How to build trellis for climbing roses on limestone wall?

[diy_abhi]

Hi everyone,

I’m looking for some guidance on how to install a trellis system in my backyard.

I have a limestone retaining wall that is 15 metres wide and 1800 mm (1.8 m) tall, with a Colorbond fence installed above it. I want to create a support structure on this wall to grow climbing roses, and potentially other climbers like star jasmine later on.

I’m considering using metal mesh or trellis panels, but my main concern is around how best to mount them onto the limestone without causing damage or compromising the strength of the wall. I understand that limestone can be prone to crumbling if drilled incorrectly.

Ideally, I’m looking for a budget-friendly, long-lasting, and weather-resistant solution that gives enough support for heavy climbers like roses.

Some specific questions I have:

What is the safest and most effective way to attach a trellis or mesh to a limestone wall?

Would it be better to mount wooden battens or spacer blocks to the wall first, and then attach the mesh to that? (Really NOT looking to pursue this option)

 

Are there any product recommendations (available at Bunnings) for materials like mesh panels, wall anchors, screws, or spacers that would suit this kind of project?

Would I be better off building a freestanding frame just in front of the wall instead?

Appreciate any suggestions, examples, or photos if you’ve done something similar!

Thanks in advance.

[JacobZ]

Hi @diy_abhi,

A warm welcome to the Bunnings Workshop community, it is fantastic to have you with us.

While you are correct that limestone can be prone to crumbling, it is very unlikely you are going to compromise the strength of the wall by adding a few relatively small anchors to your wall, and you can avoid issues with the right drilling technique and some practice.

You'll want to use a rotary hammer drill with the hammer function switched off. The hammer function causes rapid back-and-forth impacts that will cause fractures in the limestone. This is essential when drilling harder substances such as brick or concrete, but in limestone, it can cause unwanted fractures around the hole. I'd suggest you drill a test hole in an inconspicuous spot so you can get the technique down and be more confident with the rest of the drilling.

You won't want to use heavier expansion anchors like DynaBolts or AnkaScrews which can cause fracturing around the hole, but you will be fine to use Ramset 8 x 50mm Blue Wall Plugs with stainless steel screws. They will still hold strong, but without the level of expansion force that a larger anchor can create. 

You won't need to use battens, but to allow your plants to climb, they will need to be able to wrap around the back of your trellis or mesh. You can use something like these Surface Gard 22mm Black Round Rubber Bumpers or washers under each screw to hold the structure slightly off the face of the wall.

You could use these Lattice Makers 1800 x 900mm Treated Pine Lattice, or these RapidMesh 900 x 1200mm 50 x 50mm Silver Wire Mesh Panels with Jack Mesh Panel Fix Clips to mount them.

Another option is to create a wire structure like @Gwandalan_Tales did for their Star Jasmine fence screening using wire project.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob 

[diy_abhi]

Hi @JacobZ 

thank you so much for the detailed advice — it’s very helpful.

I just had two follow-up questions:

1. Drill Type: I currently have a regular (non-hammer) drill at home. Do I absolutely need a rotary hammer drill for this, or will my regular drill work if I use the right masonry drill bits? I’m happy to buy specific drill bits if that helps avoid damage to the limestone blocks.

2. Trellis Gap for Climbers: I’m planning to grow both climbing roses and star jasmine. Would the small gap provided by washers or rubber bumpers (around 1–2 cm) be sufficient for these plants to climb and wrap around the mesh? Or would you recommend any other alternatives. 

Thanks again — really appreciate the guidance. I will update you with the end results.

Cheers

[EricL]

Hello @diy_abhi 

Yes, you can use an ordinary drill to drill into limestone. This is on the condition that it is at least an 18V drill and not a 12V which does not have enough power. I suggest getting the best possible drill bit your budget can afford from Kango, Diablo or Sutton. Don't go for midrange drill bits as they will not last very long. You'll need to change your drilling technique and move the drill in a back-and-forth motion to mimic the hammer function. 

Limestone is not as hard as regular stone or masonry and is actually soft, but since you are using a regular drill, it will take you more time to drill the hole. My best advice is to make sure that the drill bit does not overheat, give it time to cool down before you continue. Overheating the drill bit will ruin the tips hardness and will become blunt. How can you tell? The tip becomes very black, and the body starts to have colours like the rainbow on the steel surface. 

If you can go for the 2cm gap that would be much better for both the climbing roses and the star jasmine. The rubber bumpers that Jacob suggested would be the best material to use for your project.

If you need further assistance, please let us know.

Eric