--- title: "Blackberry and Raspberry Trellis: Heights, Spacing, Build" description: Blackberry and raspberry trellis heights, post spacing and wire by berry type, from extension guides, plus a weekend build and how to train canes on the wires. image: https://growperma.com/hubfs/blog/images/gp-1137-hero-berry-trellis-20260925-053040.webp --- [Skip to content](https://growperma.com/blog/blackberry-raspberry-trellis#main-content) [![GrowPerma Logo](https://growperma.com/hs-fs/hubfs/icon-512.png?width=40&height=40&name=icon-512.png)](https://growperma.com/) - [Blog](https://growperma.com/blog) - [About](https://growperma.com/about) [Join the Weekly Dig](https://growperma.com/newsletter) - [Blog](https://growperma.com/blog) - [About](https://growperma.com/about) [Join the Weekly Dig](https://growperma.com/newsletter) ![Raspberry canes held between wires on a wooden T-trellis with ripe berries and a gardener tying a cane with soft twine](https://growperma.com/hs-fs/hubfs/blog/images/gp-1137-hero-berry-trellis-20260925-053040.webp?width=1200&height=520&name=gp-1137-hero-berry-trellis-20260925-053040.webp) In This Article Table of Contents ![Peter Vogel](https://growperma.com/hubfs/Peter%20Vogel%20Portait.png) Peter Vogel Peter Vogel is the founder of GrowPerma, bringing together evidence-based gardening advice with permaculture principles. When he's not writing about companion ... [Companion Planting](https://growperma.com/blog/tag/companion-planting) September 25, 2026 # Blackberry and Raspberry Trellis: Dimensions by Type and How to Build One Match the trellis to the plant, not to the picture you saw online. Erect and semi-erect blackberries do fine on two wires at about 3 and 5 feet, as [NC State Extension](https://content.ces.ncsu.edu/blackberries-for-the-home-garden) sets them for home gardens. Trailing blackberries want the top wire near 6 feet and room to spread, 6 to 8 feet between plants. Summer-bearing raspberries need a top wire around 5.5 to 6 feet with a lower pair of training wires to hold the row narrow. Every version uses the same parts: sturdy end posts, 12-gauge high-tensile wire, and a way to tighten it again each spring. Below: a dimension table by berry type, a build that takes a weekend, how to train canes onto the wires once it is up, and the mistakes that turn a good trellis into a tangle by year three. 3 + 5 ft Two-wire heights, erect blackberries NC State Extension 5.5–6 ft Top wire, summer raspberries OSU Extension 12 ga High-tensile trellis wire OSU Extension 3–4 in. End post diameter OSU Extension ## Which Trellis Does Your Blackberry or Raspberry Need? Two questions decide it. How does the cane grow: upright, arching, or sprawling along the ground? And when does it fruit: on last year's canes (summer-bearing, called floricane types) or on this year's (fall-bearing, primocane types)? Get those two right and the dimensions follow. | Berry type | Trellis | Wire heights | Plant spacing | | --- | --- | --- | --- | | Erect and semi-erect blackberries | Two-wire on single posts | About 3 ft and 5 ft | 3–4 ft | | Thornless blackberries (Mid-Atlantic) | Two-wire | Low wire 1.5–3 ft, top 5–6 ft | Posts 20–25 ft apart | | Semi-erect blackberries, more wire | Double T: 4 ft top crossarm, 2–3 ft lower crossarm | Four wires, two per crossarm | As above | | Trailing blackberries | Two-wire, posts 6 ft above ground | About 4.5 ft and just under 6 ft | 6–8 ft | | Summer-bearing red raspberries | Top wire plus paired training wires on 12–18 in. crossarms | Top 5.5–6 ft, training wires near knee height | About 24 in. | | Black raspberries | Same idea, fewer canes per plant | As red raspberries | About 30 in. | | Fall-bearing raspberries, mowed each winter | Simple temporary T-trellis often enough | Enough to keep the fruiting tops upright | As red raspberries | Sources: [NC State Extension](https://content.ces.ncsu.edu/blackberries-for-the-home-garden); [University of Maryland Extension](https://extension.umd.edu/resource/start-growing-thornless-blackberries-how-prepare-and-select-cultivars-mid-atlantic-fs-2023-0660); [OSU