There are two main uses of the Crown Flower tree. First, as a member of the milkweed family, it is a host plant for the Monarch butterfly. It gives me great pleasure to watch all the butterflies in the garden and to know that I am helping to support them. Around December the butterflies show up in large numbers to lay their eggs on the underside of the Crown Flower leaves. These hatch into tiny caterpillars who will munch and munch until they are big and fat and a couple of inches long. Then they will climb down the tree and go off looking for a fence, or another shrub, or the side of the house to attach to. They hang upside down in a J shape and turn into a beautiful green chrysalis trimmed with gold.. After about 14 days they will hatch into Monarch butterflies. I enjoy watching them and so do all the grandchildren and the neighbors kids
The only down side to all this process of nature going on is that the caterpillars will chew down every leaf and the tree will look very naked and straggly for a month or so but it will revive just fine. I usually trim the tree at this time when the caterpillars have done with the leaves and the new growth has not yet come out. Because of the sad appearance of the tree for those short few months I decided to grown my present Crown Flower tree at the back of our garden instead of in the front yard. One visitor horrified me by suggesting I should be using some sort of insecticide on the caterpillars!
When picking the flowers to make leis, I always be very careful about wearing a hat so I do not get the trees white sap dripped in my eyes. The sap can cause temporary blindness. I noticed in Thailand that all the Crown Flower trees there were kept trimmed to about waist height. It would make for easier picking but also much safer for the eyes. The picked flowers then need to be soaked in cool water for a few hours to get the white sap off them as well as giving them a last perk up drink. Crown Flowers are a very long lasting in the fridge so are good for leis that are being sent to the mainland.
PS......added in 2013 after a trip to Israel. While there, I actually saw a Crown Flower in fruit and so I am adding a few pictures as we never see them in fruit in Hawaii. I guess we do not have the pollinator. The Crown Flower in the Israel was just slightly different in flower, it was the same as the one I saw in Dubai, but still a very close cousin. The green seed pods are huge like the size of an orange but when you pick them they are as light as a balloon. I stomped on one and it popped loudly and inside was just a small core. On the tree were a few older shriveled looking pods...and then a cluster of seed ....like little dandelion seeds with umbrella shaped fluff on them. The fruited laden tree was quite a different aspect of the plant for me to see. It was growing wild near the entrance to Masada which is a very dry, hot area. Here are few of my photos of it.