Posted by Brent Wilson on 9/10/2016 to FAQ (Frequently Asked Questions)
One morning you leave for work or play and your azalea looks happy and healthy and later that day you come home to find that the leaves are wilting. No need to get too worried just yet. Sometimes wilting leaves are a sign of a serious underlying problem, other times it's a natural occurrence that does NOT threaten the long term health of the plant.
There are several possible causes for wilting leaves on azaleas. I've listed them here so you can determine what might causing them to wilt an employ a remedy if necessary.
Damaged or Broken Branches
If the trunk or a branch or stem on your azalea has been damaged or broken water won’t be taken up into the twigs and leaves. Look carefully from the base of the main trunk to the top of the plant for breakages or damage to bark. If you find a damaged area or breakage the branch will need to be removed as soon as possible using bypass hand pruners. Make your pruning cut at a point an inch or two below the point of damage. Good news is, azaleas respond very well to pruning and new branches will form to fill the void created when the damaged branch was removed.
Perhaps the most common cause for wilting leaves on azaleas and many other types of plants has to do with a soil moisture issue, when the soil around the roots of the plant has become too dry. Azaleas, especially recently planted or young plants, require a consistently damp to moist but well-drained soil in order to establish a root system. When they don't get enough water the leaves will wilt. If you’re relying on an automatic sprinkler system and assuming that it’s delivering enough water to all the plants because the soil looks damp on the top, this might be the problem. Sometimes automatic sprinkler systems soak one area but only dampen the surface near the other plants. The same is true if you're splashing just a little water around plants every day instead of deep soaking less frequently.
On the other hand, constantly soggy or wet soil can be a killer of azaleas, causing the roots to rot. Prolonged exposure to excess water causes waterlogging, which interferes with aeration of the roots, leading to low oxygenation and decay, what we call root rot. Root rot is primarily caused by overwatering or poor drainage. Rotting roots don’t allow the foliage to get the moisture they need so the plant wilts even when the plant is constantly wet. When the roots begin to rot leaves also start to turn brown or black at the ends and gradually spreading to the base of leaf.
The only way to know for sure if there's a soil moisture problem is to test the soil to see if it's too dry or too wet. After plants have been irrigated, dig down near each plant and see if the soil is truly moist to at least a depth of 8 inches. If the soil is dry, make sure to provide more water when watering. Then, only water again when the top inch or two of the soil has become dry. If the soil is soggy wet, hold off on the watering until it has become somewhat dry, then deep soak again. If the soil tends to stay soggy for a prolonged period of several days or more, I would suggest testing the soil drainage. If the test results indicate poor draining soil, steps must be taken to either improve drainage in the planting area or lift and replant the azaleas in a raised mound.
Heat or Sun Stress
Sometimes you can provide just the right right amount of water but even when the soil is moist the leaves on your azalea wilt during the hottest hours of the day in summer. This is especially true with young or recently planted azaleas growing in a location that receives afternoon sun because they haven't developed enough of a root system to supply water to the foliage as rapidly as it is lost by transpiration from the leaves. This temporary daytime wilting is usually not a serious problem. However, if the leaves of your azalea remain wilted through the night and in the morning hours, when the temperatures are cooler, this could be an indicator there's a soil moisture problem or the plant is suffering acute heat stress. First test soil moisture as advised above. If the soil moisture is okay try to find a way to provide some shade to plants until the heat wave has ended or relocate plants to a location that receives afternoon shade or filtered sun. That said, if your azaleas have established roots in the native soil you must wait until the plants have gone dormant for winter to relocate and transplant them. Plants that have yet to grow roots can be transplanted any time of year.
Tip: Though many types of Azaleas such as Encore Azaleas and the Southern Indica Azaleas will tolerate full sun, I think that all azaleas growing in landscapes of the deep South and other hot climates will appreciate some shade or filtered sun during the mid-afternoon hours in summer.
As with almost every other type of plant, azaleas will sometimes attract insects. Most insects don't cause problems however an infestation of leaf sucking insects, such as lacebugs, which are probably the most common pest on azaleas, can cause leaves to discolor and wilt. Check the undersides of the leaves on your azalea to see if there are any insects hanging out. Some leaf sucking insects are very small, or camouflage themselves well, so you might want to use a magnifying glass when searching for them. If you find lace bugs or other insects on the leaves of your azalea, follow the link below to find more details and methods of control and prevention.
As with all other plants and living things, azaleas are susceptible to fungal disease.
Powdery Mildew - Azaleas, especially those growing in dense shade and that don't receive morning sun are susceptible to powdery mildew, a fungal infection that can make the leaves look as if they've been sprinkled with baby powder. If the powdery mildew is not treated it can cause leaves to wilt. If you would rather not relocate the azaleas to a location that receives some morning sun, neem oil or products made with sulfur or potassium bicarbonate can be used to effectively control powdery mildew.
Leaf Spots - Leaf spots caused by fungal infections are normally brown or reddish brown and may have tiny black spots in the centers. The black spots are fruiting bodies. Fungal leaf spots are irregular and may spread and merge. Severe infections can cause leaves to wilt and eventually kill the leaves, but most healthy azaleas can withstand this type of infection with little obvious damage. Prune away infected areas and dispose of the material and any plant debris found at the base of the plant. To prevent leaf spot, if possible, water the azaleas at ground level rather than overhead sprinkling to prevent spores from spreading. Fungicides can be used for control and are most effective applied at the end of the blooming period, with repeated applications every two weeks.
Twig Blight - The first indication a gardener may have that an azalea is suffering from twig blight is the death of the plant's leaves. If the foliage on a branch wilts, dies and falls from the plant, check the woody tissue beneath the branch's bark for reddish-brown discoloration. Twig blight, caused by several types of Phomopsis fungi, may spread to other branches, causing leaves to wilt and eventual defoliation of the azalea, usually on one side of the plant. Prune away diseased branches at least two inches beyond the limits of the discoloration under the bark. Sterilize the blades of the pruning tools in between cuts and in between plants to avoid inadvertently spreading the infection. Keep the azalea as healthy as possible to help it recover.
Leaf Rust - Caused by Pucciniastrum vaccinii, leaf rust usually occurs in midsummer, with spots that start out small and yellow on the leaf surface while spore-filled, rust-colored pustules develop on the underside. Spores travel through the air to spread infection throughout the plant as well as to nearby azaleas. Spores may also reach the azaleas from any hemlock trees growing in the vicinity. Clear away fallen leaves and other plant debris to prevent the infection from overwintering and attacking the azalea next year. Fungicides are generally not required.
Hope this information was helpful and that you were able to use it to determine why the leaves were wilting on your azaleas. If you need more details or have any other questions don;t hesistate to contact us.
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