Extension, blackberries](https://extension.oregonstate.edu/catalog/ec-1303-growing-blackberries-your-home-garden); [OSU Extension, raspberries](https://extension.oregonstate.edu/catalog/ec-1306-growing-raspberries-your-home-garden); [Penn State Extension](https://extension.psu.edu/raspberry-production). ![End-view drawings comparing a two-wire trellis, a T-trellis with a crossarm and a V-trellis for blackberries and raspberries](https://growperma.com/hs-fs/hubfs/blog/images/gp-1137-infographic-berry-trellis-types-20260925-053047.webp?width=800&height=600&name=gp-1137-infographic-berry-trellis-types-20260925-053047.webp) The regional guides do not agree to the inch, and they are not meant to. [Washington State's Pacific Northwest handbook](https://extension.wsu.edu/pnw-gardeners-handbook/chapter-9-berries-and-small-fruits/) sets trailing blackberries on two wires 18 inches apart, the top one at 5 feet and the lower at 42 inches. Oregon State goes a little higher. Pick the one from your region and build to it; the difference between 5 and 6 feet matters far less than having the wire tight. Quick answer For most backyards: wooden end posts 3 to 4 inches thick standing about 6 feet out of the ground, steel T-posts every 15 to 20 feet between them, and two runs of 12-gauge high-tensile wire. Put the wires at about 3 and 5 feet for erect blackberries, a little higher for trailing ones. For summer raspberries, add a pair of training wires near knee height on short crossarms to keep the new canes in a narrow row. ## How to Build a Blackberry or Raspberry Trellis A 30-foot row takes a weekend for two people. Build it at planting time or before: once canes are in the ground, digging post holes beside them is a thorny, root-cutting job. 1 Set the end posts and brace them Use wooden end posts 3 to 4 inches in diameter standing about 6 feet above ground, per [Oregon State](https://extension.oregonstate.edu/catalog/ec-1303-growing-blackberries-your-home-garden). The end posts carry all the wire tension, so anchor or brace each one. A post that leans an inch in the first summer lets every wire sag. 2 Add line posts along the row Steel T-posts every 15 to 20 feet (Oregon State) or wooden posts every 20 to 25 feet ([University of Maryland](https://extension.umd.edu/resource/start-growing-thornless-blackberries-how-prepare-and-select-cultivars-mid-atlantic-fs-2023-0660)) stop the wires from bowing under a full crop. Shorter rows may need none. 3 Run 12-gauge high-tensile wire at your heights Oregon State recommends 12-gauge high-tensile wire for cane berries. Fix it at one end post, run it through staples or clips on the line posts, and put an in-line tensioner at the other end. 4 Tension it, then plan to do it again Pull each wire tight enough that a full crop will not drag it down, then re-tighten every late winter before growth starts. Wire stretches, posts settle, and the first sagging summer is usually the second one. ![Gardener tightening a steel trellis wire with a tensioner on a braced wooden end post beside a row of blackberry canes](https://growperma.com/hs-fs/hubfs/blog/images/gp-1137-body1-tensioning-wire-20260925-053041.webp?width=800&height=450&name=gp-1137-body1-tensioning-wire-20260925-053041.webp) The wire and posts are cheapest at a farm or fence supply store, and they will cut the wire to length. The two small parts worth getting right are the in-line wire joiners that let you re-tension without a new run, and a tensioning tool; we compare them in our [trellis guide for every climber](https://growperma.com/blog/cucumber-trellis), which also covers the grape wires that run on exactly the same hardware. The mistake that costs you the third year Building the trellis for the plant you planted, not the plant you will have. A first-year row looks sparse, so the temptation is light posts and one wire. By year three the canes are heavy with fruit, the end posts lean, and a sagging wire drops the whole crop into the path. Build to full size on day one. ## How to Train Blackberries on the Wires A trellis only works if the canes go where the wires are. Blackberries fruit on second-year canes and then die back, so every summer you are managing two generations side by side. ![Thornless blackberry cane tied loosely to a trellis wire with a soft tie and berries ripening from green to black](https://growperma.com/hs-fs/hubfs/blog/images/gp-1137-float-cane-tie-20260925-053052.webp?width=280&height=280&name=gp-1137-float-cane-tie-20260925-053052.webp) **Erect blackberries.