My mandevilla is approx. 5 years old. It is kept in the basement over winter and brought out to the patio in spring. I would like to transplant it to a larger pot, but the tubers now fill the pot. Should these be trimmed or left alone?
If the roots are protruding from the container, it is likely time to repot.
Choose a container that is slightly larger and wider then the existing pot.
Mature pots can generally use a 12 to 20 inch pot. You generally move up 2 inches in pot size as the plant grows.
Make sure it has adequate drainage and use a light fast draining potting mix.
Pre mixed potting soil that is made for cactus is a good choice.
Do not trim any roots or tubers.
The plant should have about an inch or so of new space all around the root ball.
Do not plant in too large a container, as this can lead to over watering and root rot.