I have trained clematis to grow up all my mature tree in my yard - several maple, an ash, an elm, and a cherry tree as well- I cut and wrapped chicken wire and stapled it to the side of the tree. the wire rusts to the color of the bark after one season. I dug out a good hole much larger than needed next to the trunk where I was to plant my vine. I filled with high quality manure/compost and top soil and packed tight. I water them with the hose when I am doing the normal rounds in the yard and I have "bricked" a small boarder around their base to help hold some water at their roots. I also leave little "presents" for them of dried out/old dog droppings maybe once or twice a year near them to leach some natural nitrogen for them - they seem to love it and always give me a nice bright green burst of growth when they get their gifts and a good rain :-) I do admit on the oldest maples it was hard at first because the trunk runs outward and soil was shallow - but the brick border helped build enough base for them to get established. good luck - nothing prettier than a flowering trunk on a beautiful tree

I grow Etoile Violette up a redbud, Venosa Violacea through a styrax, and Alionushka up a japanese maple. Just realize that any clematis growing at the base of the tree is going to need extra nutrients and moisture since it will be competing with the tree for both. Also consider the age of the tree and how big the trunk may get evenutally to help determine how far away from the tree to plant the clematis. Even if you have to plant away from the base to allow for the tree to grow, you can lead the clematis vines into the lower tree branches with a cane or long pole. If it were me, I would allow the one on the trellis to grow into the tree and not prune it out. One thing that I have learned is that white colored clematis or other pale colored ones show up best growing through trees and shrubs unless of course the tree or shrub has leaves that are variegated.

Species clematis, like SAC, are often large and vigorous vines and can grow into trees relatively easily. In my area you see C. armandii, C. montana, tangutica and SAC growing well into trees, simply because they ARE so big and vigorous. And many type 3 clems will work almost as well. Tangutica and SAC are hard prune vines and yes, the vines DO get tangled with the tree branches, but are not overly difficult to remove at pruning time. Be sure to do your pruning before the tree is budded out or you can possible damage the new growth. And I would take pains to match the tree with the vine so that the tree is large enough and hardy enough to stand up to a mature vine. And that will differ with the type of clem you select. I have never had the need to use a support system (other than the tree) when doing this but it depends on the clem and how old it is when planted. Some temporary caging or supporting may be necessary but once established in the tree, this is no longer necessary. You might also want to know that SAC, Clematis terniflora (or incorrectly, C. paniculata), is considered an invasive species in a large part of the country. You might want to check with your state's invasive plants council before planting

They do not grab onto wood lattice panels well at all. I had hubby build them all over my yard before I found this out.....I have had trouble with chicken wire too. They do grab on to rebar, wire fencing, cattle panels, twine, wire obelisks....I have just been to a big open garden where they used the wire mesh grids for reinforcing concrete (4 x 8 $7.50 ea at Home Depot) and rebar to build many structures for Clemmies. Some free standing, some up against fences, some leading them into trees. They blend in to the scenery. They have used them for years. I've been to the garden many times but finally the man who built all the structures was there to talk to. Cattle panels found at Tractor/Livestock supply stores are heavier, don't cut as easily but make great archways you can walk through for under $25.00. You can make a teepee out of rebar and a hose clamp too. I've seen rebar "ladders" welded together too with decades old Clemmies on them. Reinforcing mesh wrapped around free standing 4 x 4's at another garden. There are wire trellises you can buy that are curved to cover up downspouts or lamp posts but the wire grids are much cheaper.