** Tip the new canes in summer when they reach about 3 to 4 feet, as Oregon State's small fruit guide advises, so they branch into a bushy, self-supporting shape at wire height. **Trailing blackberries.** Let this year's new canes trail along the ground or bundle them at the base of the row through their first summer, out of the way of the harvest, as the [WSU handbook](https://extension.wsu.edu/pnw-gardeners-handbook/chapter-9-berries-and-small-fruits/) describes. In winter, cut out the canes that fruited, then lift the new ones onto the wires before bud break. ![Trailing blackberry fruiting canes fanned along two wires while new green canes are bundled at ground level beside the row](https://growperma.com/hs-fs/hubfs/blog/images/gp-1137-body2-trailing-blackberry-training-20260925-053045.webp?width=800&height=450&name=gp-1137-body2-trailing-blackberry-training-20260925-053045.webp) There is one of the few measured results on trellis design in this area. In a [University of Arkansas trial](https://smallfruits.org/files/2019/12/2019-SRSFC-RCA-Blackberry-R-10-McWhirt.pdf), the blackberry cultivars 'Ouachita' and 'Osage' on a rotating cross-arm trellis had cull rates more than 50 percent lower than on a standard T-trellis. That is a commercial system, but the lesson carries: how the canes are held changes how much fruit you actually keep. ## How to Train Raspberries on the Wires ![Pruned red raspberry hedgerow in late winter with dormant canes evenly spaced between two parallel wires and straw mulch](https://growperma.com/hs-fs/hubfs/blog/images/gp-1137-float-raspberry-hedgerow-winter-20260925-053054.webp?width=280&height=280&name=gp-1137-float-raspberry-hedgerow-winter-20260925-053054.webp) **Summer-bearing red raspberries** grow as a hedgerow. The [WSU handbook](https://extension.wsu.edu/pnw-gardeners-handbook/chapter-9-berries-and-small-fruits/) ties the fruiting canes to the top wire, leaves them long through the winter, then tops them about 6 inches above the wire in late winter. The new canes grow up through the middle of the row in spring, and the training wires are raised to gather them into a narrow band. **How many canes.** After winter pruning, [Penn State Extension](https://extension.psu.edu/raspberry-production) keeps four to six canes per foot of row for summer-bearing reds, and five to seven canes per plant for black raspberries. Everything else comes out. **Fall-bearing raspberries** are the easy case. If you mow every cane to the ground each winter and take a single autumn crop, a simple temporary T-trellis is often enough, according to Oregon State. If you leave the lower part of the canes for a second, early summer crop, as [Oregon State's primocane guide](https://extension.oregonstate.edu/catalog/pub/em-9422-primocane-fruiting-raspberry-production-central-oregon) describes with four to six overwintered canes per row foot, build the full trellis instead. Why This Works: Design for Airflow, Not Just Support The [University of Arkansas blackberry diagnosis guide](https://uaex.uada.edu/publications/pdf/MP574.pdf) links anthracnose to warm, wet conditions with little air movement. A trellis that holds canes in a narrow, open row is a disease tool as much as a support. That is the permaculture habit of making one element do several jobs: the same wires that carry the crop also dry the leaves after rain and keep the fruit off the soil. One question the extension guides we checked do not answer is which way to run the row. North to south is common practice for even light on