Desert Roses Leaves Turning Yellow: Reasons & Solutions

Yellow desert roses leaves may mean you could be over-watering your plants. There's an easy way to recognize this. Let's see some possible reasons why.

• Over-watering
• Under-watering
• Natural yellowing
• Sun stress

Reason #1: Over-Watering

Firstly, you can have a look at the tip of the leaf:

The yellowing starts from the tip of the leaf and slowly spreads inwards. Initially, you'll see the leaves getting kind of darker–like it's slowly bruising in. Then some days after that, it will turn more yellow/brown and dry.

In this case, you can save it by reducing the water amount immediately. Or try sucking out the moisture using some napkin, Q-tip or sand. If your plants are bigger, you could get new soil for them. Be careful with shocks during the transplanting process, which could lead to a shrunk caudex like one of our readers has experienced here in this post: How to save soft caudex adenium.

However going back to our discussion on over-watering, the reason why many people (like us) overwater the plants may be because the experience of spraying or watering our plants, I guess, feels good & could sometimes be addicting. It's easy to go overboard. We try to water less by making the spraying bottle slightly harder to press or put in less water.

In another case, if the yellowing starts from the inside (or put another way the belly) of the leaves, as you can see in the picture below, it may reflect something different:

Reason #2: Under-Watering

If the yellowing starts from the inside of the leaves & spreading out to the tips, this may suggest lack of sunlight or under-watering. To make sure, check the soil condition & look at the adenium overall body. If the soil is dry & the adenium body looks wrinkled with non-glossy leaves, then the plant may be thirsty.

Sometimes when people want the adenium to go dormant in the winter, they leave it inside the house & stop watering. This lack of sunlight triggers the yellowing & dropping of leaves.

Under-watered adenium is easier to save than the over-watered one. Give your babies some sprinkle of water. Then move it out to some area with more sun during the day gradually but not too rapidly. They will gradually recover.

From what we've explored so far, the basic idea of yellowing may be simplified as:

If we look at the leaf as our little water measurer, it may be telling us what's going on inside the plant. If the yellowing starts from the tip in, it may be too much water. If the yellowing is from the inside out, this may mean too little water.

Please also note that these are strictly observational notes from experience and we are by no means experts on this. Your experiences may differ a bit.

From what we've seen, the good news is that even after all or most of the leaves have turned yellow the plant will live on. It will not die so easily. It will shoot out green leaves when the conditions afterwards are sufficient.

And these yellow dry leaves are tough survivors on adenium seedlings. Unless we pluck them off by hand, they will remain hanging on the stem for quite a long time. They look like thin dried brown packaging paper.

As an analogy, the yellowing of adenium leaves may be like the shedding skin of a snake. It only makes the plant stronger as it is adapting to the environment.

This is one of the amazing things about adenium. They are very forgiving. As new growers or beginners, we can make mistakes, learn something and try again. It's okay.

The third possible reason could be:

Reason #3: Natural Yellowing

If you try touching the yellow leaves and they fall off immediately, this means it's natural yellowing. The leaves are in its natural cycle to turn yellow after flowering & everything is okay. You don't have to worry too much in this case.

Another sign to tell you that it's natural yellowing is when you touch the caudex (the base) of the adenium, it will be full and hard–not wrinkled and soft.

Some growers notice that natural yellowing happens often during the rainy season–even with very well-cared-for plants. Some variety shows this reddish tint on the leaves before yellowing and dropping:

Yellowing goes from the lower leaves all the way up to the top leaves of the branch. As the lower leaves are older leaves. This is the adenium changing leaves in its normal cycle and you don't have to worry too much about this. Trust the process and it's all good. You can use the fallen yellow leaves as mulch or fertilizer for the plant.

Another kind of natural yellowing is the plant:

Going Into Dormancy

As the adenium go into different degrees of dormancy in autumn, their leaves will turn yellow and fall off. This is visible in varieties like Adenium Boehmianum and Adenium Swazicum with a complete fall-off of the leaves.

As the autumn equinox is approaching, the plant may be letting go of older leaves in response to shortening (more cloudy, darker) September/October days (less light = fewer leaves - leaves drop off). So if this is the case, it is a natural cycle. New, green leaves will grow out again when spring comes.

