I just recently observed some yellowing and brown leaves on my Sweet Autumn. This grows quite tall and thick on multiple trellis. Upon further investigation, the interior, hidden by the profuse leaves is turning brown. This is quite a favorite of mine and quite a show stopper in my yard, I really am worried that this browning, which is not obvious when you first look at it will spread and ruin my display as well as future blooms. It has never done this before. We did get an enormous amount of rain this year, which is affecting a lot of my plants, but it is in a well drained area and it is just (at least for now) the leaves in the interior. It is still growing, expanding to an additional trellis, which was added for it to spread onto. Just to give you an idea on the thickness of this clematis, if I reach in to touch the trellis it is on, my arm will be buried up to my elbow in clematis. Any ideas?