Azaleas (Rhododendron spp.) are usually sold with their roots in soil, either in a container or balled and burlapped, but they are sometimes sold without soil on their roots, or bare root. They are hardy in U.S. Department of Agriculture plant hardiness zones 3 to 9 in general, although this varies depending on the species and cultivar.
Best Time to Plant
Plant deciduous and evergreen azaleas while they are dormant. In warm, mild-winter climates of USDA zones 8 and 9, B&B and container-grown azaleas should be planted between November and February. Plant them in the fall immediately after the deciduous trees drop their leaves or in early spring before they begin to put on new leaves in the cooler USDA zones 3 to 7. In very cold USDA zone 3 and 4 climates, fall planting should be done between mid-August and mid-September.
Acceptable Planting Times
Azaleas in Soil
Plant B&B and container-grown azaleas as soon as possible if they are purchased later in the spring, in the summer or in early fall. Moisten the soil around their roots if it begins to dry before they can be planted. While these are not the best times to plant azaleas, they can survive as long as they are planted properly and watered often enough to keep the soil moist. In USDA zones 8 and 9, they may have to be watered every couple days or even every day after they are planted if the soil is sandy and drains quickly.
Plant bare-root azaleas in late winter or early spring as soon as they arrive. They must be planted after the ground thaws but before deciduous trees in the area begin to put on leaves. Mail-order companies usually ask for the planting zone and ship azaleas when they should be planted in the area.
If they cannot be planted on the day they arrive, check the roots to make sure they have not dried out. Moisten the packing material around the roots if it has begun to dry; seal them in a clear, plastic bag; and put them in the refrigerator until they can be planted. Do not store them for more than a few days.
Water evergreen azaleas like 'Gerard's Rose' (Rhododendron 'Gerard's Rose') right up until the ground freezes after planting in the fall. 'Gerard's Rose' grows to a height and width of 2 to 2 ½ feet, blooms in pink and is hardy in USDA zones 5 to 8.
Evergreen azaleas are especially prone to winter desiccation and scorch from cold temperatures, wind and too much direct sunlight. Give them plenty of water until the ground freezes and plant them in a partially shady, protected area to help prevent winter damage.
Deciduous azaleas like 'Golden Lights' (Rhododendron 'Golden Lights') are not prone to winter damage because they lose their leaves. 'Golden Lights' grows to a height and width of 3 to 6 feet, blooms in yellow and is hardy in USDA zones 3 to 7.
Fall-planted deciduous azaleas should still be watered right up until the ground freezes, but they do not need as much water after they lose their leaves.