Reason #4: Sun Stress

When it's summer or there are heat waves passing by, the yellowing of adenium leaves may be they are putting on sunscreen or sunglasses to protect themselves. The yellowing helps reduce the excess amount of sunlight the plants take in, and reduce photosynthesis. As the hot season is over, the leaves will gradually turn green again.

Also, in summer, keep the plants facing one same direction. If rotated, the side that gets more shade may not get adapted yet and intense sun can burn it severely. Especially with the approaching autumn sun when it's low in the sky but still very strong.

After winter storage, when the plant first meets its first sunlight again, its leaves may scorch (get sunburned). This is not a severe issue however because new sun-adapted leaves will begin to grow out soon.

Also Check the Roots

If, however, you press down on the leaves a few times but they don't fall off instantly, then check the roots. It may be root fungal diseases or too many string roots. The good bits may not get carried up to the leaves, causing yellowing.

You can see some white fuzz start colonizing on the adenium root above. From one grower's experience, this is one early sign of the root or caudex about to rot.

To save it, you can dig the plants up. Cut off some mushy roots. Then dry it under the sun. Remember to apply some sealant (garden lime or cinnamon ground) to help the open wound. Let them rest for 7-14 days. Replant your desert roses in new soil for recovery.

If you want a closer look to deal with root rot, check out this post below:

Pests & Fungi May Cause Yellow Leaves

If the adenium has been infected with pests or fungi, you may notice some tiny dots on and under the leaf surface. Compared to natural yellowing, the yellowing caused by pests has a brighter yellow all around the leaf.

While natural yellow leaves fall almost instantly on a gentle touch, the infected yellow leaves may not. Even if you push down on the leaves a couple times, they will remain quite attached to the branch.

Another way to tell if the adenium is infected by pests or fungi is to look at the caudex. In this case, your caudex may get shrunk a bit smaller. And when you touch it, you may feel that it's not hard any more but quite soft.

Here are some 'partners in crime' faces:

1. Red Spider Mites

Red spider mites are tiny red insects that can suck the nutrients out of the adenium leaves, causing them to yellow. They appear again & again each year.

You can catch these guys running up & down on the underside of the leaf like here:

Along the spine of the leaves are their white eggs. These become baby mites in about 4 days. A very fast and efficient production.

To tell whether your adenium is naturally yellowing or there might be some mites around, look for the direction of the yellowing.

If it starts from the lower leaves up, then it's normal. If it starts from the young leaves on the top, then it might be the mites. Because they love chewing on these fresh young adenium leaves on top. The lower leaves are old yellow leaves.

If the condition of the leaves is not too bad, you can use a garden hose to hose them off. Or use some gloves to rub them off.

If condition is quite bad, then we might need to use some sprays. Be careful with chemical sprayers. The products that promise to kill the eggs or the babies too are highly toxic.

To rid them off safely, you could try this recipe:

• 3 parts boiling water
• 2 parts room temperature water
• 3 cc (3 ml) dish soap
• Optional: mint essential oil, neem oil, horticultural oils, red wood fiber

Spray this solution on the leaves late in the afternoon when the weather is cool. You can also try soaking chopped onion in water. Then, extract that juice for spraying. The idea is to make the pests 'cry' or at least 'tear up'. Termites hate red wood fiber. It may be the redwood smell that keeps them away effectively.

Cold Pressed Neem Oil
100% pure oil (no chemical additives)
Does not burn plants
Effective

When the mama mites sense the smell of the spray (the dead zone), they will think twice before landing on the leaves & laying eggs there. The soap & oils may dissolve their soft body or protective coat. It's the smell + the dissolving that work together to keep insects away. Neem oil also messes with their reproduction system a bit.

If they have been scared by the spray once, they have the 'memory' not to find that spot to reproduce again. Hopefully they have a good memory. It's better to prevent this than treating it afterwards. Because you know they may come again seasonally.

2. Mealybug

Mealybug usually attacks the caudex & roots of adenium. It can make your adenium weak & lessen the overall ability to process water and nutrients. This also causes the yellowing & dropping of adenium leaves.

Here you can see the white little creature with 2 antennas:

In this case, the adenium leaves may turn duller, droopy, not glossy & more yellow. The caudex may get shrunk smaller.

To save your plants, dig them up. Wash the whole body thoroughly with water. If it's really bad, use some purple insecticide like Starkle G to spray around the roots. Leave it in shade for 7-10 days. Then, replant your plant into new soil. Be careful when using chemical insecticide because most of them to a degree are toxic.

