How to trellis raspberries?

Growing Raspberries On A Trellis: Training Trellised Raspberry Canes

Of course, you can grow raspberries without any support, but a trellised raspberry is a thing of beauty. Growing raspberries on a trellis improves fruit quality, makes harvesting much easier and reduces the incidence of diseases. Without training, the raspberries tend to grow every which way, making harvest and pruning a chore. Got your attention? Read on to find out how to trellis raspberry plants.

How to Trellis Raspberry Plants

Training raspberries to grow up a support doesn’t have to be complicated. A trellised raspberry plant may be composed of posts and twine. Space the posts around 15 feet (4.5 m.) apart and then support the canes with the twine. Of course, this should be viewed as a temporary trellis system and because the plants are perennials, it might be better to build something more permanent from the get go.

In the spring after pruning, gently tie the raspberry canes to the support wires using twine or cloth strips. This will allow for better light penetration into the center of the plants, which will promote shoot development and, thus, a larger yield of berries.

Growing raspberries on a trellis in this manner makes harvesting so much easier and facilitates pruning since trellising encourages new cane growth in the center rather than just along the outer edges of the hedgerow. Plus, some varieties such as the summer bearing ‘Dorimanred’ really require trellising to support their trailing growth habit.

I have always had a thing for raspberries. They are much heavier yielding, significantly easier to grow and, to my mind, just as good (if not even better) in the flavour stakes than the mighty strawberry.

I have no idea why more people don’t grow them. From just three plants I get more fruit than my family and I can ever eat, in exchange for little more than 10 minutes of pruning a year, plus the effort it takes to pick them.

If you are already a convert, here is a simple trick that can greatly extend the fruiting season of the autumn kind for really no extra work.

If you follow all the old-school gardening books, the standard advice is to snip back autumn-fruiting raspberries right down to ground level in February. This super straightforward hacking back then encourages the plant to develop brand new, vigorous growth from below ground, which then matures late in the year, thus giving you a harvest from August onwards. In some varieties this continues right up until the first frosts.

If, however, you essentially treat them like summer-fruiting types, only reducing half of these canes to ground level, the plants will respond by producing two flushes of fruit: once in the autumn, as per usual, from the new growth, but also one much earlier in the year from canes that matured the summer before.

In fact, with many “autumn” raspberry varieties, the only difference between them and the “summer” fruiting types is how we choose to prune them, not actual genetics. Adopting this strategy, in my experience, is also a pretty nifty trick if you have inherited plants and have no idea which of these categories they fall into. It eliminates the confusion, hassle and constant rechecking of labels. Don’t know which are which? No problem, just prune them all in February the same way and you’ll be fine.

All I do is start by snipping out the old canes, upon which fruit was produced the previous summer, right down to ground level. These are easy to identify as instead of being firm and green like new growth, they are dry and brown – a tell-tale sign that these branches are now dead and will not produce more flowers or fruit. With the remaining healthy growth, keep the six strongest canes and remove all the rest, snipping them right down to the ground, just as you did with the dead ones. Scatter the soil around the canes with a thick layer of mulch to suppress weeds, and add a scattering of high potash feed, such as dried kelp, and that’s it! You are good to go.

Pick of the crop: autumn varieties for flavour

Autumn Bliss Often dismissed as a novelty due to its yellow hue, this is sweet with a heavy crop of berries.

Joan J Sweet and aromatic, on mercifully spine-free plants.

Polka As delicious as it is generous, with yields double that of many other cultivars.

Email James at [email protected] or follow him on Twitter @Botanygeek

How to grow raspberries

About raspberries

Raspberries are best grown from bare-root plants in the autumn. There are lots of different varieties available, which bear fruit at different times. The majority are harvested between early and late summer, while others are grown for their autumn berries.

What to do

Soil preparation

  • Get the planting site ready by removing weeds and digging in plenty of well-rotted manure a few weeks before planting.

