Q.My Mandevilla just died
We did everything we thought we were suppose to do but almost overnight it just started dying. It turned brown, all the foliage fell off. We cut all the dead areas off but it still has not recovered. Please help it is my favorite vine and it was so beautiful and full of blooms.
First question would be how old was the plant. If you planted it within the last few months, check the basics in this article: https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant.htm
If it was an older plant, there is a bacterial disease that can kill them, called southern wilt. You should plant a different plant in its place, because the bacteria remain in the soil. If you want to be sure, you can have the soil tested. Check with the local Extension Service for more information: https://www.gardeningknowhow.com/extension-search/