Tony: That was carribbean-flavored dry Brit humor Brian will understand... unless he has been in Japan too long.
Lee: I'm going to let it weather. I could not find anyone who could assure that nothing harmful would leach out of any particular paint or stain, so the useful life of the wood exposed to our hot, humid climate will be running its natural course. Many years ago I had a western cedar shadehouse for bromeliads, orchids, etc. After 7 years it was still standing, but I tore it down to make way for a structure better designed for my use. So, I'm figuring I will get at least 7 years out of this structure without painting, and probably more. You will recall that I did use a water sealant on the uprights since no risk of water dripping from them into the pond and they will be more exposed to water from irrigation, so I have more of concern about them. The structure will probably be two-toned in 6 months due to the water sealant retarding the natural weathering process on the uprights only. In a couple of years I expect all the wood will be shades of gray.