both sides, but we found no university source that tests it for cane berries, so treat it as a sensible default, not a rule. Building the same system for grapes or cucumbers? Heights, wire and the hardware that keeps it tight, crop by crop. [See the trellis guide](https://growperma.com/blog/cucumber-trellis) ## Frequently Asked Questions ### How tall should a blackberry trellis be? For erect and semi-erect blackberries, NC State Extension uses two wires at about 3 and 5 feet in home gardens. Trailing blackberries go a little higher: Oregon State sets posts about 6 feet above ground with wires near 4.5 feet and just under 6 feet, and Washington State uses 42 inches and 5 feet. The University of Maryland suggests a lower wire between 1.5 and 3 feet and a top wire at 5 to 6 feet for thornless types. Pick the guide from your region and build to it. ### What is the best trellis for raspberries? For summer-bearing red raspberries, a hedgerow trellis with a top wire at about 5.5 to 6 feet and a pair of training wires near knee height on 12- to 18-inch crossarms, as Oregon State Extension describes. The training wires hold the new canes in a narrow row. Fall-bearing raspberries that are mowed to the ground every winter often need only a simple temporary T-trellis. Black raspberries use the same idea with fewer, stouter canes per plant. ### How far apart should trellis posts be for berries? Oregon State Extension spaces steel T-posts 15 to 20 feet apart along a blackberry row, with heavier wooden end posts 3 to 4 inches thick. The University of Maryland suggests 20 to 25 feet for thornless blackberries, and Washington State's handbook uses 25 to 30 feet for trailing types. Closer spacing costs a few more posts and saves you a sagging wire in a heavy year, which is the better trade on a short backyard row. ### What wire should I use for a blackberry or raspberry trellis? Oregon State Extension recommends 12-gauge high-tensile wire for cane berries, the same wire used on grape trellises. Its blackberry and raspberry guides give the same recommendation, so one roll covers either row. Fix it at one end post, run it along the line posts, and put a tensioner at the other end so you can tighten it again each late winter, because wire stretches and posts settle in the first years. ### Do fall-bearing raspberries need a trellis? Not always. If you mow every cane to the ground in winter and take one autumn crop, Oregon State Extension notes that a simple temporary T-trellis is often enough to keep the fruiting tops upright and off the ground. If you keep the lower part of the canes for a second, early summer crop, the canes stand for over a year and carry two crops, so build the full permanent trellis you would use for summer-bearing raspberries. ### How many raspberry canes should I keep? After winter pruning, Penn State Extension keeps four to six canes per foot of row for summer-bearing red raspberries and five to seven canes per plant for black raspberries. Remove the rest at ground level, starting with the thinnest and any that are damaged or diseased. A thinned row dries faster after rain, which matters for fungal disease, and is much easier to pick than a crowded one, even if it looks sparse in March. Get the Weekly Dig One practical permaculture guide a week, written for gardeners who do this on weekends: what to plant together, what to build, and which advice is folklore. Free, no spam, unsubscribe any time. [Join the Weekly Dig](https://growperma.com/newsletter) [Browse All Guides →](https://growperma.com/blog) A berry trellis is a twenty-year structure, so it is worth planning what grows around it. Our [raspberry and blackberry companion guide](https://growperma.com/blog/companion-planting-raspberries-and-blackberries) covers the plants that belong at its base, [when to prune berry bushes](https://growperma.com/blog/when-to-prune-berry-bushes-timing-by-type-and-zone) covers the timing, and [berry bushes for the food forest shrub layer](https://growperma.com/blog/best-berry-bushes-for-food-forests-the-shrub-layer) shows