By: Jackie Carroll
Azalea bushes without leaves can cause anxiety as you wonder what to do. You’ll learn to determine the cause of leafless azaleas and how to help the shrubs recover in this article.
No Leaves on My Azaleas
Before deciding that there is something wrong with your azalea, give the leaf buds plenty of time to open. Deciduous azaleas – those that lose their leaves in the fall and regrow them in spring – usually have blooming flowers before they have leaves. Wait a while before you worry that this azalea is not leafing out.
Some azaleas are evergreen in warm climates and deciduous in cold climates. Most azaleas that appear to be evergreen actually have two sets of leaves. The first set leafs out in spring and drops off in the fall. You don’t notice the drop because another set of leaves appear in late summer and drop off in spring. During unusually harsh or long winters, azaleas that have held their leaves year round in the past may behave like deciduous azaleas.
My Azalea Shrubs Do Not Have Leaves
Cold weather injury often causes azaleas to leaf out significantly later than usual. In order for leaf buds to open, the plant has to experience a period of cold weather followed by a period of warm weather. If cold weather lasts longer than usual, the buds are late to open. In addition, severely cold weather or heavy snow accumulation on the branches can damage the buds. To determine whether the buds have cold weather injury, cut them open. A damaged bud is brown on the inside and green on the outside.
Scrape off a little of the bark and check the color of the wood. Green wood means the branch is healthy and brown wood indicates that it is dead. Dead wood should be trimmed off. Cut the twigs and branches back to a point just beyond a side branch to encourage healthy regrowth.
If your azalea won’t grow leaves, you should also consider the possibility of diseases. Leaf rust is a fungal disease that causes yellow flecking on top of the leaves and rust-colored pustules on the undersides. When the disease is severe enough, the leaves fall off. It’s best to pick off all of the leaves as soon as the symptoms appear to prevent the spread of the disease.
Phytophthora root rot is a disease that lives in the soil, preventing azalea leaf growth and causing older leaves to drop off. There is no cure and the shrub eventually dies. You can confirm the diagnosis by checking the roots. They turn reddish-brown and die off when infected. You may only find roots in the top few inches of soil.
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It is a shame when azaleas fail to flower well because these bushes can be spectacular when in bloom. A type that many gardeners especially like is the Stewartstonian azalea. Be prepared to do a little research, because there are a number of potential problems to consider when trying to account for why azaleas fail to bloom you will learn about them below.
Although azaleas symbolize temperance in the Victorian language of flowers, their toxicity lent them to a superstition: If given in a black vase, azaleas represent a death threat.
If you've already tested and adjusted your soil since azaleas are acid-loving plants, then here are six other factors to check:
Even if you have had the plants for a long time, it never hurts to double-check that they are properly located. Nearby trees grow over time, increasing shade levels. Or, conversely, if you have lost any nearby trees or had a tree removed or limbed up, your azaleas will be getting more sun than they used to.
Some types of azaleas like a bit of shade, as well as some protection from winds. But when located in excessive shade, azaleas may produce a lot of greenery but fewer blooms.
There is a delicate balance to maintain here. Azaleas can't be allowed to dry out. But they do not like "wet feet" either. Mulching can help with water retention and protecting the roots from the heat (but your mulch layer should not be any deeper than two to three inches).
While the Holly-tone is a good choice, stay away from fertilizers high in nitrogen, which will spur foliage growth but interfere with blooming.
Did you change your pruning habits last year? For azaleas, the current year's blooms stem from flower buds developed during the prior summer. If you pruned later than normal last year, you may have inadvertently removed the flower buds.
This possible cause is related to the previous one. Except, here, it is the pest that does the "pruning," not the gardener. In some areas, the pest most likely to be the culprit is deer. Since azaleas are not deer-resistant shrubs, it is entirely possible that Bambi came onto your property for a midnight snack one night and ate the flower buds right off your poor plant. What is the solution to this problem? If you live in deer country, you may want to erect deer fencing.
Try to remember what the weather has been like over the past year. That may be a lot to ask (some of us have trouble recalling yesterday's weather sometimes), but it could hold the key to your problem.
Azalea: Spectacular Shrub of the South
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What, then, is the difference between an Azalea and a Rhododendron? Azalea blooms are most often funnel-shaped and have five stamens. Rhododendron flowers are most often bell-shaped with ten or more stamens. Rhododendrons thrive best in the Upper or Mid-South. If growing requirements are met, Azaleas will do well throughout the entire South and usually are more adaptable to growing conditions than Rhododendrons are. Also, Azaleas generally have much smaller leaves.
Azaleas may be evergreen or deciduous. Evergreen varieties usually have thicker growth. You can tip-pinch them fairly frequently to maintain shape. Do this after flowering ends, up until about the middle of June. Prune deciduous azaleas while they are dormant and leafless. Leaves are somewhat evenly spaced along the branches of both types and have a bud at the base of each leaf. The new growth will sprout from almost any spot a pruning cut is made.
Azaleas like rich, well-drained, acid soil. They should not be allowed to become too dry or too soggy. Planting in heavy clay soil often causes root rot and the collapse of the plant. Planting in alkaline soil will eventually cause chlorosis (yellowing leaves with darker green veins). When Azaleas are planted, the root ball should be slightly above the level of the soil. They have shallow root systems and do not like to have other plants growing at their base.
