How to save a dying rhododendron. Is my rhododendron dead? Will rhododendron leaves grow back? These are not uncommon questions for rhododendron owners.
With their funnel- or tubular-shaped, brightly-colored flowers perching proudly on stems, rhododendrons are perfect if the idea is to have a garden sparkling with colors throughout spring and summer.
Often confused with azaleas, these evergreens are relatively easy to care for and can bloom for several years with slightly-scented pink, lavender, red, yellow, white, and blue flowers.
But rhododendrons can be very fussy if one or more of the conditions for growth are out of sync.
This creates the ideal environment for various diseases and pests to thrive. And if the problems are unattended to asap, they start dying.
This brings us to the focus of this article: how to save a dying rhododendron.
Fortunately, you’d discover that nursing your rhodies back to tip-top shape isn’t hard with the right knowledge at your disposal.
That knowledge, and much more, is what you’d find out in a bit.
How To Save A Dying Rhododendron
Rhododendrons (Rhododendron spp.) are part of a genus of flowering plants comprising over a thousand species.
They are naturally found around the world and are hardy in agricultural zones 4 -8.
They thrive best with their shallow roots in well-drained, acidic soil and are typically happy with moderate watering (about once a week) when the soil feels dry.
Younger rhododendrons require more water though. First-year rhododendrons need watering about a couple of times per week depending on weather conditions.
Other standard growing conditions include shady, but bright areas protected from winds, and a once per year fertilization in fall if necessary.
When all these conditions are provided consistently there is not much to do to keep them healthy except for some light pruning and deadheading to encourage growth.
However, because they are very sensitive, they are readily susceptible to pests and diseases with just a bit of neglect.
The result is a failing rhododendron and ultimately, the plant dies if remedial actions are not taken.
Possible Reasons Your Rhododendrons are Dying
Over-watering & Deep beds – Planting newly purchased rhododendrons in deep beds or holes is one of the leading causes of death.
Many folks make the mistake of burying the whole root ball in a big hole; then proceed to water the soil as usual.
But with their shallow, fibrous roots, the net effect of surrounding the root ball with all that moist soil is the equivalent of too much water.
The shallow roots become literally drowned in excess water. Normal roots functions are impaired while providing an excellent breeding ground for disease-causing fungi leading to diseases such as root rot.
Also, the shallow roots tend to feel suffocated or smothered when buried too deeply.
Even if you somehow get the watering right, they won’t grow but instead, start dying.
If you’ve already made that mistake, the best fix is to uproot your rhodies and plant them in shallow beds of well-draining soil.
Inadequate water – Again this all goes back to the rhododendrons root structure. The root system doesn’t include taproots that can grow downwards to seek moisture deep inside the soil.
The roots are all just under the surface of the soil.
The absence of deep roots means the plants need frequent watering, especially in the first year when it should be done about twice a week.
They are not hardy so neglect in terms of frequent watering can prove fatal.
Over-fertilization – Excessive use of fertilizer is another cause of rhododendron death. This is more prevalent when it is applied directly to the soil at the plant’s base.
The expert recommendation when it comes to fertilization is the product sparingly a few inches from the base of the plant, once a year, at the beginning of the growing season.
Growing the wrong species – Getting and planting a specie not suitable for your hardiness zone exposes the plant to death by frost.
That said, choosing a specie based on the hardiness rating can be a bit hit or miss. This is because plant hardiness rating is basically a general guide to help gardeners in their choices.
So it is quite common for a rhododendron specie with a hardiness rating of 5°F to die when faced with winter temperatures of around 9°F.
In the course of growing rhododendrons, time is your best friend when it comes to selecting the species.
After a few years of losses, via a process of elimination, you’d know the species best suited for your hardiness zone.
Exposure to direct sunlight – Generally, rhododendrons don’t do well when exposed to the full glare of the summer sun for long most especially in warm regions.
In such conditions, they would not survive.
In the warmer southern and mid-western states, gardeners are advised to provide some form of protection from the sun: partially shady areas with filtered light are ideal.
Die-back (Fungal diseases) – Rhododendrons are susceptible to diseases caused by fungi. Collectively, these diseases are known as rhododendron dieback and spring up when the right environment is created for them to thrive.
