BrightView Answers Your Azalea Questions 

Q: Can you tell me how to plant an azalea? 

A: Plant your azalea in early spring or early fall. If your soil is loose, well drained, and has lots of organic matter, planting will be easy. If drainage is poor, you'll need to correct the drainage problem or plant in raised beds. You can work in some well-rotted leaf mold or compost if the soil is short of organic matter. Don’t worry about preparing the soil deeply since azalea roots are shallow and most are found in the top foot of soil. Instead, loosen the soil in a broad area around the planting site. If a soil test reveals that your soil is strongly alkaline, work in enough iron sulfate or ammonium sulfate to drop the pH to 4.5 or 5.5. Your state’s soil testing lab can give you guidance on how much of these materials are needed to acidify your soil. Water the pot thoroughly before planting, and tease the soil away from the roots on the outside of the pot. Don’t worry about injuring the roots; it’s more important to remove a significant amount of the potting soil than it is to keep every root intact. Plant the azalea slightly higher than the surrounding soil since it probably will settle after planting. Finally, water the whole area thoroughly and apply a thin layer of shredded leaves, pine needles, or pine bark to keep the soil cool and moist. Water your newly planted azalea weekly if the weather is dry, at least for the first year. 

Q: How and when should I prune my azaleas? 

A: Prune azaleas just after they have finished flowering. Remove individual branches back to the spot where they join a larger branch. New flower buds for next spring’s bloom are set by midsummer, and any pruning after mid-June could result in diminished flower production next year. Avoid shearing azaleas since it results in a proliferation of unhealthy, twiggy growth. In late summer, check azaleas for wilting or dead branches that may be the result of fungal cankers. These branches should be pruned back to clean, white wood that is not infected while the weather is dry to prevent the spread of diseases. Old azaleas that have grown too large for their space in your garden can be brought down in size by cutting the large branches back severely. New growth will spring from the stubs that are left. 

Q: An old, established azalea died in my garden. What might have caused its death? 

A: There are several possibilities. Voles, also known as meadow mice, may have chewed on the bark and roots near the crown of the plant. Sometimes they chew all the way around the trunk and kill the inner bark, resulting in the death of the whole plant. Keep mulch away from the trunk to discourage voles. The bark also may split when there are wide fluctuations in temperature in the winter. Azaleas may begin to come out of dormancy if late winter weather is warm. If a cold snap follows, bark injury is likely, especially in sunny, exposed sites. Prolonged drought weakens plants and often results in the appearance of fungal cankers on the branches of older azaleas. Look for branches that wilt in hot, dry weather in late summer, and be sure to water azaleas if drought drags on more than a few weeks. Prune out the affected branches to stop the spread of fungal canker diseases.