Passion fruit leaves turn yellow when the plant is stressed due to an environmental factor or a negative change in its living conditions. The first step towards fixing the problem is correctly identifying the cause of the discoloration.
The most common causes of passion fruit leaf yellowing are underwatering, insufficient fertilization, low temperatures, pests and diseases.
In this article, we will discuss the different causes of yellowing passion fruit leaves and how to remedy each one.
Why are my passion fruit leaves turning yellow?
Underwatering
Passion fruit plants prefer to be planted in the ground, but they can still be grown in containers, especially in places that get cold winters.
This plant grows very quickly and needs frequent watering to grow, from spring all the way until the fall.
If you let the soil dry out completely, the leaves on the passion fruit vine will turn yellow, then brown, dry up and fall off.
Passion fruit plants are more susceptible to drying out when they are grown in containers, because the container heats up under the sun. Because of the heat, the water in the container evaporates much more quickly.
To prevent the plant’s soil from drying out, check the soil in the container every other day. If the soil is dry to the touch, water the plant. You can also help keep the soil moist for longer by applying a layer of mulch on top of the soil around the plant.
Insufficient fertilization
You need to fertilize your passion fruit plant regularly because they grow very quickly. Fertilizing the plant will help sustain its growth as well as encourage flowering. If the plant’s soil has low nutrient levels, its leaves will turn yellow. Low nutrient uptake will also affect the flowering of the plant, as well as its fruit yield.
To keep the plant’s leaves green and healthy, give it a total of three pounds of fertilizer a year. Divide this amount by four and space out the fertilizer applications from spring until the fall season. Scratch the fertilizer into the soil surrounding the plant, being careful not to disturb the roots. Water the soil well after feeding the plant. You do not need to fertilize the plant during the winter since this is when the plant naturally grows the slowest.
Low temperatures
Frost could be another reason your passion fruit leaves are turning yellow. If the plant is exposed to cold temperatures for extended periods, the leaves may dry up and the plant could die.
If you live in a place where you get very cold winters, bring the passion fruit plant indoors in the fall, even before winter starts, and place it in a sunny window that gets bright sunlight.
If you have milder winters, place the plant in a west- or south-facing window so that it can get warmth in the occasionally cold weather. You can also place the plant on your porch or covered patio for the same result.
If the plant is in your garden, you can protect it from the frost by covering it loosely with burlap.
Pests and disease
One of the most common diseases to infect passion fruit plants is the cucumber mosaic virus. One of the symptoms of this condition is the presence of yellow patches on the leaves. The leaves will eventually curl up and die. This virus is carried by aphids, and these insects can also cause damage to the leaves by feeding on them. Unfortunately this disease does not have a cure, so you will have to dispose of it to avoid the spread of disease to other plants.
If you see aphids on your plant, you can get rid of them using insecticidal soap. Dilute six tablespoons of soap in a gallon of water and spray the plant until it is dripping wet. Repeat the treatment every two weeks for as long as you still see aphids on the plant. Wear protective clothing, such as gloves, when you spray the plant.
Passion fruit plants can also get infected by fungi which result in yellowing and wilting leaves. Fungi thrive in cool and moist areas, so place the plant in a warm place where it can get sunlight.
What other problems can a passion plant encounter?
Leaves and fruit have spots
When your passion fruit plant’s leaves and fruit have spots on them, it is most probably caused by the Alternaria passiflora fungus. This disease leaves spots on the fruits, leaves and stems of the plant. The spots will enlarge, with a light-colored center. This infection will spread until the plant wilts and the fruits collapse.
The spots on the fruits will start as small as pinpricks, and will grow into lesions with brownish centers. The lesions will spread, consuming the entire fruit until it shrivels and drops off the vine.
Shrivelled fruits
If the fruits of the plant are shrivelled while still on the vine, this could be due to fruit fly damage, insufficient irrigation, boron deficiency, poor pollination or bug damage.
Make sure your plant has all the nutrients it needs and remove any pests as soon as you see them.
Malformed fruits
When your passion fruit looks lumpy and deformed, it is most likely due to the passion fruit woodiness virus. This often causes mottled and yellow leaves.
A boron deficiency and fruit flies can also cause malformed fruits.
If you see these symptoms in your plants, it is best to dispose of the infected plants to avoid spread of infection.
Fruit dropping off the plant
If the fruit keeps dropping off of your plant prematurely, it may be due to mite damage, fruit flies, a fungal infection, irregular watering or a sudden drop in temperature.
Insects like the passion fruit vine hopper that feed on the vine can also cause fruit to drop. The best way to avoid infestation is to check your plants regularly for the presence of any pests.
When a plant lacks vital elements, it can also lead to fruit drop. Passion fruit plants need certain nutrients and minerals to support fruit production. If the plant is running low on nutrients, it will instinctively drop its fruits in order to conserve its resources to keep the main plant alive.
The plant is flowering but has no fruit
If your passion fruit plant has no problem flowering but is not yielding any fruit, it can be due to several reasons. The most common ones are extended gloomy weather, boron deficiency, too much rain, extreme temperatures, or poor pollination.
The plant produces fruit, but they have no juice
This can be attributed to the plant not getting enough nutrients or water during its growing period, among other reasons.
Remember that this plant is insatiable and needs regular watering and feeding, so keep its soil moist to keep it happy. Failing to provide the plant’s basic needs is enough to discourage it from producing healthy fruit.
You should also remember that passion fruit plants only start to produce proper fruit in their second year, especially if they are grown in colder climates.
Conclusion
Passion fruit leaves turn yellow when the plant is stressed due to environmental factors or because of a negative change in its living conditions. The best way to fix this problem is to correctly identify the cause of the leaf discoloration.
The most common causes of yellowing passion fruit leaves are underwatering, insufficient fertilization, low temperatures, pests and diseases.
Image: istockphoto.com / quangpraha