The main reason to graft Plumeria cuttings are:
Grafted cuttings can have a fully functional root system within 10-14 days. Rooting a cutting can take 4-8 weeks for new roots to form.
A grafted plant allows us to take a cutting and place it onto an established root system.
The growth of a grafted plant will be at minimum of one-year ahead of a rooted cutting plant.
You can leave Inflorescence on grafted cuttings. An Inflorescence left on newly rooting cuttings will slow down the development of the roots.
A grafted cutting will bloom sooner and produce more blooms than a newly rooted cutting.
A grafted bloom will be a normal flower. Newly rooted cuttings will often produce an inferior flower, called a root bloom.
Rare and hard to find Plumeria are more likely to be difficult to root from a cutting.
A single Plumeria tree can have multiple varieties grafted onto it forming a multi variety tree.