where cane berries fit in a larger design. More in our [companion planting guides](https://growperma.com/blog/tag/companion-planting). ## Resources - [NC State Extension: Blackberries for the Home Garden](https://content.ces.ncsu.edu/blackberries-for-the-home-garden) - [Oregon State University Extension: Growing Blackberries in Your Home Garden (EC 1303)](https://extension.oregonstate.edu/catalog/ec-1303-growing-blackberries-your-home-garden) - [Oregon State University Extension: Growing Raspberries in Your Home Garden (EC 1306)](https://extension.oregonstate.edu/catalog/ec-1306-growing-raspberries-your-home-garden) - [Oregon State University Extension: Primocane-Fruiting Raspberry Production in Central Oregon](https://extension.oregonstate.edu/catalog/pub/em-9422-primocane-fruiting-raspberry-production-central-oregon) - [University of Maryland Extension: Start Growing Thornless Blackberries (FS-2023-0660)](https://extension.umd.edu/resource/start-growing-thornless-blackberries-how-prepare-and-select-cultivars-mid-atlantic-fs-2023-0660) - [Washington State University Extension: PNW Gardener's Handbook, Berries and Small Fruits](https://extension.wsu.edu/pnw-gardeners-handbook/chapter-9-berries-and-small-fruits/) - [Penn State Extension: Raspberry Production](https://extension.psu.edu/raspberry-production) - [University of Arkansas Cooperative Extension: What Is Wrong With My Blackberry? (MP574)](https://uaex.uada.edu/publications/pdf/MP574.pdf) - [Southern Region Small Fruit Consortium: Rotating Cross-Arm Trellis for Southeastern Blackberry (2019)](https://smallfruits.org/files/2019/12/2019-SRSFC-RCA-Blackberry-R-10-McWhirt.pdf) **Tags:** [Companion Planting](https://growperma.com/blog/tag/companion-planting) ## Related Articles ![Cucumber vines on a green A-frame trellis over a raised bed with straight cucumbers hanging and a hand picking one, pole beans on a teepee behind](https://growperma.com/hs-fs/hubfs/blog/images/gp-1136-hero-cucumber-trellis-20260924-180613.webp?width=400&height=220&name=gp-1136-hero-cucumber-trellis-20260924-180613.webp) 24 Sep [Companion Planting](https://growperma.com/blog/tag/companion-planting) #### Cucumber Trellis: How Tall, Which Kind, and What to Buy for Every Climber Peter Vogel ![Late autumn raised bed of frost-touched collard greens interplanted with sweet alyssum and a row of dill going to seed behind](https://growperma.com/hs-fs/hubfs/blog/images/gp-0548-hero-collard-bed-20260908-064751.webp?width=400&height=220&name=gp-0548-hero-collard-bed-20260908-064751.webp) 8 Sep [Companion Planting](https://growperma.com/blog/tag/companion-planting) #### Collard Companion Plants: What the Evidence Supports Peter Vogel ![Red seven-spotted ladybugs feeding on flowering dill and yarrow umbels in a late summer vegetable garden with cosmos and calendula behind](https://growperma.com/hs-fs/hubfs/blog/images/gp-0544-hero-ladybugs-on-dill-20260907-143702.webp?width=400&height=220&name=gp-0544-hero-ladybugs-on-dill-20260907-143702.webp) 7 Sep [Companion Planting](https://growperma.com/blog/tag/companion-planting) #### Plants That Attract Ladybugs (and What They Eat) Peter Vogel ![GrowPerma](https://growperma.com/hubfs/icon-512.png) Gardens That Work Like Forests — the smart-friend guide to permaculture for normal backyards. #### Explore - [Blog](https://growperma.com/blog) - [Companion Planting](https://growperma.com/blog/tag/companion-planting) - [Soil & Composting](https://growperma.com/blog/tag/soil-composting) - [Food Forests](https://growperma.com/blog/tag/food-forest) - [Permaculture](https://growperma.com/blog/tag/permaculture-foundations) #### Resources - [About](https://growperma.com/about) - [All Articles](https://growperma.com/blog) #### Legal - [Imprint](https://growperma.com/imprint) - [Privacy Policy](https://growperma.com/privacy-policy) - [Affiliate Disclosure](https://growperma.com/affiliate-disclosure) - Cookie Settings As an Amazon Associate I earn from qualifying purchases. 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