Blackberries and blackberry hybrids, such as thornless blackberries, loganberries, boysenberries, youngberries, taybberries, silvanberries, marionberries and lawtonberries all belong to the genus Rubus, along with raspberries.
Unlike raspberries which have vertical growing canes, blackberries and their hybrids have long trailing horizontal canes, which are usually supported on trellises, or horizontal wires attached between fence posts.
How to Prune Blackberries and Their Hybrids
Brambleberries such as blackberries and their hybrids produce new primocanes which grow in the first year, and then turn into floricanes in the second year that flower and fruit. After the floricanes have fruited, they won’t bear any more fruit, and need to be removed.
- Fruit is produced in summer, usually during Dec-Jan in the southern hemisphere, depending on the variety. Canes which have fruited are cut to ground in autumn.
- In early spring, fruiting canes are tied to or woven around trellis wires.
- Any laterals (side branches growing from the main canes) are shortened to about 45cm (18”).
- Maintain 6 to 8 canes per clump.
Training and Supporting Blackberries
The long horizontal canes of blackberries and their hybrids need to be supported on a trellis, and must be kept off the ground. If canes rest on the ground, they will root into the soil, and a new plant will emerge with its own roots and canes from that point!
Using a trellis or some kind of support structure makes pruning much easier, because it provides a means of separating the new primocanes which are too young to fruit from the year-older floricanes which are productive.
How to Build a Trellis Support for Blackberries
- Use posts 2.4m (8’) long, driven 60cm (2’) deep into the ground, leaving post 1.8m (6’) above ground.
- Use galvanised wire galvanised wire, 2.0mm or 12 gauge in thickness. Attach four wires positioned at heights of 90, 120, 150 and 180cm (3, 4, 5 and 6’).
The diagram below shows the wire spacing for a tall blackberry trellis.
It’s also possible to build a lower blackberry trellis using shorter posts and only three wires, as shown below.
A trellis can also be constructed by fastening galvanised wire between wooden fence posts at the same spacing.
Another possibility is to fasten wire mesh to a fence for use as a support. Use a mesh with 10cm (4”) wide holes, as it’s easier to pass your hands through and work from both sides.
In smaller spaces, garden arches are an excellent solution, as they provide a very large growing area, while occupying very little space themselves.
Traditional three different training methods are used to support blackberries and their hybrids, these are the Rope, Fan and Weave training methods. There’s also a newer and very efficient method, which I prefer, which we’ll also explain in the next section.
Blackberry Training Method – Rope
This is the simplest training method, but it’s not the most productive, as canes are bunched very close together, and leaves can shade each other out.
With this system, new canes (primocanes) are tied vertically or wrapped onto the lower wire.
Even though this method takes the least work, it requires a lot more handling of the canes, so gloves required to avoid the thorns!
Blackberry Training Method – Fan
This training method provides high yields, but is labour intensive, and is recommended for less vigorous varieties (such as the compact and thornless varieties).
With this system, fruiting canes are tied to both sides of the trellis in an arching fan shape, and new canes (primocanes) are trained vertically, and then tied at the top wire.
After fruiting, the old canes are cut to ground, and the vertically tied new canes are spread and tied to each side to take their place.
Blackberry Training Method – Weave
This training method provides the highest yields, but is the most labour intensive!
With this system, fruiting canes are woven to both sides of the trellis, and new canes (primocanes) are trained vertically, and then tied at the top wire.
After fruiting, the old canes are cut to ground, and the vertically tied new canes and woven and tied to each side to take their place.
Blackberry Training Method – Straight Run
This more modern method of training blackberries and their hybrids is the simplest of all, and it works very well.
It doesn’t make the most efficient use of space though, as the canes are not folded or bent, so there canes are much shorter than on the previous training methods, and would therefore yield less on the same sized trellis frame.
Where this method is ideal is when large support areas are available, such as on fences, where long canes can be supported their whole length without having to fold, bend or weave them. This is also the system used when growing over arches, but the canes are only run from one side of the arch, reaching over to the other end.
Blackberry Training Method – Three Wire Wrap
Another, highly efficient and productive, modern method for training blackberries and their hybrids only requires a three wire trellis.
With a clump of six canes, three canes are bunched together and loosely woven around two top wires one each side of the trellis.
New canes (primocanes) are woven around lower wire, to separate them from the fruiting canes on the top two wires.
Tip: Loosely tie the older fruiting canes (floricanes) together near the base. After they have finished fruiting, cut the canes tied in a bunch to the ground. Then, unwind the younger primocanes from the lower wire, and wind then around the top wires to take their place
How to Protect Berries from Bird and Animal Pests
Berries are very tasty and nutritious, and are loved by most people.There are birds and other animals that enjoy them equally, so it may be necessary to protect blackberries and their hybrids from these pests.
It’s best to use fine insect exclusion netting to protect the berries after flowering. This fine woven netting has a 2mm mesh, which will also keep most insect pests out too.
The main advantage of such a fine mesh netting is that the ends of the canes can’t grow through the holes and get tangled in the netting.
This netting also doesn’t get caught on the thorns of the berries, making it easy to put on and take off as needed.
An easy way to cover berries is to drape the netting over both sides of the trellis. On fences, the netting can be attached to the top wire or to the wire mesh using clothes pegs.
Berries lend themselves well to vertical gardening, taking very little space on the ground, while covering large, open vertical spaces.
Make sure that the location in the garden used for growing blackberries and their hybrids is not exposed to wind and hot afternoon sun. Ideal locations receive morning and midday sun, with afternoon dappled sun or shade.