How To Save A Dying Rhododendron (Quickly & Easily!)

Ryan Womeldorf
by Ryan Womeldorf

With a vibrant pink/purple color, the Rhododendron blooms brightly across the world. These bushes provide magnificent pop of color wherever they spring up. But when they become distressed, it can rob them of their natural beauty. The key is determining the problem.

There are a few main reasons why the Rhododendron would begin to fail and remedies for each. Distress can be caused by bloom failure, chlorosis, windburn, sunburn, and even salt distress. Some remedies can be applied to bring the Rhododendron back to health when the issue has been identified.

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How To Save A Dying Rhododendron

Without proper conditions and care, any plant can suffer. The rhododendron is no different. With too much sun, wind, and salt exposure, the plant can become physically damaged. With improper watering, its growth can be stunted, leaving it wilted and underwhelming.

Distress From Chlorosis

In plants, there can be a reduction in the greenness of the leaves on the plant. This is either anemia brought on by iron deficiency or can be due to a lack of light. If the Rhododendron is looking a little pale and less than green, chlorosis is the likely cause.

  • Check the leaves. Start by first examining the leaves. They will either be yellow with some dark green veins to them or even pale. Check the soil levels and look into how you culture your plants to see where the problem lay.
  • Reset it. Lift the Rhododendron and reset it to higher up in the planting bed. When it is planted too deeply, the roots may not adequately take in the nutrients that it needs to survive and thrive.
  • Cultivation. Rhododendrons have shallow roots. Because of this, if you cultivate the roots, you could be destroying them. These plants require little or even no cultivation because of the shallowness of the roots.
  • Check your watering and fertilization. Keep an eye on your watering and fertilization levels. By doing too much of either, you could be doing more harm than good. Check out a quality gardening manual and look up the recommendations within.
  • Test the soil. Remember, the problem could be a lack of magnesium or iron. Test the soil to see if the levels are adequate. You can then treat those with a specific foliage spray; follow the manufacturer’s directions. If it lacks magnesium, mix two tablespoons of Epsom salt with a gallon of water and spray liberally.

Distress That Causes Bloom Failure

Bloom failure is just as it sounds: it is where the plant fails to bloom correctly—the most common reasons for bloom failure draught, overfertilization, or dense shading. The best solution is to look into your care habits and see where adjustments can be made.

  • Check the area. Take a look at the area where your rhododendrons are planted. When there is too much shade, its blooming can suffer. Try cutting back any plants that may be overhanging or transplant the Rhododendron entirely if you need to.
  • Cut back on fertilizer. Overfertilization is one of the common reasons for the lack of blooming. Try cutting back on any fertilizers that are high in nitrogen. It could cause excess shoot growth instead of blooming which is what you’re after.
  • Deadhead. Try to deadhead the rhododendrons regularly during the spring period. This should help prevent the seed from setting. When the plant produces seeds, it lowers the ability to produce flower buds and that is kind of the point of the Rhododendron.
  • Protect from freeze-thaw cycles. In areas with more extreme climates – both hot and cold – rhododendrons can struggle. This is known as the freeze-thaw cycle. Try making a burlap screen to help mitigate the extreme changes in temperatures. When temperatures are milder, try using an added layer of mulch and try to keep the plant out of the wind.
  • Improper pruning. While pruning is necessary, doing so improperly can prevent flowering. Moreover, it can cause die-back to the bare wood in different varieties of Rhododendron. Look into acquiring a good gardening book that will show you the differences when it comes to pruning.

Combatting Windburn, Sunburn, And Salt Distress

As you are by now noticing, the rhododendrons are pretty particular and are not meant to handle all climates and temperatures. When it is exposed to too much wind, sun, or salt, it can have negative impacts all their own.

  • Sunburn. If you find round, brown patches around the edges or the center of the leaf, that can be a strong indicator of sunburn. To combat sunburn, try watering the Rhododendron for a little longer and doing so more often. Also, make sure to provide a reed screen for additional shade or consider moving it to another spot.
  • Windburn. Excess wind can also damage the Rhododendron. Browning along the edges, particularly on new growth, will likely be due to windburn. Use a reed screen in the interim but consider moving the plant to an area with less exposure. You can even plant a taller shrub to act as a windbreak near your Rhododendron.
  • Salt injury. Exposure to too much salt can indicate that there has been damage done by salt exposure. Start by testing the alkalinity and drainage of the soil. If you don’t know how there is usually a local office that can test it for you. Try lifting the plant and enlarging the hole to about three times the depth and size of the root ball. You can even add soil amendments that help to correct pH and improve the drainage as you need.

Handling Heat, Water Loss, And Winter Distress

Again, rhododendrons do not do well with temperature changes and impacts to exposure or nutrient intake.

You may find that your plant is damaged from extreme heat, a lack of water, or even distress caused by winter temperatures.

  • Frost. Frost can not only distort but also kill the leaves of your Rhododendron. Keep them protected by putting a burlap screen and filling it with straw when the ground has frozen over. If the Rhododendron keeps getting injured, consider a new location come March.
  • Splitting bark. Should you notice splitting bark, take heed. This is a hazardous problem, and there is a chance that the Rhododendron may die back because of it. Paint over any splits with a tree wound sealer or some kind of grafting compound to treat the split.
  • Drooping leaves. Notice drooping leaves? Try spraying a little extra water on them, primarily in the early evening. It should help prop them up once again.
  • Soil drainage. Proper soil drainage is imperative. If you feel like your Rhododendron is suffering from improper drainage, look for water runoff. If it is too fast, try adding in some soil amendments, watering more deeply, and doing so for longer.
  • Mulch the root zone. You could also consider mulching the root zone all the way out to the drip line. This should help maintain that much-needed moisture.

