The genus Lantana is one of the more popular ones in the Verbenaceae family, and its 150 or so plants have often been referred to as shrub verdanas.
In regions with warmer climates, lantanas can be cultivated as perennials, while in colder climates, they are grown as annuals.
Lantana plants are relatively easy to care for and can have very heavy foliage and blooms.
But easy to care for doesn’t necessarily mean foolproof, and there are times your lantana will get sick.
One key sign of illness is curling leaves, and often, the direction of the curl (upwards or downwards, AKA wilting) can tell you a lot about what’s wrong.
If you’re experiencing curled leaves, don’t panic. Diagnosing the problem can usually lead to your lantana being happy and healthy again.
Why is My Lantana Leaves Curling?
Your lantana could have curling leaves for several reasons, usually related to nutrition (yellow leaves), care, or an infestation or infection.
Here are the most common reasons, how to diagnose them, and how to treat them.
Heat and Sunlight
Too much of a good thing isn’t good. For example, direct sunlight or too much heat can cause leaves to curl upwards on Lantanas growing indoors.
In the case of full sun, you might see signs of scorching on older leaves and stunted growth on younger ones.
In the case of heat, your plant’s leaves are curling up to conserve their water, which is mainly sweated out to raise local humidity.
In both cases, try to provide your plant some more shade by moving it to a spot with bright, indirect sunlight or by placing some afternoon shade over an outdoor plant.
Six hours of direct sunlight per day is enough for the lantana.
Herbicidal Poisoning
If you prefer using weed killers over hand-picking or complimentary gardening, your lantana may have accidentally suffered chemical burns.
This can easily happen if you spray too close to the plant or if a breeze picks up droplets.
Upward-curving leaves are often the first symptom, and if you see this within a day or two of using an herbicide, you’ll need to hose down the plant to get any chemicals off.
Once clear of chemicals, give the plant some fertilizer to help it recover, and note that any existing damage may have to be pruned away.
To combat toxicity from excessive fertilizer or salt buildup, thoroughly flush the soil around the lantana plant with water to remove the problematic substances from its root zone.
Infections
Your plant’s leaves will often curl when it’s suffering from an infection, with an upwards curl usually symptomatic of a viral infection and a droop or downwards curl being the result of many fungal infections like sooty mold.
There’s a good chance you’ll also see other symptoms, such as discolorations, blisters, or abnormal growth.
In fungal diseases, a fungicide or (depending on the fungi) neem treatment will help.
Neem foliar sprays can combat many surface fungi, while the soil soak can combat fungi that break through the plant’s surface.
Unfortunately, viral infections are often far more severe, and many are incurable.
In such cases, you may have to sacrifice the entire plant, although sometimes you can safely prune away infected stems before the disease spreads.
Note that you will also need to check any nearby plants for signs of infection.
Infestations
There are a lot of nasty little vampires out there that love chewing on plant parts.
Aphids, lace bugs, mealybugs, whiteflies, and spider mites are common pests that can infest lantana plants.
This can result in the leaf drop or leaves curling upwards as they’re drained.
Infestations won’t usually kill your lantana but can lead to secondary infections or spread to other plants.
You’ll usually be able to spot the bugs on the undersides of leaves.
Treatment is generally pretty easy using insecticidal soap made from neem oil, either as a foliar spray or, preferably, as a soil soak.
Note that the neem soak takes longer to show its effects than the spray, but one dose protects your plants for up to 22 days, and it can be used every 2 to 3 weeks as a non-toxic preventative.
Also, consider attracting beneficial insects like butterflies, bees, and hummingbirds to help keep pest populations at bay.
Malnutrition
Plants need several nutrients to grow properly.
Nitrogen is one of the Big Three, and a deficiency can cause the older leaves to curl upwards as the plant redirects its available nitrogen to the new growth.
Meanwhile, copper, iron, phosphorus, and potassium deficiencies can result in the leaves curling downward or drooping.
Ensure the fertilizer you’re using has the right NPK content and that you’re feeding the plant according to the package instructions.
A soil test will give a check of the nutrient levels.
Solving this problem is often as easy as adding compost, changing the fertilizer, or how often you feed the lantana, or using an iron or copper supplement.
Poor Lantana Watering Habits
One of the few things that can kill your plant is that excess water will lead to root rot, and often, your first symptom is the leaves curling upwards.
Root rot is a serious condition that can be treated if caught early enough but deadly if ignored.
Meanwhile, a downward drooping and possibly brittle texture is a sign of underwatering.
Avoid both conditions: too much water or underwatering with the soak-and-dry method of watering.
Lantanas require moderate irrigation and prefer moist, well-drained soil.
Simply put, use your finger to test the dryness of the soil and only water when it’s dry about 1″ to 2” inches down.
Ground-based plants should be watered when the soil is dry to the touch, as they usually have better drainage than those in containers.
Always water slowly until you see the water begin to seep from the drainage holes (or enough on-ground plants to equal 1” inch per week after accounting for rainfall). Water lantanas from the ground level during the morning hours.
Note that in severe cases of overwatering where the soil is soggy, you may also need to transplant the lantana to a fresh pot of soil, pruning away any diseased roots in the process.
Regularly inspect the soil moisture level and adjust your watering frequency accordingly.
Drought
Another factor for curling leaves can be because of drought seasons.
Lantana camara is known for being drought-tolerant plants, but prolonged periods of drought can still affect its health.
Regular watering is necessary to maintain drought tolerance and prevent leaf curling.