Raspberries

• Raspberries are a fruit packing loads of flavour and they are exceptionally healthy being full of anthocyanins.
• Easy for every gardener to grow but get the soil right !

If ever there was a summer treat, then delicious home-grown raspberries must be it. They are extremely hardy and have no trouble with frost, like most soils, will tolerate a bit of shade and even bad pruning. They really are very easy to grow which seems a bit daunting when they do not produce the fruit you imagine. However there are a few things to consider which we will cover and then they really do become straightforward.

One of the reasons we grow them at home is because the fruit has such a short shelf-life. Unless modified packaging is used, because it will only last a few days at best in the refrigerator, the best reason is actually to grow them.

The varieties to choose can either be early season, mid-season or late season types, and should be planted at the correct time of year, which will range from November to April. By choosing the right varieties, you could be picking raspberries from mid-June to the end of September.

Raspberries like cool and damp conditions. One of the reasons why they are grown so successfully in Scotland. We know they can tolerate most soils but a slightly acidic one is best. being shallow-rooted means they need good mulching from compost for the best results.

Follow our advice and you could soon be enjoying the wonderfully tart flavour of these tempting berries. If anyone says its about the raspberry canes, just tell them that it is all about soil preparation for the site – pure and simple. We’ll explain this later on.

Uses

They can be frozen or used in desserts and jams. This fruit is suitable for use all year round. They are an excellent crop to grow because once they are established they crop heavily. It is estimated they can produce up to 1.5kg (or over 3lbs) of fruit annually from just one cane.

Choosing Canes

The fruit flourishes just about anywhere. It’s worth remembering that it is a cane which is planted and not a seed,

When you choose raspberry plants, choose wisely. In the UK, select the best quality which is virus-free stock from a reputable nursery or stockist. Check the catalogues from people like Pomona Fruits. They recommend hand graded raspberry canes from selected sites which have been inspected by DEFRA for pests and diseases. These should be certified in the UK by the Plant Health Propagation Scheme (PHPS).

Canes are available from late November to the end of April.

Planting Raspberries

The canes, usually bare-rooted are available between November and March. They should be planted in March into good fertile, well-draining soil but not necessarily in full sun although some growers believe this is ideal. A soil pH of between 6.0 and 6.7 is best. I prefer some light shade to reproduce the appropriate growing conditions for this fruit but it is not an absolute.

The key to good raspberry crops is making sure the soil preparation is correct. Make sure all perennial weeds are removed. Raspberries have shallow roots so any hoeing is out of the question because of the damage that is possible.

Dig a trench 40cm (16in.) wide and deep. Add plenty of well-rotted manure or compost into the trench to really feed the plants. Not only are you feeding the roots but keeping the moisture locked in especially whilst the freshly planted canes get themselves established. Please do not use mushroom compost because it produces alkaline soil.

It is important to plant the canes in ground that has not had this fruit or other Rubus plants like blackberries before. Apparently, if this is ignored, the previous crop will have left the dormant replant virus in the ground which will suppress growth of subsequent plantings. This pathogen can remain viable for up to 30 years, so it’s best to follow this particular advice more than anything.

Soak the roots of bare canes for one or two hours and then apply something like Rootgrow™ mycorrhizal fungi to both roots and the growing hole before planting.

Plant as close as 40cm (16in.) apart although 45cm (18in.) is better, with a gap of 1.5m (5ft) between rows if this is required. The roots should be spread out to the depth indicated by the soil mark on the main stem, or up to 1cm deeper. Tread firmly and water in thoroughly.

After planting, prune the stem back to about 5cm (2in.) above the soil level.

Continued and On-Going Care

In dry weather, water the canes thoroughly once a week, especially during their first spring and summer. Keep the area around the canes weed free, particular during their first year. An annual mulch of well-rotted compost greatly improves moisture retention and soil structure, and helps to suppress unwanted weeds. Feed the plants liberally in spring using fruit fertiliser.

All but the shortest of raspberry varieties will require support from the second year to keep the the fruit up high and away from the mud. The ways to do this are two-fold. Either tie the canes loosely in clumps around single stakes, or tie them to two or three horizontal wires, or between pairs of wires erected between 75cm and 1.5m above ground depending on the variety.