Battling Disease And Pests

Like any other type of plant, the Rhododendron has to be content with pests and disease. When either is allowed to run rampant, it can play havoc on the condition of the plant. Thankfully, you can turn things around and even prevent further damage from happening.

  • Proper pruning. By adequately pruning, you can remove any of the tissue that is dying. The pruning depends and can vary from being as small as a single leave or as large as even a whole branch. When the plant doesn’t have to support that dead or dying tissue, it can work on using that energy for other areas.
  • Use insecticides. You can also try spraying both the stem and leaves of the plant using an insecticide. Should the plant be ill already, an infestation could kill it. Follow the manufacturer’s instructions carefully whenever using an insecticide. Straying can lead to illness and even death in your plant.
  • Move it. If you think that the Rhododendron may be getting too much sunlight, move it. As explained above, too much exposure to wind and sun can be just as dangerous as anything else. Avoid unnecessary exposure to wind and sun where possible.
  • Change the soil. When an area becomes infested with disease or pests, moving it and changing the soil can be the best bet. If you were struggling with water retention, this could be a good idea as well. Remember, you want to create a hospitable environment for the plant to thrive.

Can You Dig Up And Replant A Rhododendron?

Generally speaking, most rhododendrons and even azaleas can be dug and replanted. The key is to use patience and care. Damage can come from you just as much as one of the above factors.

It can even be favorable to transplant your Rhododendron, depending on the climate. You can transplant any time in the most favorable climates, primarily when the plant is not in its soft growth periods. Try to avoid the hottest times of the year, though.

Rhododendrons (and azaleas) have shallow roots that run close to the surface. Most rhododendrons run somewhere within the top 12 inches of the soil that they are planted in. They have a structure of vertical roots that go about the same depth.

Growing Healthy Rhododendrons

When you grow Rhododendrons, there are several things you need to take into consideration. We will take you through these briefly.

Soil Acidity

Rhododendrons require acidic soil with a pH of 5.5 or less. If the acidity is off, the growing circumstances will be less than ideal, and your flowers will have a higher probability of dying.


It’s essential that the soil you use is porous and drains efficiently. You may check your soil drainage by excavating a 12″ x 12″ hole, filling it with water, letting it drain, then refilling it and timing it again. It should drain at a rate of roughly one inch each hour.

If it’s draining too quickly, it’s probably too dry and would benefit from adding organic material to promote moisture retention. Slower drainage is a more significant issue since the roots are sitting in standing water, which puts them at danger for root rot.

If you’re growing rhododendrons in a container, you can enhance drainage by adding up to 20% perlite or pumice. A dusting of elemental sulfur (not aluminum sulfur) around the top of the soil will eventually acidify it once rainwater washes it into the soil mix for rhododendrons that have been transplanted into the ground.

Acidifying The Soil For Rhododendrons

Some soil acidification techniques used to preserve a dying rhododendron can kill it. One of the most dangerous is aluminum sulfate, which is toxic to the roots. Lime is as well.

If your Rhododendron is planted too close to paved pathways or a building, lime may leach into the soil, raising the pH.

The best approach is to plant rhododendrons at least 5-feet away from a building’s foundations. Plant it at least 5-feet away from any other construction that could cause lime to seep and change the soil pH.

If your soil has a pH of more than 7.5, it will be difficult to drop it significantly; in this case, container-growing rhododendrons might be a better option, as it would eliminate a lot of guesswork.

Are Rhododendrons Nutrient Competitors?

Rhododendrons have shallow roots, and other plants and trees can quickly outcompete them. Because they require dappled sunshine, growing them under a tree is common to provide some shade from the hot afternoon sun.

Rhododendrons thrive when at least 4 to 6 feet in between them and other plants with shallow roots. Choose companion plants with a deeper root system that won’t compete for the same nutrients in the dirt around rhododendrons if your design calls for them.

PH Balance

If your soil has a pH of more than 7.5, it will be difficult to drop it significantly; in this case, container-growing rhododendrons might be a better option, as it would eliminate a lot of guesswork.

That could work unless it’s a maple tree with shallow roots and will compete for resources with rhododendrons. Walnut trees are even worse because they release chemicals that can kill rhododendrons, so they will need to be relocated if yours is near one.

Rhododendrons thrive when at least 4 to 6 feet between them and other plants with shallow roots. Choose companion plants with a deeper root system that won’t compete for the same nutrients in the dirt around rhododendrons if your design calls for them.

Our Takeaway

Learning how to preserve a dying rhododendron is only helpful if you can provide it with the necessary conditions. The majority of rhododendron problems occur when one or more of their optimal growing conditions are not satisfied.

Early indicators of root rot, for example, are likely to appear as wilting and yellowing on the leaves due to poor soil drainage. Inadequate air flow caused by grouping two or more rhododendrons or other shallow-rooted plants too close together also encourages fungal diseases.

Check your growing circumstances against the checklist summary above to discover if your plant needs to be relocated or if soil amendments are required. Most problems with rhododendron plants can be repaired with care overtime after the growing circumstances are corrected.

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Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

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