These plants will absorb water through the foliage, so wet both the leaves and the root zone when you water. In order to help prevent fungal diseases, it is best to water in the morning so that the leaves can dry by afternoon. Drip irrigation does not usually provide enough water to satisfy an Azalea.
Immediately after the blooms fade is the best time to apply mulch and to fertilize with an acid-forming fertilizer, such as a commercial Azalea/Camellia food or cottonseed meal. It is best not to mulch in the fall because the mulch will hold heat in the soil and delay dormancy. Fertilizing before the plant blooms will produce heavy leaf growth with few blooms.
There are many beautiful varieties of Azaleas. The sun and heat tolerance of the different varieties will vary. Check out the ATP database for the names, photos, and proper care of the different varieties. https://garden.org/plants/sear.
One of the main questions at this time of the year is – “Why are so many of the leaves on my azalea plants turning yellow?” This year, it appears many azalea plants have more yellow leaves than green leaves! Usually we see a few older leaves yellowing with the younger leaves remaining green. However, in some cases, many leaves are turning yellow. Why is this condition so bad this year?
Remember, a plant losing some of its leaves is a normal process. The older leaves die and younger ones replace them. You would only be concerned if most of the leaves are yellow.
The traditional reply is that the plants have run out of fertilizer – particularly nitrogen. Nitrogen-deficient azaleas will shed older leaves. This is certainly a possible cause. And why did this happen? Azaleas may have missed their last fertilization in July or August or just never took up the fertilizer available.
Don’t worry about these plants. They should bloom normally in the spring. Fertilize them after the danger of frost is past – about April 1. Do not fertilize them now. This may cause the plant to start growing again. And this new growth, in turn, will be cold-tender and may be burned back by our winter weather.
Our unusual weather may be causing a problem with azaleas. Azaleas are a Southern favorite, but they are somewhat temperamental. Their fine fibrous roots like well-drained but moist soils. This year’s summer drought, followed by a wet autumn, may have damaged these roots. This is especially a problem in areas not suited for growing azaleas. Azaleas do not like wet or very dry soils or full sun locations.
There is not much we can do about this now. Fertilizing now will not fix this problem, and in fact, could further complicate the situation. Proper planting and maintenance will help prevent this problem in the future.
Plant azaleas in well-drained soils in partially shaded locations. The shade provided by planting them next to a building is not always enough shade. If they must be planted in the sun, they prefer the morning sun. Plant azaleas in slightly raised beds, if possible. Plant them no deeper than they originally grew.
The roots may be pot-bound when you buy them. This is when the roots are tightly matted together. Pot-bound roots form a tough ball that the roots may never grow out of. Cut the root ball or break the roots down four sides of the root ball if the plant is pot bound. Spread the roots out as you add soil.
Also, plant azaleas in beds, if possible, and not individual holes dug in the ground. Till the area well. You do not need to add compost to the soil. Put a three-inch mulch over the entire bed after planting. Water the soil well to settle the roots. Plant in fall and winter for best results.
Proper planting and watering are critical steps in assuring success in growing azaleas. Azaleas and other shrubs must be watered for best results. This is especially true during the first year. Water the soil so as it keeps it moist but not wet for the first six months. After that, water when soil dries out, wetting the soil to a depth of twelve inches. Water three-quarter to one inch a week during drought conditions. After plants are established, do not water every day or every other day! Frequent watering can kill plants.
Two other leaf problems with azaleas are: 1)iron deficiency and 2) lace bugs. An iron deficient azalea will have yellow or white younger leaves. The leaf will be yellow with green veins. Use a soil applied iron fertilizer at the labeled rate. If the iron deficiency returns quickly or repeatedly, the azalea may have root injury or the soil pH may be too high.
Lace bugs make the leaves look speckled or silvery. The underside of the leaves will be brown speckled. Wait until March and treat the plants with Orthene or other recommended insecticides. Read and follow all label directions.
Enter the New Year with healthy azaleas. Azaleas may look sad and unsightly now, but they can return to healthy plants with proper care.
Center Publication Number: 230
Look at this too from our friends in Cobb County: Azalea Leaves Turning Yellow, Dropping?
Water requirements may vary between azalea species, as well as the climate and the amount of light that your shrub is exposed to. If it is placed in a colder region or shaded area, it is typically best to water the shrub less, only as often as twice or thrice a month.
In warmer regions, you may need to water it around once or twice a week. Be sure to check the soil moisture before watering as these plants generally cannot tolerate soil soaked with too much water due to its shallow roots, or it will drown.
It is crucial to provide good drainage to the soil to avoid these conditions. It can also be a good rule of thumb to water the plants as soon as the upper three inches of the soil starts drying out.
Appreciation is expressed to Dr. Frank Bryan, Albert Penland and James Thornton, members of the Oconee Chapter of the Azalea Society of America, for their assistance with this publication as well as a corresponding PowerPoint presentation.
Acknowledgment is also made to Dr. Frank Bryan, Richard Clapp, Allison Fuqua and James Thornton for providing many of the photos within the publication. Last, but certainly not least, sincere appreciation is expressed to Sharlys Crissafulli, Program Assistant in the Department of Horticulture, for her tireless efforts in editing and formatting this publication.
Status and Revision History
Published with Major Revisions on Oct 22, 2007
Published with Minor Revisions on Nov 30, 2007
Published on Sep 10, 2010
Published with Full Review on Nov 10, 2013
Published with Full Review on Aug 01, 2016