Q.plumbago is turning brown and appears to be dying
My 3 year old plumbago is turning brown and appears to be dying…any suggestions? This is the first time I have had a problem with it.
It could be environmental or fungal issue.
Has it been excessively damp or rainy? Or hot, dry?
If it is dry I would add some water to the shrub. Mulching can help with moisture retention. 2 to 3 inches of hardwood mulch.
If the plant is sitting in soggy soil it can lead to root rot.
You may want to treat the plant with Neem OIl. This works as both an insecticide and fungicide.
Here are some links for you.
https://www.gardeningknowhow.com/ornamental/shrubs/plumbago/growing-plumbago-plants.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm