Q: I bought a mandevilla vine last spring, and I have brought it into my southeast-facing apartment, where it is doing well, but some of the leaves seem to develop spots, and then after a day or so they turn yellow and fall off. I cant see anything on the leaves, even with a magnifying glass, although when I rub the top of the leaves my fingers get a little bit sticky. What could the problem be, and what should I do about it?
Reviews and recommendations are unbiased and products are independently selected. Postmedia may earn an affiliate commission from purchases made through links on this page.
Q: I bought a mandevilla vine last spring, and I have brought it into my southeast-facing apartment, where it is doing well. I have five cuttings from it that are all growing nicely, but some of the leaves seem to develop spots, and then after a day or so they turn yellow and fall off. I can’t see anything on the leaves, even with a magnifying glass, although when I rub the top of the leaves my fingers get a little bit sticky. What could the problem be, and what should I do about it?Advertisement 2Story continues belowThis advertisement has not loaded yet, but your article continues below.
Mandevilla is a popular tropical vine grown for its showy flowers. However, a common problem that gardeners face is yellowing leaves on mandevilla plants. Yellowing leaves indicate the plant is stressed and not able to produce enough chlorophyll. This can happen due to various reasons.
In this article, I will explain the main causes of yellowing mandevilla leaves and how to fix the problem With proper care and troubleshooting, you can enjoy lush green growth and abundant blooms on your mandevilla vine
Understanding Why Mandevilla Leaves Turn Yellow
The mandevilla plant requires full sun, warm temperatures, adequate water and nutrition to thrive If any of these requirements are not met, the leaves will start to turn yellow
Yellowing usually starts with the oldest leaves near the base of the plant. It indicates that the plant is unable to produce enough chlorophyll due to some kind of stressor
Chlorophyll is the green pigment in leaves that allows photosynthesis. When the plant has inadequate chlorophyll, it cannot absorb enough sunlight to create energy through photosynthesis. As a result, the plant becomes stressed and the leaves turn yellow.
Some yellowing of lower leaves is normal as part of the plant’s natural cycle. But if many leaves are yellowing, it signals a more serious underlying problem.
6 Main Causes of Yellow Mandevilla Leaves
Here are the most common reasons mandevilla leaves turn yellow and how to fix them:
1. Improper Watering
Irregular or insufficient watering is the number one reason for yellowing mandevilla leaves. These tropical vines need moist soil at all times. If the soil dries out completely, the leaves will start to yellow and curl.
On the other hand, overwatering can also cause yellow leaves due to damaged roots and root rot. The soil must drain well to prevent waterlogging.
Solution: Water mandevilla vines when the top 1-2 inches of soil is dry. Provide 1-2 inches of water weekly. Water less frequently in winter. Improve drainage if the soil is remaining soggy.
2. Nutrient Deficiency
Lack of nutrients like nitrogen, iron, manganese and magnesium can cause yellowing leaves. Iron deficiency shows up as yellowing between the veins while the veins remain green.
This happens when the soil pH is too high and the plant cannot absorb iron properly. Mandevillas prefer a slightly acidic pH between 5.5-6.5.
Solution: Test your soil pH and amend it if needed. Fertilize plants with a balanced fertilizer every 2-4 weeks in spring and summer. Avoid over-fertilizing which can burn the roots.
3. Improper Light
Mandevilla vines thrive in full sunlight. Too little light will starve the plant of energy needed to produce chlorophyll and grow. This leads to pale yellow leaves.
Solution: Place mandevilla in the sunniest part of your garden or patio. Move indoor plants next to a bright sunny window. Use grow lights to supplement natural light if needed.
4. Extreme Temperatures
Exposed to cold drafts and temperatures below 50°F (10°C), mandevilla leaves turn yellow and plants fail to thrive. On the other hand, intense afternoon sun in summer can also scorch the leaves.
Solution: Avoid cold drafty locations and protect outdoor mandevillas when frost is expected. Provide shade from hot afternoon sun. Move indoor plants away from heat vents and drafts. Maintain ideal temperatures between 70-80°F (21-27°C).
5. Pest Infestations
Sucking pests like mealybugs, aphids, and spider mites can infest mandevilla vines. They feed on plant sap, causing the leaves to yellow and drop off. Check the undersides of leaves and stems for any white, cottony deposits or tiny insects.
