I have a very full, vigorously growing Mandevilla in a large planter. It appears that it is becoming pot bound. The planter is large, about 16"-18" diameter. Should it be transplanted?
Certified GKH Gardening Expert
Repotting every 2 or 3 years during the winter is a good idea and keep is from becoming root bound.
A container 2 to 3 inches in diameter larger is a good idea with fresh planting medium to refresh the plant.
Here are a couple of articles.