E. sandwicensis should not be watered to the point where it is no longer a deciduous plant. When a plant dies the stems tend to shrivel up and the green tissue directly under the outer bark of the stems is not longer green. It is good that you are not giving it much water. But I notice that dryland plants pllanted in pots still need to be watered Because the pot can dry up entirely. Since wiliwili is a tree the roots go deep into the soil where water may be present (even if in small amounts). This is from my experience and observation. When watering I moniter my plants. I have a wiliwili I bought in a 3 gallon pot 1 year and 9 months ago and it is still in the pot. It is starting to grow back its leaves (at this time the trees in makua valley have not leaves and are flowering). I have probably watered it more than it has needed before. But not I allow soil to dry out nearly completely and moniter the appearance of stems and leaves. Although overwatering is possible, with wiliwili it is not necessary to give it only the water it needs.