The best DIY trellis isn't the prettiest one, it's the one matched to your plant's growth habit. A copper pipe grid works brilliantly for jasmine and fails for grapes. A cedar lattice holds star jasmine beautifully but drowns a young sweet pea. Pick the frame for year two, not week one.
https://www.omnihomeideas.com/patio-lawn-garden/diy-trellis-ideas/
