Do Metal Trellises Burn Plants?


Iron Trellis with Natural Leaf Design

As a gardener who loves my flower garden, I’m careful to put sun-loving plants in the sun and shade-loving plants in the shade. The last thing you want is to accidentally kill your plants by putting them in the wrong place. So just like you, I wondered, is a metal trellis safe for my plants?

There are so many wonderful creepers, which are vines that grow along the ground, a wall, or any type of frame you train them to. A trellis is usually a flat, decorative plane that leans against a wall and helps you train your vines in a certain place.

You can also purchase an obelisk trellis. This is a stand-alone three-dimensional trellis that stands in a corner of your garden or as a centerpiece, also for training a vine in a decorative way.

Stand-alone Trellis

Another style of stand-alone trellis is a hinged, room divider style. Metal trellises are great for this style because they are less likely to blow down with strong winds.

Trellises are made of wood, vinyl, plastic, or metal. You would think that if a trellis can be made of metal that it would be safe, right? But that’s not always true.

Copper, aluminum, wrought iron, and cast iron are all used to make lovely and sturdy trellises in a variety of styles. They are strong, attractive, and affordable. Who wouldn’t want a heart-patterned trellis to class up their garden wall?

The problem is that metal conducts heat. A metal trellis will absorb a lot of heat on a hot summer day, and then it will share that heat, radiating it into the surrounding plants. Metal trellises may burn your plants on a hot day, but there are things you can do to prevent this.

The Best Place for a Metal Trellis

The best place for a metal trellis is in the shade, so be sure to plant vines that love the shade when you’re using a metal trellis. Luckily, most walls have a roof overhang that provides some shade throughout the day.

Anything that needs a lot of sunshine likely won’t be as happy attached to metal and permanently stuck in the shade. And we all want our plants to be happy.

Some plants surprise you and can thrive along metal lattices. I’ve definitely seen many chain-link fences covered in happy greenery. However, in my own experience, it isn’t easy to start tender baby plants along a metal trellis or lattice in hot weather.

Wire Trellis, Tender Young Plant

I thought it would be a great thing to grow grape vines up our chain-link fence in the front yard. I am not a huge fan of chain-link fences but it was here when we moved in and we can’t afford a whole new fence right now.

So I bought several baby grape vines of different varieties and optimistically planted them at the base of each fence panel. To my chagrin, they responded poorly to the openness of the area. They had no protection from the cold of late frosts or the intense heat of spring in Central Utah.

Next time I try this, I’m going to start my vines inside and only bring them outside once they are established and the weather is temperate for at least a week in the forecast. Remember that metal intensifies both the hot and the cold in the air.

It might be a good idea to take a drive around the neighborhood and see which types of plants are thriving along the fences in your area. If your heart is set on putting your metal trellis in a sunny spot, it might be possible with the right type of plant. It really depends on the weather conditions in your area.

You can also paint your metal trellis white. Podster from East Texas wrote on Dave’s Garden forum that people who placed thermometers on their metal trellises were quite shocked at the high temperatures their plants were experiencing in the summer. After painting the trellises white, the temperatures recorded were much lower and safer for the plants.

White Trellis

Since white tends to be a popular color in gardens anyway, this is an easy and attractive fix for your hot metal trellis problem.

The Right Kind of Vine for a Metal Trellis

Another thing to keep in mind when planting on a metal trellis is that not all vining plants will actually cling to metal, so it will take more work to wrap these around and train them up a metal trellis.

You may also need to add levels of wire if your metal trellis has sections that are too far apart for the vine you’ve planted to reach between.

Morning Glory on a Wire Trellis

Many plants do grow up a trellis by twining around naturally, like the ever-present Morning Glory, which many people consider a weed. Make sure when planting on a metal trellis that you are planting the right kind of twining vine. Say that five times fast.

But other types of vines climb by attaching themselves to a wall either with clinging tendrils or aerial roots. These are happy climbing up stucco, stone, and wood where they can sink their teeth in, so to speak. They will not be happy on a metal trellis.

Is Rust a Worry For a Metal Trellis?

Rusty Trellis

Many people also wonder if a metal trellis will eventually rust and if rust will damage their plants. The answer is, it shouldn’t. Most commercially sold metal trellises are powder-coated and marketed as weather-resistant and rust-resistant.

If you made your own metal trellis, this might be more of a concern, but even then it’s not likely to affect the plants. Even if the rust were in a metal planter down by the roots, the type of oxidized iron in rust isn’t the type of iron plant roots can absorb because it isn’t water soluble.

However, rust will eventually destroy the metal trellis, so clean and spray your metal trellis with a rust protectant you can get at Amazon or any home improvement or hardware store. Make sure you aren’t leaving your metal trellis under a roof gutter or drain where it will constantly be wet.

Rust fungus on a leaf

(There is also a group of fungal plant diseases called rust, not related to metal. These diseases have a rust-like effect on plants, eating away at them in spots. It propagates by spores so a good fungicide can treat it. For more info, check out this HGTV article on plant rusts.)

The Timeless Appeal of a Metal Trellis

Heart-shaped Wrought Iron Design

With all these things to consider, why do people make, sell, and buy metal trellises?

Here are a few of the benefits of a metal trellis vs. a wooden trellis:

  • Metal trellises are sturdy. They stand up against wind much better than flimsy wooden trellises put together with staples.
  • Metal trellises have stamina. They don’t rot in the rain, especially when properly prepared with rust protectant. As such, they’re more likely to survive many seasons, whereas a wooden trellis will need to be replaced sooner.
  • Metal trellises can have fun patterns. A wooden trellis with a heart pattern? That sounds expensive and unstable. Metal is more versatile because it can be shaped into elaborate decorative styles without forsaking structural integrity.
  • Metal trellises fit a minimalist vibe. Many people are looking for a garden style that fits their minimalist home decor. Metal trellises have a no-fuss, modern look that fits a variety of personal styles, including minimalism and industrial chic.

Long story short, metal trellises are an affordable and beautiful way to spruce up your garden with some creeping vines. Whether you’re looking to add more greenery or a wall of blooms to your scene, a sturdy, attractive trellis is a great option.

With these tips and considerations you are ready to rock the metal trellis in your garden. Happy gardening!

Katrina Lantz

Katrina Lantz studies neuroscience at BYU. She is a curriculum developer at Ensign Peak Academy. She also writes under the pen name K.L. Lantz. Her published books include middle grade fiction: Drats, Foiled Again! and Bombs Away! and adult Christian inspiration: The Healing Bucket.

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