Welcome Leah! Your newly found trellises are AWESOME!! And I think they look great against your house...perfect in fact. I think that since they look pretty sturdy, I would use some pretty good size rebar...maybe bigger than 1/2 if you can find it, then put the conduit over that and secure the trellis with some large, black zip ties. That way you can attach them to the conduit after you lean them against the house.

Hope that helps!

Don't know where you live but if they are very heavy I think I would try to get them so they will be secure while they are "on the ground' .There is 3 solid areas so 3 places to secure them from back & in 2 places on each of those 3 solid areas. Get 3 poles that won't bend & drill into each pole. Run 3 bolts through center pole, 1 on each solid area so that the thing isn't going anywhere & outer 2 poles run bolts through front to back so trellis is secured to poles,then pound rebar that will fit inside the 2 side poles a good distance so allow plenty to be in ground & rest up the poles to hold it all in place, may want to put solid metal strap across bottom solid where poles are so it is secure as possible from winds & other forces!! Someone else may have better idea. They look wonderful there & compliment your house. So you don't want them falling but would require couple of people to raise them up to get them over the rebar. Could attach as above, using 2 poles & bolting 3 places per pole & then cement the poles in the ground (disassemble so poles could dry in concrete & then reassemble ) Jan