I have a very large and nice white trellis with a Thunbergia alata "Mary Lou Herd" currently growing on it. I did not expect this pattern of growth but it "clumped" into one area in the middle and is growing out from that. It looks very nice but this was luck not design. Are there other vines that I could grow on the other side of the trellis that might complement this? It can be a variegated leaf or interesting leaf shape; it does not need to flower, and this trellis is largely in the shade until the top section. I want evergreen plants only.