What is the best tropical plants/trees to use in sheltered sunny garden, taking into account our cold frosty winters?
The true Tropics have no frosts.
However, if you are thinking about a ‘tropical’ effect border there are some plants that can survive outdoors in winter in mild areas, such as Dublin where you are.
These could include Chusan palm, fatsia, tree fern, arum lily and cordyline and even a couple of those are borderline.
The main show would be added to in summer by plants overwintered under cover or covered outdoors, such as Japanese banana, canna lily and elephants ear. Other colourful plants coul dbe used especially dahlias, ginger lilies, zinnias and amaranthus.