Powdery mildew on honeysuckle
Hi. My honeysuckle has been very happy on the south side of my garage until last fall. I noticed what looks like powdery mildew that quickly spread through the whole plant, even on the stems. Should I prune it right back to ground level this spring? Or leave it and see how the new growth reacts? I live in central Alberta. Cheers.
Powdery mildew is a common problem in honeysuckles. It doesn't over-winter in the plant so there is no need to cut it down. However, all those leaves must be removed as they will re-infect this year's leaves if allowed to linger. PM infection is most common during hot, dry spells - just the opposite of what most people think when they hear mildew. Keys to prevention are regular watering at soil level, not on the leaves, selective pruning to allow better air circulation, and consideration of a preventive such as neem oil during the heat of summer. Powdery mildew does not harm the plant; it is a cosmetic problem.