How to Build a Blackberry Trellis: a simple way to grow thornless blackberries
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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? 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. It’s a long structure composed of posts, wire, and eyelet screws, that allows long vines to be tied onto wires. Some thornless blackberry plants sprawl over the ground if you let them. This isn’t convenient for growing them and makes the berries more likely to be taken by wildlife. Instead, you can train the vines to grow on the trellis I show you how to make below. It looks great, helps with harvesting, and also helps you manage the plants and prune blackberries in the dormant season.
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 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!
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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. 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.
- 4×4 wooden posts about 60″ long
- Two vine (or eyelet) screws for each post
- Heavy-duty garden wire
- Concrete (optional)
- Paint (optional)
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. In the newer version of this that I built at home, the posts are ten feet apart.
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 started leaning 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. 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.
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Last winter a neighbor moved out, so her thornless blackberry which had produced only a few berries was pulled out, across a sidewalk from my garden patch (in southern california). To my surprise, new sprouts came up on my side of the walkway, as well as several new places in the original area. The vines look healthy but not wanting to spend $$ on this I haven’t trellised them, only watered them. Not sure what help they need to begin bearing fruit. Should the vines be pruned in October? And how much? Have heard of blackberry leaf tea but not sure if taking leaves is okay?
Hi Maida, what a bonus! Free plants are such a gift :) Do you remember how your neighbor grew them? Were they on a trellis? The reason I ask is that there are three main types of thornless blackberry plants: erect, semi-erect, and sprawling (called dewberries). The latter two really benefit from trellising if you want to get a good yield of berries and keep the plant healthy. As for pruning full canes, you would take out any dead wood in winter. You know it’s dead because it will look brown and desiccated on the outside and inside. Berries only grow on thornless blackberry canes in the second summer of their growth, so avoid taking off canes if you’re unsure. As for spending money on trellising – you can DIY one with all kinds of scrap/free materials. Blackberry leaf tea isn’t common but the very young leaves can be dried and used for it. They taste a little bitter from the tannins in the leaves and quite earthy. Nothing like the berries, though.
Is it normal for these canes to be 8-10 feet long? Our raspberries bushes stand above our 6ft fence as well people say they have never seen such tall bushes
Hi Barry, yes, it’s normal for thornless blackberry canes to be that long. I tend to trim the ends off, as necessary, when I tie them into wires. There are upright varieties of thornless blackberry that grow similarly to raspberries – is that what you grow? The type I grow is semi-erect, so the canes grow up, then bend down once they get to about two feet tall.
I just found this website a few minutes ago. Looks awesome and I have signed up for your newsletter!!👍👍
I read through the comments/questions from other readers and now I have a question! We live in north central Indiana. My wife wants me to put the blackberry trellis running north-south about 8 feet to the east of our pole barn which is probably close to 20′ tall. Will that block to much sun and possibly give us sour tasting berrys?
Thank You for what you do!! 👍👍
Hi Jim, personally I would place blackberries in full-sun. I think your gut feeling is telling you to do the same? Any kind of shading could have an effect on how well they produce and for a perennial planting you want to make sure that it’s the best you can give!
Thank you for this information!! Looks so simple even I should be able to have blackberries very soon!!
One suggestion…. I was given this advice back in the 80s by a friend of mine who owns his own fence installation company. I have done this on numerous fencing projects over the years I have NO reason to change!😊 You mentioned putting the posts in concrete. I NEVER use concrete. Instead, my friend said to use pea gravel!
– It is A LOT cheaper
– It is less labor intensive
– pea gravel will not hold rain/ground water against the post. Water will drain away; just make sure you dig the hole deep enough and put enough gravel in the bottom of the hole for the post to sit above the water level
– concrete will eventually pull away from the post which allows water to pool against the post to cause deterioration
– if you use pea gravel, the more movement of the post that occurs, the more it tightens the grip of the pea gravel against the post; the longer the post is in the ground, the more secure it will become
Just thought I would share that thought! Hope it is useful to somebody!👍
Great tip! Thank you
Is it possible to grow one plant in a large 1/2 wine barrel?
