Do I need to tie branches to the trellis or does it wrap by itself?
Certified GKH Gardening Expert
Wisteria will attach itself to anything it can wrap around and will reach for anything that it might be able to wrap around.
What kind of support depends on what you plant on letting the wisteria do. If you plan on pruning yearly and heavily, you do not need as large a support. But, regardless of what you plan on doing, the support must be sturdy. Mature wisteria are very strong and can literally rip apart a flimsy trellis.