Lantana – scientific name Lantana camara, of the family Verbena – comprises 150 species of perennial flowering plants. Native to the tropical regions of the Americas and Africa, their dainty flowers enjoy an extended bloom time. They also thrive in the Australian-Pacific regions and in the southern and northeastern parts of India. Unfortunately, they also suffer their share of conditions that may cause their leaves to turn yellow.
Lantana leaves turning yellow: What are the causes?
Premature dormancy
One of the reasons Lantana leaves turn yellow could be premature dormancy. The plants may go dormant at the first chill or frost, even though it is not yet winter. The yellowing leaves could be the plant’s reaction to the first signs of winter, although that is not necessarily the case. If the days warm up again, the plant’s leaves may stop yellowing.
Lantana plants are perennial plants that thrive in warm, frost-free climates. They are extremely drought-tolerant but unable to tolerate cold weather and may die if exposed to frost.
Incorrect cultural care
Yellowing lantana leaves could also be due to improper cultural care. These plants thrive in warm weather and well-draining soil, so if these elements are not present, the plants will not grow well.
Fortunately, treating yellow leaves due to improper care is entirely possible. Place them in a bright spot where they can soak up the sun, and ensure they are planted in suitable soil.
Diseases such as Botrytis blight
Another cause for yellowing lantana leaves is a disease called Botrytis blight, or gray mold. This fungal disease, prevalent in regions with high humidity, also affects the buds, flowers, and bulbs of plants. The extent of its severity is highly dependent on weather conditions and cultural practices.
Cut off the affected parts of the plant. If this does not work and the remaining leaves continue to turn yellow, dig up the plant and dispose of it at once. This will prevent the spread of the disease to other plants in your garden.
Other diseases that could affect your lantana and cause yellowing leaves include powdery mildew and sooty mold.
Natural variegation
Lantana leaves may be yellow simply due to variegation. Some plants feature variegation in their foliage. This is not a cause for alarm; the variegation is just part of the plant’s aesthetic beauty.
Insects
The presence of insects like lace bugs and aphids could be detrimental to your lantana plants. These critters live on the undersides of leaves, helping them to go unnoticed at first. However, you will eventually notice them as they come in swarms. Lace bugs are grayish, at least ⅛ inch in length, and have a lacy-looking shield.
Eradicate these pests using Malathion, Sevin or neem oil. Repeat the spraying process around seven to 10 days apart.
Overwatering
Lantana leaves could also turn yellow due to overwatering or incorrect watering practices. These plants do not like moist soil and too much water could drown the roots.
Over-fertilization
Spoiling your plants with fertilizers will do them more harm than good. Fertilizer burn could eventually lead to yellowing and dropping of foliage. If you are using herbicides, do not let the spray drift onto the foliage of other plants. Pelletized weed killers can also aggravate the problem; if you notice that pellets have fallen on the ground above the root system, damage may occur.
Conclusion
Lantana plants are drought-resistant and popular for their brightly colored flowers and extended bloom time. They also suffer from diseases and conditions that cause yellowing leaves. Causes may include overwatering, pests, premature dormancy, over-fertilization, variegation, or disease.
Image: istockphoto.com / Maksudur Rahman Rahat