What Could Cause My Well-established Crossvine Plants (5 Of Them) To Up And Die?
Plants are against a cement wall; are on a drip watering system; have done fabulously for 3-4 years now (including through our long hot summers). Toward the end of August, one developed many dead parts and from there it has spread to adjacent crossvine plants. There does not appear to be any bug issue.
Certified GKH Gardening Expert
It sounds like the soil may have contracted an infection. Fungal/bacterial infections can come out of nowhere, but are usually the result of staying too wet for too long.
From here, you will want to treat with a fungicide. This article will help: https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
You may, also, want to use a handful of DOLOMITIC LIME per plant, and a teaspoon of WETTABLE SULFUR per plant. Cast this into the soil, and it will work itself in with a few waterings. This will help to take out any remaining infection, as well as condition the soil.
This article will help you with Crossvine Care: https://www.gardeningknowhow.com/ornamental/vines/crossvine/bignonia-crossvine-care.htm