Making supports

  • Raspberries are best grown against supports. In a large garden or allotment, hammer two 2.4m (8ft) tree stakes into the ground 60cm (24in) deep, about 3m (10ft) apart.
  • If growing summer varieties, drill holes into the posts and stretch three rows of galvanised wires (12 gauge) between them – these should be 76cm (30in), 106cm (42in) and 167cm (66in) above the ground and held in place by straining bolts, which can be tightened with a spanner.
  • If you have an autumn variety, there’s no need to add the top wire.
  • If you have a tiny garden, grow plants up a single tree stake. Hammer a stout 2.4m (8ft) stake into the ground and plant two raspberry canes at the base. Allow 12 canes to grow up and keep in place with garden twine.

Planting out

  • The planting depth is important with raspberries and as a rule of thumb, aim for the old soil mark on the stem to be at the same level as the ground after planting. To do this, dig a shallow hole, about 30cm (1ft) wide and 8cm (3in) deep.
  • Spread out the roots and cover with soil, firming as you go. Plant canes 40cm (16in) apart. Cut canes down to 30cm (1ft) above the soil, pruning above a bud, and water well.

Pruning and training

  • Prune canes that held fruit in summer during the autumn, cutting them right back to the ground. Tie in about eight of the strongest new canes from each plant to fruit next year, and remove the rest.
  • In mid-winter, cut back lanky top growth so canes are about 15cm (6in) above the top wire.
  • Prune autumn fruiting varieties in mid-winter, cutting the old canes back to ground level. Tie in new stems to the supporting wires as they grow, using garden twine.

Looking after the crop

  • Raspberries are a hungry and thirsty fruit. Scatter general purpose granular fertiliser over the soil in spring and mulch with well-rotted farmyard manure.
  • Keep plants damp, especially during dry weather.

Harvesting

  • Pick fruit regularly when it’s firm. Pull the raspberries gently from the plant, leaving behind the plug that held it in place.

Watch video

Follow Toby Buckland and Joe Swift planting raspberry varieties to grow for a tasty crop in summer and autumn.

Five to try

Training and Trellising Raspberries

Raspberry plants are relatively easy to grow. They are also hardy and productive in most parts of Iowa. If given good care, a 100-foot-long row of red raspberries can produce 100 to 150 pints of fruit. Proper training and trellising of raspberry plants help insure a good fruit crop.

Red raspberry plants should be maintained in a 1- to 2-foot-wide hedgerow. Remove any suckers that grow outside the hedgerow with a rototiller or spade. Do not allow red raspberries to develop into a wide, solid patch. Cultural practices become extremely difficult and crop yields are reduced when red raspberries grow into a large, dense thicket. Black and purple raspberries grow in clumps. The new shoots (primocanes) of black and purple raspberries need to be pinched when they reach a height of 36 to 48 inches. If allowed to grow unpinched, the canes grow long and fall onto the ground. These canes often root and produce new plants where the tips touch the ground. Tip-layered plants crowd the existing planting and make cultural practices more difficult. Any tip-layered plants should be removed.

Red, black, and purple raspberries can be supported with a trellis. A trellis keeps the canes off the ground. This is especially important when the plants are laden with fruit. The fruit on trellised plants are cleaner and easier to pick. A trellis also reduces crop losses due to storms and facilitates other cultural practices.

There are several different trellis systems. A two-wire permanent trellis is commonly used for raspberries in the home garden. Its construction requires wooden posts, No.12 or 14 galvanized wire, and 2- by 4-inch lumber. The wooden posts should be 3 to 5 inches in diameter and 6 to 8 feet long. Posts should be set 2 to 3 feet into the ground and spaced 15 to 20 feet apart. Near the top of each post, nail or bolt a 24- to 30-inch-long crosspiece. Then run or attach the galvanized wire through the ends of each crosspiece and down the entire length of the row. The two wires should be spaced about 2 feet apart and positioned 3 to 4 feet above the ground.

A temporary trellis may be constructed of posts and twine. Space the posts about 15 feet apart and support the canes with twine. This temporary structure is most suitable for fall-bearing red raspberries grown exclusively for the fall crop.

If utilizing a permanent trellis system, carefully pull and tie the canes of black, purple, summer-bearing red raspberries, and fall-bearing red raspberries (when grown for 2 crops) to the support wires after pruning in the spring. Use twine or cloth strips to tie the canes to the wires. Tying the canes to the trellis wires allows for better light penetration into the center of the row and promotes stronger shoot development. Also, harvesting fruit is easier because the tied canes are more accessible.

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