Yes, I think so. You’ll need to keep it well-watered and mulched with compost to keep the plant healthy and productive, though.
Hiya, love this post! could you go into a little more detail how you seperate the 1 -2 year old fruit producing canes and the new canes?
Hi Bec, older canes (including second year wood) look brown and withered while new canes (first year) are green and alive. This becomes more apparent the further you are into the dormant season.
Can I plant in front of a vinyl fence or does the plant need airflow behind it?
Airflow is best, and not having an obstruction on one side will make things easier when harvesting. However, if you left at least a good 18-24 inches between the fence and where you plant, it should be okay.
A much easier way to propagate black berries is to stick the top of a primacane in the ground, cover and 3-5 weeks roots will form. Cut off from the main cane and plant. Done no hormone needed.
Thanks, I’ve been needing some ideas for trellising our wild blackberries
We have lots of wild blackberries and lots of deer and I’ve only really noticed the deer eating the leaves, not the actual blackberries, but I could be wrong.
Do you have any issues with deer eating them? We have lots of deer and everything I’ve looked up says deer like blackberries. ???
We don’t have deer here, so that’s not an issue that I have.
If you put an egg in a blender and mix with a gallon of water the deer won’t eat your plants. You have to re-apply after a few weeks or after rain.
Wondering how to incorporate a trellis with a chain link fence. Any way possible??
I’d just grow the blackberries on the chain-link fence. Simple garden twine will hold the canes in place :)
My thornless blackberries are very sour. Any suggestions.
That’s unfortunate but I’ve heard a few people complain about their thornless blackberries. I suspect that it’s either the variety you’re growing or that they do not have enough sun. Blackberries tend to have a sour flavor when they ripen in shade or in cool weather.
Hi Tanya, do you have any idea how to protect climbing berries from birds? I have thornless blackberries growing up a fence (along with other berries) and i am at a loss. Any advice would much appreciated
I don’t have issues with birds making off with my thornless blackberries and so leave them to grow without protection. I’ve collected some ideas on how to keep birds out of the garden though, and maybe one of them will help you?
This is just what I was looking for Tanya, we recently had to replace our fence which supported our BlackBerry vines. This is perfect. Thank you.
Do you tie the blackberry vines onto both of the wires? With string? Every branch? If so, what time of year?
It depends on the cane and if it needs tying to both wires. If it looks like it needs more stability where it crosses the bottom wire, then tie it in. Use garden string but loop it in a figure 8, with the wire in one loop and the cane in the other. This helps stop the wire from rubbing against the cane. Time of year: I tend to do this in the dormant period right after I cut back the old canes.
I tied my blackberries which were about three years old. It was four very small bushes. I noticed they started to die out after that. I only have one piece left. What did I do wrong?
Hard to say without seeing them and understanding how you are growing them. It could have nothing to do with the trellising of your blackberries.
Hi Tanya,
When you say paint the posts, does that mean paint the bottom of the posts?
(The part that’s going in the ground)
If yes, what type of paint would be used to stop the bottom of the post rotting in the ground?
Kind regards.
I simply painted the above-ground parts of the post to protect it from the weather. They’re not treated underground but the posts will last many years, regardless.
In one of your pictures I saw what looks like a stick or a rod with an overturned plastic bottle on top. I have seen this in other gardens. What is it for? Thanks!
It can be for three things — when the bottle moves around in the wind it creates a noise that can scare off birds. It can also help hold netting up if you drape it over (otherwise it falls down over the cane), and will save you poking your eye out if you’ve got canes sticking up and you bend down to access an area.
Hi! After building the trellis, where do you plant the blackberry bushes? By the posts or between each post?
Between is better, but next to the post is fine too.
How far apart are your posts? Are you suggesting I use the 2mm (14 gauge wire) you have noted above as the wire between posts? Thank you
What variety of Blackberry are you planting to use the trellis. Standing, trailing?
Trailing
Tanya,
Which direction does your blackberry ‘fence face?
East to West: it’s south-facing