Q: I bought a mandevilla vine last spring and put it in my southeast-facing apartment. It’s doing well there, but some of the leaves get spots and then turn yellow and fall off after a day or so. Even with a magnifying glass, I can’t make out anything on the leaves. However, my fingers get a little sticky when I rub the tops of the leaves. What could the problem be, and what should I do about it?.
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I bought a mandevilla vine last spring and put it in my southeast-facing apartment. It’s doing great there. It gave me five cuttings that are all growing well, but some of the leaves get spots and then turn yellow and fall off after a day or so. Even with a magnifying glass, I can’t make out anything on the leaves. However, my fingers get a little sticky when I rub the tops of the leaves. What could be wrong, and what should I do about it?Advertisement 2Read more belowThis ad hasn’t loaded yet, but your article continues below.
As a passionate gardener, I find few sights more distressing than looking out at my beautifully flowering mandevilla vine and seeing its glossy green leaves marred by yellowing. Those sunny yellow splotches marring the foliage certainly grab your attention, but not in a good way.
While some yellowing of lower leaves is normal as the plant ages, extensive yellowing of young leaves usually indicates an underlying issue When mandevilla leaves are turning yellow, it typically signals that something is off with your care regimen
The good news is that yellowing leaves can often be reversed if caught early. Here is an in-depth look at why mandevilla foliage turns yellow and what you can do to restore your plant’s vibrant green luster.
Common Causes of Yellow Mandevilla Leaves
Yellow leaves on your mandevilla are most frequently caused by
- Overwatering or underwatering
- Low humidity
- Intense sunlight
- Poor drainage
- Nutrient deficiencies
- Pests like spider mites
- Diseases such as southern blight
- Natural leaf aging
Correcting Environmental Issues
Leaf yellowing from environmental factors like light, water, and humidity can often be corrected with a few simple adjustments:
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Move pot to a shady spot if in intense midday sun Mandevillas prefer bright indirect light
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Check soil moisture regularly and water only when the top inch is dry.
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Improve drainage by repotting in a container with holes using fresh, well-draining soil.
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Increase surrounding humidity by misting frequently or placing on a pebble tray.
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Apply a balanced liquid fertilizer monthly to provide missing nutrients if deficiency is suspected.
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Leach pot once a month to remove any buildup of salts from fertilizer.
Treating Pests and Disease
If you suspect pests or disease, take prompt action:
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Isolate plant and prune off any yellow, mushy, or pest-infested areas.
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Check all leaf surfaces thoroughly for signs of mites, whitefly, or other pests.
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Apply neem oil or insecticidal soap weekly to control infestations.
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Remove and destroy severely damaged leaves and branches.
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For possible southern blight, improve drainage and apply appropriate fungicide.
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Remove any remaining plant parts at end of season. Sterilize pot before reuse.
When Yellowing is Normal
Some yellowing of lower leaves is perfectly normal on a mature mandevilla:
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As a self-cleaning vine, old leaves turn yellow and drop off naturally. This is not a cause for concern.
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Lower leaves may yellow and fall in autumn as growth slows. This is the plant preparing for dormancy.
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Leaves closest to blooms may yellow as production of flowers takes precedence for the plant.
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An early light frost can cause minor yellow spots on some leaves. Protect or move indoors if more frost is expected.
As long as the yellowing is only affecting a few lower leaves and the remaining foliage looks healthy, the plant is likely just shedding older leaves and no action is required. But keep an eye out for spreading yellowing which indicates a problem.
Preventing Future Yellowing Issues
With proper care, you can avoid many common causes of yellow mandevilla leaves:
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Grow in a spot with plenty of bright, indirect light.
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Maintain indoor temperatures above 60°F in winter and below 90°F in summer.
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Water thoroughly only when top inch of soil is dry. Provide saucer drainage.
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Mist frequently to maintain 50-70% relative humidity around the plant.
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Repot in a container with drainage holes using fresh potting mix every 2-3 years.
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Feed with a balanced liquid fertilizer every 2-4 weeks during active growth.
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Inspect regularly for pests and treat promptly with neem oil if found.
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Prune off spent flowers and unhealthy leaves at the base to encourage new growth.
By correcting any issues promptly and providing consistent, proper care, you can get your mandevilla back to forming perfect green growth rather than yellow leaves. Pay close attention to your plant and act quickly if you notice yellowing spreading. With early intervention, you can restore the spectacular beauty of your mandevilla’s lush green vines and colorful blooms.
