Berries do not necessarily have to grow on trellises, but training them to grow on one allows for a much larger fruit yield and less work. Plants get more sunlight and produce more berries, while picking them is easier than if they were lying on the ground. Berries that benefit from trellises are raspberries, blueberries, blackberries or any berry growing on an upright or trailing stem.
Home gardeners are able to use the single-post method when small quantities of canes are involved. Make a single-post trellis by sinking a post securely into the ground 5 feet above ground level. Gather canes and tie to the post in tepee fashion.
A two-wire trellis is the most common type for berries, according to North Carolina State University. Sink 9-foot-long and no less than 3-inch-diameter posts 2 feet deep in the soil, 20 to 24 feet apart. Between the posts, staple 14 gauge wire 3 feet from the ground and 12 gauge wire at 5 feet. This type of trellis is also called the hedgerow trellis and requires canes to be tied to the wire. Train berries on a two-wire trellis by tying the floricanes (second-year fruit producing canes) in a fan shape on the wires where they will get optimal sunlight. Once the primocanes (first-year fruit producing canes) develop, they are tied in among the other canes. Or tie floricanes straight up and down on the wires during late winter or early spring. When the primocanes develop, they are tied over the existing canes. Berry canes last only two years.
A T-bar trellis works well to keep heavy berries off the ground. Two 6-foot posts are sunk 1 foot into the ground at each end of a berry row. A 30-inch piece of post is screwed to the top middle of each post to make a "T" shape. A length of 16 gauge wire is threaded from each end of the cross bar to the ends of the other cross bar at the other end of the row. A double cross trellis is made with 18-inch crossbars at 5 feet or the top of the post and another at 3 feet with canes growing inside the two wires for extra strength. Some T-bars are only made 3 1/2 to 4 1/2 feet high to accommodate lower growing canes. Long rows can be equipped with several T-bar trellises placed 20 feet apart. Tie canes to the wires or let them grow inside of them.
A V-trellis is shaped like the letter "V." They are situated at both ends of a row of canes by inserting two posts into the ground at a 30-degree angle 3 1/2 feet apart in a "V" shape. The height of the trellis should be about 3 1/2 feet. Wire is stretched from the top of each post on one end of the row to the top of each post on the other end. This trellis allows newer primocanes and older florocanes to get the same amount of light by growing in between the wires.