regarding a Red Mandevilla

Question

I have my plant in a contaier in the garden facing east and getting the full sun throughout the morning (this year has been dreadful though). This is the 4th year I have had a Mandevilla plant. Each year I have purchased one from a local supplier. This year the flower develops but will not open fully. It remains in an open bud formation. What can I do to encourage the flowers to open fully – could it be a genetic fault with the plant?

Answer 1

Here is a link with great information.
Soil, feeding the plant and the correct light conditions are very important.

https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant.htm