The right environment includes:
- Soggy soil due to over-watering
- Poor draining soil that retains too much water
- Planting them in deep beds
- Watering late afternoons or evenings
- Not using fungicides in the growing season
The diseases generally manifest at the beginning of the growing season in early spring and late summer.
Whole plants start dying suddenly or branches start dying/falling off.
Symptoms of Dying Rhododendrons
Knowing the signs and symptoms of a dying rhododendron can make all the difference when trying to save the plant. Some of these symptoms include:
Falling stems – This normally occurs in spring or summer. The stem of a seemingly healthy plant can unexpectedly die and fall off.
This is caused by fungal diseases and sometimes, extremely cold temperatures.
Problem with the buds – When buds refuse to open at the expected time, this could be an early warning sign of a fungal disease.
The buds would later turn black and die; a confirmation of the ‘bud blast’ fungal infection.
Leaf spots and discoloration – When the leaves turn yellowish or spots appear on them, this is attributed to a nutrient deficiency, especially magnesium.
Another factor responsible for this in younger plants is excessively high soil pH above 7.
Epsom salts and iron sulfate sprayed on the soil should resolve the magnesium and pH problems respectively.
Pests and fungus attacks in the summer show up as spotted leaves.
Cutting the leaves and their branches is the best way to get ahead of this problem that can be fatal to some species of rhododendrons.
Curling leaves – Curling leaves in summer is the early symptom of underwatering. In the winter, it is a normal occurrence – a winter survival instinct to reduce the rate of water loss via the leaves.
How to Save Your Dying Rhododendrons
How do you fix a rhododendron that is dying? Saving a dying rhododendron is quite easy. If you spot the symptoms early and know the factors responsible, you are already more than halfway down the path to reviving your rhododendrons.
So, let’s get to it.
Cut ailing plant parts
Cutting or pruning all parts of the plant (mostly leaves and branches) that are unhealthy is the first thing to do. Use sharp garden shears or pruners to make clean cuts.
Remember to sterilize the blades with rubbing alcohol before you begin. Also, sterilize the blades before moving on to the next target. This is to prevent the spread of diseases.
Root rot and dieback caused by Phytophthora spp is something you need to keep in mind.
Rhododendrons rarely survive attacks by these fungi and there is no solution to take preventive measures.
One course of action is to test the soil before planting to ensure that the fungi aren’t lying dormant waiting for the right conditions to proliferate.
You could also choose to grow only phytophthora-resistant rhododendron species.
Spray rhododendrons with fungicide
Spray the plants with any captan- or chlorothalonil-based fungicide. You can easily purchase some from a garden center or reputable online store selling gardening items.
Read and follow the instruction carefully so you don’t end up making the situation worse.
If it is possible, consider potting them in high-quality potting soil specifically formulated for plants like rhododendrons and azaleas.
If potting the plant is impossible, try this:
– Dig up and remove as much soil around the plant as possible
– Replace it with fresh, well-draining soil with the right pH levels
– Then mulch the soil heavily with organic material
Moving your rhododendrons to a different location is a viable option if you figured they are getting too much direct midday sun at their current location.
The new location must provide enough afternoon shade.
If relocating is not possible, use some sort of screen to provide shade. Any screen you decide to use must allow light to filter through to the plants.
Keep in mind that, in most cases, direct early morning sunlight won’t harm them.
On the other hand, if the area is too shady, do all you can to provide more light. This might include pruning overhead branches.
- Other measures to save your rhododendrons include:
- Cut back on the use of fertilizers containing too much nitrogen
- Inspect leaves frequently so you can catch some problems early
- If they were planted too deep, uproot and replant them higher up the garden bed
- Test the soil frequently for signs of iron and magnesium deficiency
- If the leaves are drooping, consider spraying them with water in the evening to perk them up.
The beautiful rhododendrons are usually garden plants that are not hard to grow and care for as long as the right conditions are maintained.
But they are so finicky and unforgiving when there is any sign of neglect, quickly breaking out with some tell-tale symptoms to drive home that point.
They’d ultimately die if nothing is done or the wrong solutions are applied due to an incorrect diagnosis of the problem.
However, when accurately diagnosed, saving your rhododendrons is, most often, pretty straightforward.