If it's not too severe, you can also use some onion juice or the spray recipe we've shared above with the oils & soap. Spray around the leaves or pour some around the roots, where these little guys usually start their lives.

Oh and to make onion juice. You just need to chop up some onion, then soak them in water. After a few days, use that extract to spray around the plants. Onion, garlic & mustard have some sulfur in them (noticeable by their characteristic strong smell). It's effective for "shooing" these bugs away while not killing them.

3. Fungi

People usually call this leaf spot. Or Anthracnose disease, caused by this long-named fungi Colletotrichum gloeosporioides penz. It looks a bit like this:

This usually happens at the beginning of the rainy season, when the humidity is high. There's excess nitrogen around the tree & that attracts the fungi. They can spread to other leaves & flower buds on the tree, often leaving black spots on the flowers as well.

Some folks just let the leaves fall. The next season, new leaves will grow out normally even though they can be quite wrinkled. Others use fungicide to kill the the fungi.

You could also move your plants somewhere more dry & with sunlight. Bottom water the plants sparingly to avoid water contact on the leaves. Cut off some infected branches to avoid the fungi spreading into the tree.

>> Link Blog post: What is Causing Leaf Spot and Drop On My Desert Roses?

Also, watch out for these little guys:

4. Aphids (Yellow Bugs)

Yellow bugs (aphids or sometimes called sesame bugs) love partying around the flower buds. But they come & go fast. You may see them tonight & tomorrow they're gone.

They live symbiotically with ants. They give ants the sweet honeydew juice. Ants lead them to the sweetest spots on the plant & protect them from lacewings/ladybugs. Dish soap spray & onion should get rid of the aphids. Horticultural oils can also work.

If you want to try something different, try beer + water. Spray it all over the plant and after one day, the bugs will be gone. You can also use the mix as a prevention.

For a strong measure, growers use ant/insect sprayer. Some worry that this strong mixture may burn the leaves. But from the results, it has not been so. After about 6 hours, the bugs will be dead. You'll see them stop moving around the leaves & flowers.

The appearance of these little creatures may invite some other badass guys to the garden, like this one:

A guy on Reddit told us that this is the yellow-spotted stink bug (Erthesina Fullo). We wonder if their food is the mealybugs or spider mites. This specie can be really invasive.

Around your garden, have you at any point in time spotted:

5. Green Worms

Green worms will usually eat your adenium leaves (it is their favorite 5-star Michelin restaurant dish). Green worms are the offspring of the butterflies. When the worms eat the young shoots or flower buds, they'll make the shoots and buds become 'stagnant' or 'halted'. Which may be one reason why the desert roses are not blooming.

If you catch the worm egg or the worm poop on your adenium leaves, you have an idea now of who has been around. When the worm poop has a slightly red color to it, it may mean the worms have been enjoying your red adenium flowers - yum yum. If you see the poop is slightly more green or blackish, maybe they've been chewing the leaves.

Young worm eggs have a green-yellowish color. The darker blackish eggs mean they are older and about to hatch.

Once hatched, these guys act very fast and efficiently. Within one night, one or two green worms could chew off a small adenium plant–making it go somewhat entirely 'bald'.

Adenium leaves are the favorite food of green worms. So watch out for these guys if you'd like to keep your adenium leaves green and healthy.

Adenium Recovering: For Glossy Green Leaves

It sounds like there's too much eyeing your yummy desert rose leaves, doesn't it. Although pest control can be quite a headache, it also means your plants are attractive. Otherwise, visitors wouldn't come visit them. From one perspective, this is a natural pattern.

Also, control the water amount you give your plants. All of these yellowing signs are very similar for young seedlings & bigger adenium. Sometimes, during the rainy season, the adenium leaves may get burned at the tips. If the plant is strong, it will replace them with new leaves. It will be okay and you have nothing to worry about in this case. Make sure no rotting is happening in the roots or caudex.

Once you know where the yellowing is going & some interacting factors around it, you can save your plants. Good luck & we hope that the plants will recover. They will.

Thanks to:

• Hong Quan - Su Canh Binh Duong (2)
• Diet Con Trung
• Black Gold
• Quoc Thinh Le
• Hoa Su Kim Thu Binh Duong
• Phan Thanh Quang
• Mark A. Dimmitt

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