Q.Why is my potted Mandevilla dying from bottom up?
Plant has full Sun, potting soil plus African violet soil, great drainage, periodic MiracleGro water-mixed fertilizer, and a metal and plastic trellis. Recent weather dry, then rain. No bugs seen on plant or in soil.
These are very sensitive to full sun. This needs to be in a shaded area, or dappled sunlight. This is the reason that it is dying. This article will help: https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant.htm