Balcony Trellis Without Harming Walls

We wanted to build a trellis on the balcony, to grow climbing roses on the divider between us and the neighbor's balcony. But the house is new and we can't do anything to the walls, and the thing obviously needs to be stable so nothing breaks or falls over.

Here's how we built this stable bespoke trellis, without damaging the walls.

We got two IKEA ASKHOLMEN flower boxes.

I found a plastic bag from a store that fit perfectly in the box. I trimmed it down to the height of the box and stapled it in place, together with some burlap to hide the print on the bag.

Remember to cut holes in the plastic for drainage!

Now we can plant directly into the flower box, without pots. IKEA Hack!

Collected some poles in the lot by the heating plant. Remember to not cut down living trees, or break other laws..

We cut the poles to height and nailed floor protectors in the bottom of them. Then screwed them into place with metal strips.

Now, we cut the horizontal poles to size and temporarily tied them together with string. When happy, we screwed them together (drill first!).

On the top bar, we took a spare piece of wood with a floor protector nailed into it, and screwed it in with a longer screw.

I thought a long time about how to secure the trellis without harming the walls. I tried a few things, but came up with this:

I bolted two 90° metal brackets together, and covered it with self-adhesive felt on the inside. I also sprayed it white, to look better. It actually fit much better than I had anticipated!

I tied the brackets to the trellis with string. It's very stable, and no harm to the house! Yay!