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Also, last winter I kept an alstromeria plant indoors, and it bloomed beautifully all summer. It seems to be doing well this winter as well. This is the plant’s third year, so I want to know if I should change the soil. Also, will any potting soil work, or does it need something specific? I fertilized it while it was growth. Also, do I need to change the soil around the mandevilla vine or can I leave it alone and feed it during the growing season?
A: Mandevilla leaves typically turn yellow and drop off near the base of the plant. This is quite common with many vines, which lose their older leaves as they grow. However, if your plant is losing leaves in other areas then there is cause for concern. The first thing to check is the amount of water the plant is getting. Too much water can cause a problem, especially if the water is not draining away quickly. Check to make sure the roots of the plant are not sitting in soggy soil. If they are, you might want to look at a pot that offers better drainage. Water your plants in the sink so the water can run out of the pot and down the drain. Article content.
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Not giving the plant enough water or letting it dry out too much between waterings can also be bad. Mandevilla likes to have a moist soil, but never wet. Use your index finger to check. Insert the finger up to the first knuckle. If the soil feels dry it is time to water. Some of my readers have told me that their finger isn’t sensitive enough to feel the moisture, so I found another method that you can try: use a chopstick.
The chopstick should be plain wood and not be treated in any way. Insert the chopstick into the soil, avoiding the roots. Leave the chopstick in place for 10 minutes and then examine it. If it has changed colour or has a watermark, the soil is moist. You’ll need to check the soil again in a few days if the color hasn’t changed much. You can rinse and dry the chopstick to use again, or you can also use a popsicle stick.
The spots you are describing may be a fungal infection called leaf spot. You can treat leaf spot with a garden sulfur spray or a garden fungicide such as Serenade. Mealybugs or whiteflies can make leaves stick together, but since you looked at the leaves very carefully, I think we can rule those out. Advertisement 4Story continues belowThis advertisement has not loaded yet, but your article continues below. Article content.
As for the alstromeria and mandevilla soil, I would change the soil for both plants. You should also consider moving them into to a bigger pot. They do not require any special potting mix, just a good quality one. One tip I would offer when repotting is to moisten the potting mix before using it. A layer of wet soil should be put in the bottom of the new pot. Then, put the plant’s rootball inside the pot and cover the sides with more wet potting mix. This method keeps the transplant shock to a minimum.
Q: I have a calamondin orange tree. My cat used the tree to sharpen his nails and picked off all the leaves. I’m not sure if the cat killed the tree. I put the tree in my west-facing window, then in the basement in the dark for four weeks. What are the chances that it will grow again if I move it back to the west-facing window? I really want it to come back, so if you have any ideas, I’d appreciate them.
A: The best answer I can give you is that I would try it myself. You won’t know unless you do it. I would keep the soil moist but not wet, and be patient. If you see signs of life, I might even put it outside when there is no chance of frost.
Gerald Filipski is a member of the Garden Writers Association of America. He is the author of Just Ask Jerry. E-mail your questions to filipskigerald@gmail. com. To read previous columns, go to edmontonjournal. com/filipskiArticle contentShare this article in your social networkTrending.
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Mandevilla (Dipladenia) sanderi – yellow, dying leaves? (Part 1/3)
FAQ
What does an overwatered mandevilla look like?
How often should mandevilla be watered?
How do I bring my mandevilla back to life?
Why is my Mandevilla turning yellow?
Unless, that is, you see the leaves on your mandevilla turning yellow, in which case, take it as an early sign that your plant needs some extra care and attention. As mandevilla plants are typically grown in containers, the soil is going to need to be changed periodically.
Why does my Mandevilla have leaf spots?
The answer is obvious once you recognize the cause of the problem. Most frequently, it results from the Mandevilla spp. being overwatered. We strongly advise you to remove the damaged plant parts, cut off the diseased roots and leaves, and then repot your plant in a new container with sterile potting soil.
What happened to my Mandevilla plant?
I have a few Mandevilla plants; Alice du pont and they have been growing wonderfully all summer outdoors in containers. All of a sudden a white one started dropping flowers and then leaves were turning yellow and limp like. Not firm and leathery, glossy like when it was happy. It died in 2 weeks.
Do Mandevilla plants need to be changed?
As mandevilla plants are typically grown in containers, the soil is going to need to be changed periodically. If you’ve had your plant in the same soil for a year or two, chances are, the soil’s past its prime. The soil you use needs to be well-draining to prevent the soil from water-logging, which will lead to root rot.