Solution: Remove pests with a strong jet of water. Wipe leaves with neem oil or insecticidal soap. Apply horticultural oils or systemic insecticides for heavy infestations. Isolate and treat infected plants to prevent spreading.
6. Disease Problems
Bacterial and fungal diseases can also lead to yellowing mandevilla leaves. Common diseases are southern blight, bacterial leaf spot, alternaria leaf spot and phytophthora root rot. These are caused by pathogen infection due to wet conditions.
Solution: Improve drainage and avoid overhead watering which spreads pathogens. Remove infected leaves immediately. Treat with appropriate organic fungicides. Destroy severely infected plants. Sterilize pots before reusing.
How to Fix and Care for Yellowing Mandevilla Leaves
If your mandevilla leaves have already started turning yellow, here are some tips to rejuvenate the plant:
-
Prune off any severely yellow or dead leaves and branches to focus the plant’s energy on new growth.
-
Check the roots – if they are black and mushy, recover any healthy roots and repot the plant in fresh well-draining soil.
-
Move the plant to a location with more appropriate sunlight and temperatures.
-
Water thoroughly only when the topsoil is partly dry. Reduce watering in winter.
-
Fertilize every 2-3 weeks with a balanced liquid fertilizer to replenish nutrients.
-
Monitor for pests and treat any infestations. Be proactive with neem oil sprays.
-
Consider repotting in a larger container if the plant is root bound.
-
Increase humidity with a pebble tray or misting. Mandevillas enjoy 40-50% humidity.
With time and care, the mandevilla leaves will regain their lush green color and support vibrant blooms. Be patient and consistent with proper care. The plant will rebound once its needs are met.
Preventing Future Yellowing of Leaves
Prevention is the best cure when it comes to plants. Here are some tips to grow healthy mandevillas with minimal leaf yellowing:
-
Select a spot with full sun, such as a south facing wall or trellis. Morning sun is adequate for indoor plants.
-
Use well-draining potting mix and containers with drainage holes. Repot every 2-3 years.
-
Water thoroughly only when topsoil is partly dry. Reduce watering frequency in winter.
-
Mist leaves and maintain 40-50% humidity for indoor plants. Install a humidifier.
-
Feed with balanced fertilizer every 2-4 weeks during active growth. Do a soil test before applying nutrients.
-
Check frequently for pests like spider mites under the leaves. Take action before they multiply.
-
Prune back overgrown vines after flowering to encourage new growth. Remove dead or diseased foliage promptly.
-
Bring outdoor mandevillas indoors before frost strikes. Avoid cold drafts and maintain ideal temperatures.
By providing adequate sunlight, moisture, nutrients and pest control, you can have healthy mandevilla vines with minimal leaf yellowing. Pay attention to the plant’s needs and take prompt corrective action whenever you notice any problems.
Yellowing mandevilla leaves indicate that the plant is stressed and unable to produce enough chlorophyll. This commonly occurs due to improper watering, insufficient light, cold temperatures, pests and diseases. With some troubleshooting and adjustment of care, the plant can recover its lush green foliage.
Ensure mandevillas get adequate sunlight, regular fertilization, even moisture and protection from extreme weather. Monitor for pests and treat promptly. With the right growing conditions, mandevilla will reward you with incredible flowers throughout the season.
Reasons for Yellow Mandevilla Leaves
There are a number of causes to a mandevilla plant turning yellow. Below are some of the most common reasons for yellow mandevilla leaves:
Improper watering can cause yellow leaves on a mandevilla. Too much or too little water can be reasons for yellow mandevilla leaves. Soil should remain moist, but not soggy. If roots are soggy, remove the plant from the container and remove as much of the soggy soil as possible. Repot in fresh soil that is barely moist. Waterlogged roots are a common reason for the mandevilla plant turning yellow, as is dried out soil. If the plant is getting too little water, leaves will curl as they yellow. Water if necessary. Bottom watering can be effective in this case, as the plant will only take up the water it needs.
Lack of the right fertilizer can also be responsible for yellow mandevilla leaves. If it has been a while since feeding your plant, then its likely your mandevilla plant turning yellow is due to a lack of nutrients.
If the mandevilla plant is older, some yellowing leaves are to be expected as they die to make room for new growth. A few yellow leaves on a mandevilla can be removed. When removing the yellowing leaves, take a close look at the rest of the plant, particularly on the underside of the leaves and in the axils of the leaves and stems where insects are common.
