Some or the leaves are turning dark. Is this normal? I just planted it this year.
Certified GKH Gardening Expert
On some varieties, such as vining forsythia, it is normal for the foliage to turn dark. On the other hand, if it isn't a variety that normally turns dark, this can be a sign of slight over-fertilization. Now if you haven't fed the plant or changed its soil recently, then I would be inclined to believe that it is a pH issue. For controlling pH in soil, and just in general for the health of the soil zone, Dolomitic lime is a good thing to keep around. Just add it once or twice per year, and it will help. Here are a fews articles that will help: https://www.gardeningknowhow.com/ornamental/shrubs/forsythia/