Care of Evergreen Azalea Plants
Evergreen azaleas (Rhododendron spp.) offer year-round interest with foliage that stays green and spectacular blooms once or twice a year. The bloom time varies with the variety and you can extend the season of interest by interplanting varieties of evergreen azaleas that bloom in late winter, spring and summer. Evergreens that bloom twice a year sometimes have their second flush in fall. Some types undergo fall foliage changes, but the colors are never as stunning as deciduous fall azaleas. Evergreen azaleas are not as cold hardy as deciduous types -- most are limited to U.S. Department of Agriculture plant hardiness zones 5 or 6 through 8 or 9.
Light requirements for evergreen azaleas vary depending on the location. Most do well with morning sun and afternoon shade or in a spot with dappled sunlight all day. Some can tolerate full sun, but the evergreen azaleas that bloom twice a year all prefer a northern exposure. Check the requirements for your chosen variety to make sure it is suited to the location you have in mind. They need a loose, moist but well-drained soil that is rich in acidic organic content such as composted oak leaves or pine needles. A pH of around 5.5 is a must.
Plant evergreen azaleas so that the soil line above the root ball sits slightly above the surrounding soil. Azaleas have many small rootlets near the surface of the soil that need protection from dry conditions. Cover the entire root zone of the plant with a 2- to 4-inch layer of coarse organic mulch to insulate the roots from temperature extremes and conserve moisture. A primary reason that young plants fail is that they were not protected from moisture fluctuations.
Keep the soil evenly moist at all times. If you water the azaleas from above, check the soil to make sure the water is penetrating the thick layer of mulch and reaching the root zone. Fertilize once a year in late winter when the plants break dormancy. Use a fertilizer with twice as much nitrogen as phosphorous or potassium. Fertilizer designed for acid-loving plants is perfect for evergreen azaleas because it helps maintain the soil pH as it feeds the plant.
Encourage bushy growth by clipping off the tips of the branches several times a year. Wait until after the shrub is through blooming for the year before shaping the plant. For evergreen azaleas that bloom twice a year, such as Encore or Indica series hybrids, prune after the second flush of flowers. If you wait until fall, you may lose the next season's blossoms. Remove damaged, diseased and crossed branches any time of year. Prompt removal of problem branches helps prevent issues later on.
- University of California Agriculture and Natural Resources: Evergreen Azaleas
- The Homeowner's Complete Tree & Shrub Handbook; Penelope O'Sullivan
Jackie Carroll has been a freelance writer since 1995. Her home-and-garden and nature articles have appeared in "Birds & Blooms" and "Alamance Today." She holds a Bachelor of Science in medical technology from the University of North Carolina.