| I have a plumbago in my conservatory. It is flowering well, but quite a few of the leaves are going yellow, then brown. Many of the leaves, even if green and healthy, seem to have a fine powdery coating on the underside only. It doesn't look like mildew. I have tried giving it a dose of sequestrene in case it had chlorosis, but so far no response. I haven't been able to see any 'bugs' causing the problem. Any ideas? |
| A powdery coating almost always means the fungal disease called powdery mildew. This can grow when nighttime temperatures are cold and daytime temperatures are high and is especially active where air circulation is poor. I'd isolate the plant, try to keep water off the leaves, prune back the affected plant parts and increase air circulation. Hope your plumbago pulls through! |
