Why Are My Lupin Leaves Curling? [5 Reasons & How to Fix]

Lupins are a favorite to many due to their breathtaking flowers and unique leaf arrangement. Like in other plants, you’ll know that your lupins have problems from the changes in their leaves. In most cases, the leaves will start curling, and you might be wondering why.

Curling in lupin leaves can be due to infestation by pests and diseases, under-watering, or excess heat. To determine the exact cause, it would help to observe the leaves keenly and identify other symptoms. Sometimes you might require the help of an expert, especially where diseases are involved.

This article explores a few topics on your lupin plant health and signs of underlying problems causing curling leaves. We will also discuss how to avoid or control the situation and adequately care for your lupins to prevent leaf curling. So, read on to learn more!

Table of Contents

Reasons for Curling Lupin Leaves

Leaf curling is just a sign that your lupins are suffering. However, identifying the reason is the only way to help them before it’s too late.

Like many other plants, lupins are vulnerable to pests, diseases, and weather variations, among other factors that can cause the curling of leaves.

Here are the common factors that cause curling in lupins:

1. Fungal Diseases

Among the most prevalent fungal diseases in lupins is lupin anthracnose. The Colletotrichum lindemuthianum fungus is behind this disease which drains plants of their nutrients and kills plant tissue such as leaves.

It affects young seedlings and mature plants. Other symptoms include drying leaves around the center, which causes curling or corkscrewing. This disease spreads through water splashes, carrying the fungal spores from one plant to another.

If left untreated, it can cause the death of infected plants.

2. Viral Disease

The cucumber mosaic virus (CMV) threatens lupins, especially in areas with high rainfall, such as Florida and North Carolina. Aphids are the primary vectors of this virus, but they can also originate from infected seeds. In addition to curling, the leaves can appear pale, and plants can experience stunted growth.

Lupin leaf curl virus is another virus-like disease, and the Geminivirus is the common causative agent. Whiteflies are the main vectors of Lupin leaf curl, so it is highly contagious.

The main symptom of this infection include:

Down curling of leaves
Reduced flowering
Some older leaves turn purple

Note: You might also notice stunted growth and thickening of veins in your lupins.

3. Pests

Lupins are attractive to several pests, including bugs. For instance, whiteflies are white-flying insects that attack the underside of lupin leaves. They reproduce fast, increasing their population within a short time.

The females lay eggs, and the hatched larvae feed on lupin leaves. They damage the leaves by sucking sap, causing yellowing and curling. These insects breed in large numbers during warm weather and can affect your plants all year round.

Aphids are also sap-sacking insects that can cause leaf curling in your lupins. The lupin aphid variety is gray with a soft body that quickly crashes on touch. Like white flies, they attack the leaves’ undersides, where they form colonies.

Apart from curling, you might also notice tiny ants going up and down the plant. The sugary substance attracts the ants that aphids produce after sucking the leaf sap. Without immediate interventions, this infestation can spread fast, causing irreparable damage.

4. Under Watering

Any plant requires enough water to survive. If you aren’t watering your lupins enough, this can result in leaf curling. The leaves might fold up to conserve the little water in their system.

However, lupins don’t require much water, even though they thrive in areas with rainfall.

Otherwise, you need to water it with one inch of water once a week. But too much water can cause water logging, leading to the growth of fungi hence root rot.

5. Excess Heat

Heat stress can also cause leaves to curl in your lupins. If you live in dry areas, your lupins might wrap their leaves to preserve moisture. Dry areas experience higher transpiration rates and increased water loss.

Therefore, lupins fold their leaves to reduce the surface area under direct sunlight to prevent dehydration. In such cases, you’ll notice the leaves return to normal in the evening and throughout the night.

Read Why Are My Lupin Leaves Turning White?

How To Avoid and Control the Infestations

There’s little you can do to control viral diseases like the cucumber mosaic virus because aphids and infected seeds spread it. However, it would help to take precautions because the onset of infection may result in massive loss.

So, here are ways to protect your lupins from infestations:

Minimize Water Splashes

Water splashes spread most fungal diseases. The water picks the spores from the soil and lands them on the leaves from where they lay.

The best way to avoid lupin anthracnose is by minimizing splashes from one plant to another. Instead of overhead irrigation, utilize a drip or a can for targeted watering to reduce splashes.

Additionally, placing your lupin plants on elevated benches helps to reduce contact with the ground. Hence, consider using flower pots and other containers if you only have a small population of plants.

And if you’re sure your plants have anthracnose, it’s best to use the most suitable fungicides to kill the fungi before spreading further.

Deal With Insect Infestations

Controlling whiteflies isn’t easy because they come almost suddenly and reproduce quickly. However, you can try washing them off using a high-pressure water pump. You can also use a hand-held vacuum cleaner to suck them from the leaves’ undersides.

Then you’ll need to remove the highly infested leaves to kill the eggs. Since they fly fast, you must repeat the procedure every two days until the population is over.

Alternatively, you can use chemical controls, especially with heavy infestations. The least toxic chemicals include horticultural oil and insecticidal soap. If this doesn’t work, you can use systemic pesticides with the help of an extension officer.

Always adhere to state regulations before using pesticides. In Florida, for instance, you must have a pesticide license to purchase or use pesticides.

Controlling aphids requires washing them off the leaves using a high-pressure water pump. You can also remove infested leaves and burn or bury them. Also, you can use non-restricted pesticides, but they aren’t the best remedy.

Note: Pesticide use should be the last solution to control lupin pests and diseases. Since the plants are flowering, they attract many beneficial insects such as bees, butterflies, pirate bugs, and some beetle species that act as pollinators. So, chemicals can be detrimental to these organisms.

Water Your Lupins Properly

Controlling under-watering involves watering the plants with enough water, especially if you live in drier areas. Also, as mentioned earlier, ensure the soil drains well to avoid waterlogging, which can cause other severe problems for your flowery friends.

Keep Your Lupins in a Shaded Area

The only solution for heat stress is providing shade for your plants. If you’re growing them in pots, you can relocate them to a cooler place or construct a DIY shade for the ones on the ground.

If you’re dealing with a large plantation, ensure they remain well-watered to compensate for the high water loss, especially in hotter areas such as Texas and Arizona.

Conclusion

Lupins are beautiful flowers but vulnerable to pests and diseases, causing their leaves to curl or die. Ensure you observe them properly so you can’t act immediately to solve your potential problem. Most problems include fungal and viral diseases and pests such as aphids and white flies. These insects feed on the plants’ sap and sometimes introduce other pathogens.

The best way to control them is by using biological methods, but you can use pesticides in case of high infestation. However, these are unsafe because they kill even the pollinators essential in the growth of lupins.