Greetings from the world of Osteospermum! We are a resilient bunch, often called African Daisies, and we generally thrive with minimal fuss. However, sometimes our vibrant, daisy-like flowers are let down by the condition of our leaves. When our foliage looks unhappy, it is our primary way of communicating that our needs are not being met. Here is a detailed look at the common issues that afflict our leaves and what you, our caretaker, can do to help.
When our lower, older leaves begin to turn a uniform yellow and feel soft, we are most likely suffering from over-watering. Our roots, which need to breathe, are suffocating in waterlogged soil. This leads to root rot, preventing us from taking up nutrients and causing the yellowing. Conversely, if our leaves are yellowing, particularly at the tips and margins, and the soil is dry and pulling away from the pot's edge, we are desperately thirsty and under-watered. A lack of key nutrients like nitrogen can also cause a general pale yellowing across our entire foliage.
Seeing our leaves wilt and droop is a clear sign of distress. On a hot afternoon, this might be a temporary wilting to conserve water, and we will perk up in the evening. However, if the wilting is persistent, the cause is almost always related to water. It could be a lack of water, where our cells are simply deflated. More seriously, it could be from over-watering and root rot, where the damaged roots cannot take up any water at all, leaving us paradoxically wilted in wet soil.
Spots on our leaves are a sign of attack or disease. Small brown spots with a yellow halo often indicate a fungal disease like leaf spot, which thrives in damp, humid conditions with poor air circulation. If the spots are more powdery and white, turning leaves brown and distorted, you are dealing with powdery mildew. Dark, mushy spots on leaves and stems suggest a bacterial infection, often exacerbated by overhead watering that leaves our foliage wet for extended periods.
If our new growth is coming in twisted, curled, or distorted, please inspect the undersides of our leaves. You will likely find small, soft-bodied insects like aphids or thrips. These pests pierce our tender tissues and suck out our sap, injecting saliva that causes the abnormal growth. They also excrete a sticky substance called honeydew, which can attract sooty mold. Environmental stress, such as exposure to herbicide drift or extreme temperature fluctuations, can also cause our leaves to curl and cup in protest.
When you see holes chewed through our leaf blades or areas where only the veins remain (skeletonization), the culprits are almost certainly chewing insects. Caterpillars, slugs, and snails find our leaves particularly delicious. They are most active at night or in damp, shaded conditions. They rasp away at our tissue, leaving behind these very obvious physical signs of damage. Left unchecked, they can severely defoliate us, weakening our overall health and reducing our ability to photosynthesize.
