I did this graft last year after about 4 months of learning grafting. This one did not go well. As you can see, there is actually a hole through the graft area under the scion (the top part) and above the root stock (the bottom part) – an actual tunnel through the graft!
But here’s the amazing thing…it lived! Apparently the graft took enough on the sides to keep the scion alive and it continues to grow (a year later).
PLUMERIAS ARE RESILIENT!