mattwnz:I definitely mean cedar, we specify it on almost every job we do. (am an architect)Disrespective:mattwnz:This is not the best advice. You need to be very careful of cedar in our environment. In Europe the cedar used is very clear and free of knots and can stand up to exposure and consequent silvering much better. Here in NZ our cedar can be quite knotty which when combined with our harsh sun and often coastal environments can cause these knotts to pop out and create holes in your cladding. The knotts don't even need to pop out completely to have serious consequences to the weatherproofing of the building. An oil or paint system is definitely recommended for any cedar cladding in NZ. YMMV
You can just let it go natural,
I have never seen 'knotty' cedar being sold, as it is all imported as far as I am aware. If you are getting knotty cedar, it will be seconds, or it may not be the quality western red imported stuff. New cedar for cladding should be sold in 'clears' , and shouldn't have ANY knots in it. We have had cedar weather board unstained for decades,(no knots) as it has natural protectants in it, and looks as good as new now it has been stained. Staining doesn't really provide much extra protection, becuase if there is a knot and gap, water will still get in eventually. Painting and fiiling the holes is the only way to stop that. You maybe referring to macrocarpa, which can be knotty. Usually it is installed on a cavity with wrap behind that anyway these days. The thing is most claddings can leak to some extent anyway, that is why there has to be ways for the water to drain out. It is becuase water couldn't get out , that was a contributing factor of the whole the leaky building thing, which is why most cladding now requires a cavity to allow water to get out from behind the cladding. Anyway, the local TA will tell you what is and isn't allowed anyway when it comes to cladding.
Older cedar is better than some of the newer stuff but don't assume everything is clears.