There are two types of blackberry plants, each with a different growth habit: trailing blackberry bushes (semi-erect blackberries) and erect blackberries (upright). Trailing blackberries have trouble staying upright and absolutely need a trellis. Trellising ensures the fruit lasts until harvest and isn’t destroyed by moist ground, insects, and other factors. Erect varieties of blackberry, on the other hand, do not need a trellis. However, it is still useful to have trellises even for erect varieties. A trellis will help guide growth and increase fruit yields.
Can You Grow Blackberries Without a Trellis?
Erect varieties of blackberry grow fairly well without a trellis. However, most of these varieties produce a poor fruit harvest. Trailing blackberries—the kind that needs trellising—grow more pounds of berries. So, while you can grow a few blackberries without a trellis, you’ll get far better berry production, and longevity out of your plant, with varieties that require trellis support.
- Some varieties grow okay without a trellis but don’t bear much fruit.
- The best fruit bearing blackberry bushes do require a trellis.
The issue with trailing blackberry varieties is that the weight of the fruit pulls the whole bush to the ground. Semi-erect canes will sag into the dirt once they bear fruit. This results in fruit damage and fruit rot because the canes are in contact with moist soil necessary for properly watering your blackberries.
Do Upright Blackberries Need a Trellis?
Upright blackberry varieties are one of the few fruit-bearing blackberries that don’t need a trellis. However, a simple T-shaped trellis helps upright blackberries take up less space and aids in fruit production. Simply put, you’ll get a better crop of fruit in late summer with the aid of a trellis. If you want quality fruits and delicious berries, it’s best to take the time to set up these growing aids. It takes little time and the benefits to your fruit development are enormous.
Do Thornless Blackberries Need a Trellis?
Most thornless blackberry varieties require a trellis. If your thornless blackberry bush is considered “trailing” or “semi-erect” then it needs a trellis. The canes of both these thornless varieties will trail onto the ground if not properly trellised.
- Most thornless blackberries require trellising.
- Any type of thornless blackberry that is “semi-erect” or “trailing” should be trellised.
- A trellis is not required for (but is still beneficial) for erect thornless blackberries.
If you have an erect, thornless blackberry, it’s possible to grow it without a trellis. Just remember, these rules apply to both thornless and thorny varieties of blackberry bush. If you have a semi-erect or trailing variety, you absolutely need a trellis for it.
How Do You Make a Blackberry Trellis?
If you’re worried that making a trellis is time-consuming and costly, you’re in luck because it’s easy and pretty budget-friendly. A single trellis can cost as little as $20 for the supplies and can be made in under an hour. This section will teach you how to make a simple trellis for your blackberries.
Plan Your Blackberry Rows
Plant blackberries in long rows to make trellising easy. Mark the ground where the rows will be. Use a tape measure to ensure equal spacing of at least ten feet wide. This will give the blackberries five feet in either direction for lateral growth.
Plant Your Blackberries
Prepare the soil with an organic soil conditioner. You want to make sure that your soil is fairly acidic to ensure good plant growth. This is due to the fact that berry bushes prefer a lower pH scale. Be sure to plant your blackberry shoots fairly shallowly, about one inch deeper than its nursery soil depth.
Install a Heavy Post at the End of Each Row
Use a shovel to dig a hole for your posts. This hole should be at least 2 feet deep. Once the hole is ready, insert heavy 4×4 posts to act as the main body of the trellis. The posts should be 8 feet tall before being inserted. Once they are in the 2-foot deep hole, 6 feet of the post will be exposed.
- Posts should at least 8 feet tall and be installed in 2 foot deep holes so that 6 feet of post is exposed.
- Concrete can be used to stabilize the post if need be.
You can support the post with concrete poured into the hole for stability. This is not a requirement because blackberry bushes are unlikely to pull down your post. However, it does make your trellis more weather-resistant.
Add Smaller Posts Along each Row
If you have long rows of blackberries, add a smaller post every 15 feet to allow for more support for the trellis wires. This will help reduce wire sag which will keep your blackberry canes as erect as possible. Use these metal fence posts to bolster your trellising.
String Wires Along the Posts
Training wires will help guide blackberry cane growth. String 3 wires along the posts. One 2 feet from the ground, one 4 feet, and one at 6 feet. You’ll need to use 12-gauge or 14-gauge galvanized wire that can stand up to the elements. Use pliers to wrap the wire around each post for stability. On the final posts on either end, you should use a staple gun or zip ties to secure the wire. Trim off any excess wire with bolt cutters.
- Use this weather-resistant wire to guide berry growth.
- String lines of wire at 2, 4, and 6-foot height intervals.
- Secure the wire with a staple gun or zip ties/
At this point, you’ve successfully made a simple blackberry trellis. All that remains is to get your berries to grow on it properly and maintain the trellis.
Train Your Berries to Grow on the Trellis
As your blackberries grow, make sure the canes grow onto the wires. If canes are trying to grow along the ground you can lightly tie canes to the wires with loose loops of string or twist ties. Some berry growers refer to this as a two-wire system. This means that there are the main trellis wires that the berries will eventually go on as well as training wires that guide them there as they grow.
Maintain Your Trellis
Each fall or late summer, prune your bushes. Proper pruning sessions help fruit development. Dead canes can choke growth and prevent direct sunlight from reaching developing berries. Be sure to clear excess canes to give healthy canes a chance to grow.
- Prune your blackberry bushes yearly.
- Make fixes to your trellis after you’ve pruned.
While pruning dead blackberry canes, make sure the wire isn’t loose or damaged. Even with weather-resistant materials, trellises require yearly upkeep. Make repairs annually to keep your trellis in peak condition.
Training Blackberries with a Trellis
While there are varieties of blackberries that don’t require trellising, trellises are needed for most varieties. Here’s how to trellis your blackberries:
- Plant your blackberries in long, straight rows.
- Dig a two-foot deep hole at each end of your blackberry row.
- Install 4×4 post in each of the holes at the end of your berry rows.
- Add smaller supporting stakes at 15-foot intervals along the row.
- String 3 strands of galvanized wire at different heights along the posts.
- Encourage your blackberry canes to grow on the trellis by tying new canes to the wires.
- Perform yearly upkeep on your trellis.
That’s all it takes. By following these steps, your blackberry bushes will be growing strong along a homemade trellis in no time.