s bugs die or prepare to hibernate, and the humidity that promotes many diseases fades away.

The best time to do your fall planting is about four to six weeks before the expected first hard frost. (You can find out this date in your area from your local extension agency.) Water regularly until new plants are established, paying particular attention to evergreens. After the ground freezes, mulch around your new additions.

If you can, watering in the morning is generally best or at least early enough in the evening so that moisture on the foliage will evaporate.