How to Build a Blackberry Trellis: a simple way to grow thornless blackberries

Wood, wire, and eyelet screws are all you need to build a simple blackberry trellis. This is an inexpensive way to grow thornless blackberries in the vegetable garden. There’s a video showing how I built mine at the end of this piece.

I’ve had some people ask why would you bother growing blackberries when you can pick them wild. There are two reasons really. First of all, no thorns, and secondly the berries on the cultivated bushes are bigger and sweeter than those in the wild. Did I mention that they’re not invasive either? Unlike wild brambles, they don’t grow where they’re not supposed to. However, their long trailing canes do need support which is why you’ll need to build a trellis for them. These are my simple instructions for how to build a blackberry trellis.

Love Blackberries?

• How to make Simple Blackberry Gin
• Autumn Foraging Guide: 6 Easy to Identify Wild Foods
• How to Make Fruit, Flower, and Vegetable Wines

Build a Blackberry Trellis in Winter

If you’re ordering plants online, your blackberry bushes can arrive in the winter as dormant and bare-root plants. Before you have them in hand you should set aside an afternoon to install a simple blackberry trellis. It will give the canes something to grow on, make harvesting the berries easier, and can create a nice boundary fence. I have mine running along the bottom of my veggie patch.

Once you have the trellis built, you can plant a bare root berry bush near each post. As the canes grow, you can tie them onto the wires with string. Thornless blackberries fruit on second-year wood and then those canes brown and wither after summer ends. They’ll need to be pruned over the winter and removed from the wires. New growth is then tied on for the next year’s harvest.

If you purchase thornless blackberry plants growing in pots, you can plant them in the ground any time of the year, providing that the ground is not frozen. That means that you could build a blackberry trellis at any time of the year too!

What You’ll Need to Build a Blackberry Trellis

To create your own trellis you’ll need just a few DIY materials that you can get from any hardware store. If you have the posts already, you can just order the other items on Amazon if you’d like. I’ve left the links below.

• 4×4 wooden posts about 60″ long
• Two Vine (or eyelet) screws for each post
• Heavy-duty garden wire

Painting the wood is optional but it may extend the life of the posts if you take the time to do so. The eyelet screws you use should be suitable for outdoor use and have an eye big enough for two wires to fit through. If you don’t have them on hand and want to save money, you can use ordinary screws and wrap the wire around them. I go over this in the video you’ll find at the bottom of this piece.

Adding Wire & Screws as Vine Supports

You might ask what the benefits of eyelet/vine screws are vs ordinary screws. They keep the wire a distance away from the wooden post creating more growing space for the canes between each. If you use screws then the canes will be tied up against the post and could rub against it in windy weather. It’s not a deal-breaker though and you can choose to use either.

As for the wire, I’d recommend that you use 2mm (14 gauge) garden wire or thicker. If you use thinner wire then you risk the wire sagging or breaking when the canes are in full leaf, flower, and berry. 14 gauge is what I’m using and it’s easy to pull tight and to twist the ends. Thicker wire is probably better if you have more distance between posts than I do but it can be a little harder to work with.

Build the Blackberry Trellis

To construct the trellis, measure out the length that you’re building the entire structure. Each blackberry bush will need at least six feet on either side to stretch out its canes. That’s why I have my posts spaced out about seven feet apart. Any more than this and I think the wires would sag too much.

Sink each post two feet in the ground and firm it in really well. If you want really solid posts then you might want to consider concreting them in. I’ll be doing this over the winter since my posts have moved quite a bit this summer. The two posts on either end of the trellis have pulled inwards, causing the wire to sag in some places.

When all the posts are in, screw in the eyelets. Two go in each post and they should all be placed on the same side of the posts. My bottom eyelet is 12 inches off the ground and the top one is 3 inches from the top.

Attaching the Wire

Each stretch of wire between posts on mine is a separate piece. There’s a six-inch overlap with the screw head so that I can pass the wire through and twist it back on itself.

You could string a long length all the way down your trellis but make sure that you wrap it around each screw all the way down. Forget this step and that wire will likely sag. The reason I didn’t do it this way was that the wire was too cumbersome to wrap around the eyelet screws as I went along. If you use ordinary screws it will be much easier though.

Free Blackberry Bushes

I need to pass on a tip if you’re like me and like to get plants for free. If you have a friend who already grows thornless blackberry bushes, it’s EASY to create new plants from it. From late spring to mid-summer, take 12-18″ cuttings of fresh new growth and propagate them like this. By the next spring, you’ll have loads of blackberry bushes to plant out without having to hand over cash for them.

Growing Thornless Blackberries

Once the trellis is built and the blackberries planted, you can look forward to many years of berry harvests. The blackberries I grow don’t intrude into the ground too much so aren’t competing with my other garden veg. They’re also growing in a space that probably wouldn’t be used, creates a bit of a windbreak, and give my plot a bit of privacy. Best of all, I do a little maintenance and mulching and they produce countless juicy blackberries. I do love an easy harvest.

• 7 Ways to Build Bean Supports
• Build this DIY Herb Spiral
• DIY Pallet Cucumber Trellis (no tools required)