Insects can cause yellow leaves on a mandevilla. Mealybugs, spider mites, and aphids can weaken plants and are sometimes reasons for yellow mandevilla leaves. If mealybugs have taken up residence on the plant, small spots of white cotton-like material will be visible. This houses the eggs of the mealybug, where hundreds may hatch and feed on the plant. Regardless of the pest, treating yellow leaves on mandevilla is done effectively with an insecticidal soap spray or a horticultural oil such as neem oil. Large infestations may require a systemic insecticide when treating yellow leaves on mandevilla. Until you determine what is causing yellow leaves on a mandevilla, seclude it from other plants so insects or disease do not spread to healthy plants. You can then determine the problem and begin treating yellow leaves on mandevilla.
Sometimes the reasons for yellow mandevilla leaves are from disease pathogens, such as Ralstonia solancearum, the bacterial pathogen that causes Southern wilt. Plants may be fine in cool weather and when temperatures warm, pathogens may be reasons for yellow Mandevilla leaves. Plants with Southern wilt eventually die. All plant material, soil, and containers should be discarded to avoid the spread of the pathogen. Too much sun is often blamed because the gardener does not ask, “Why are mandevilla leaves turning yellow?” until temperatures have warmed, and the plant has been located in full sunlight.
Sign In or Create an AccountEmail Address
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. My question is, as this will be the plant’s third year, should I change the soil? Also, will any type of potting soil work, or does it require something special? I have just fertilized it during the growing season. Also, will the soil surrounding the mandevilla vine need to be changed too, or should I just leave it and fertilize 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. When you water, do so in the sink, allowing the water to run out of the pot and down the drain.
Get the latest headlines, breaking news and columns.
- There was an error, please provide a valid email address.
By signing up you consent to receive the above newsletter from Postmedia Network Inc.Thanks for signing up!
A welcome email is on its way. If you dont see it, please check your junk folder.
The next issue of Headline News will soon be in your inbox.
We encountered an issue signing you up. Please try againArticle contentAdvertisement 3Story continues belowThis advertisement has not loaded yet, but your article continues below.Article content
A lack of water, or allowing the plant to dry out too much between waterings, can also cause problems. 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. I have had a few readers tell me that their finger is not sensitive enough to detect the moisture, so I ran across another technique that you can try that involves using 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. If it has only slightly changed colour you will need to check the soil again in a few days. 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 whitefly can cause the stickiness that you are describing, but since you examined the leaves closely 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. Place a layer of the moistened soil in the bottom of the new pot, place the rootball of the plant into the new pot, and then add more moistened potting mix around the sides of the rootball. This method keeps the transplant shock to a minimum.
Q: I have a calamondin orange tree. My cat was sharpening his nails on it and stripped the tree of leaves, and I am wondering if the cat has killed the tree. I put the tree in my west-facing window, then in the basement in the dark for four weeks. If I bring it back to the west-facing window, what are the odds of it growing again? I am hoping that it will come back, so if you have any suggestions I would appreciate it.
A: The best answer I can give you is that if it were me I would certainly try it. 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 would even consider putting it outside when all danger of frost is gone.
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 [email protected]. To read previous columns, go to edmontonjournal.com/filipskiArticle contentShare this article in your social networkTrending
This website uses cookies to personalize your content (including ads), and allows us to analyze our traffic. Read more about cookies here. By continuing to use our site, you agree to our Terms of Use and Privacy Policy.
Mandevilla (Dipladenia) sanderi – yellow, dying leaves? (Part 1/3)
FAQ
How do you fix yellow leaves on mandevilla?
Repot in fresh soil that is barely moist. Waterlogged roots are a common reason for the mandevilla plant turning yellow, as is dried out soil.Feb 13, 2023
What does overwatered mandevilla look like?
If the roots are brown and resemble overcooked noodles, you’ve gone too far with the water. Mushy roots are a cry for help; they need air, not a swimming pool.Mar 1, 2024
How often do you water a mandevilla?
Wait until the soil is almost fully dry before watering again. This will typically be once a week.
How do you treat yellow leaves?
Leaves that are Yellow, Curling, and Drooping
To fix this, the solution is to water your plant to evenly and thoroughly saturate the soil. Some plants may perk back up within a few hours after watering, while others may require a few days.