A sun-hardened frangipani is one that has been growing in a sunny position. It’s one that can be placed or planted in a sunny position and not be damaged by the sun.
If a frangipani has been growing in a shady position and is suddenly put into a sunny position, the sun is likely to burn its leaves. The sun might also burn the frangipani wood, especially if the plant is small and the sun is hot.
Frangipanis should be exposed to the sun gradually. After a seedling or a small frangipani plant has had 2 or 3 years to grow in filtered sun or full shade, it should be moved to a position with more filtered sun and a little direct sunlight. The amount of sun for larger frangipani plants or small trees can be increased on a monthly basis.
The amount of sun for small frangipani plants can be increased each year, in winter or spring.