Pruning

To encourage vigorous new growth and help establishment, cut all stems back on summer fruiting varieties to 30cm above ground at the time of planting. For future growing, the yields depend on the previous season’s canes which die back to ground level. Pruning should also be conducted in August and September by cutting out growth that has just produced a harvest. Train in new canes, tying them to their support wires from where they will produce their fruiting spurs the following summer.

If autumn fruiting canes are not cut down during the winter, they will continue growing so that they produce a further crop on the same canes the following summer. they are just as productive as before. These do need to be cut down when the summer crop is finished, and the new canes that emerged earlier in the season will carry the autumn crop for later harvests.

Harvesting Autumn Raspberries

Raspberries are one of those fruits which can be collected in prolific quantities if the weather conditions are right. My first summer variety was ‘Glen Fyne’ which cropped from mid June to late July. We also planted an autumn row of ‘Polka’ and ‘All Gold’ and these are continuing to produce fruit into mid-September. The first frosts in the UK will finish off any further fruit formation and ripening. I have placed a double layer of fleece over the canes. These are held off the canes with  just bamboo canes to extend the fruiting season a little but freezing cold soon demolishes the fruit season.

Most new raspberry canes take a year to settle in properly before they star fruiting. We planted 12 canes each of summer and autumn producing fruit. Each plant is checked twice a week and any fruit picked at peak ripening.

Any over-ripe fruit is not left to moulder in the fridge, they get eaten or frozen. Separating the fruit from the green plug is not easy but given it squishes away readily, that fruit gets used in smoothies, apple dishes and anything that takes a raspberry hit.

Have a surplus of fruit ? Just spread on a tray.

Pests & Diseases Of Raspberries

Generally these are trouble-free ! The summer fruit producing cultivars are more prone to diseases than the autumn fruiting variants.  

The most damaging situation occurs with the larvae of raspberry beetles. These reveal themselves as small dry patches usually on the top of the fruit. Careful inspection then shows a small white grub inside the fruit which is not what anybody wants. Spraying is not advised because of timing it. The females lay their eggs when the flowers are open and once inside the developing fruit are not easy to control. We recommend pheromone traps which attract the male fly and kill it. These are better than sprays and are hung above the crop as soon as the first buds begin to show themselves and start to open.

Use chemicals strictly according to the manufacturer’s instructions.

A developing pest problem in the United Kingdom which has started in the south-east is the Drosophila fruit fly. It has appeared on a number of fruits. The maggots cause the berries to quickly turn to mushiness, often once they are picked. Use traps which can be prepared using an old bottle with a yellow sticky trap inside the bottle and partly filled with apple cider vinegar.

Autumn cultivars are less troubled by pests like raspberry beetle. They flower much later and so miss the egg-laying of the beetle.

Viruses affect all raspberries. All canes sold in the UK are now certified as virus-free.

When plants have been in the same spot for a number of years they tend to pick up viruses from feeding pests like aphids such as blackfly and greenfly.  It will get into older canes which are 8 years old or more. The leaves become mottled and there is a loss of productivity. The only way is to uproot and burn. Replace canes but grow on a new site.

The most common issue is actually mineral deficiency. This is most prevalent when canes are grown on sandy and alkaline soils. A lack of nitrogen and magnesium causes the leaves to turn yellow but the leaf veins stay green. Mulching stops the minerals leaching away from the soil. All raspberries will enjoy summer foliage feeds using a seaweed solution. I find a spray with Epsom salts which is magnesium sulphate in the spring also works wonders.

Varieties

Try Pomona Fruits who sell a wide range of fruit plants to suit any kitchen garden or allotment. www.pomonafruits.co.uk

Summer Fruiting/Early Season

Cultivars that produce their fruit in the early part of the season are called ‘early season’ or summer fruiting varieties. This compares to those that are late season or autumn fruiting. 

cv. ‘Cascade Delight’. An impressive new late summer variety producing heavy crops with exceptionally large fruits and a superb flavour. It shows good resistance to root rot disease, so is able to cope with wetter soils. Season: early July to early August.

cv. ‘Malling Juno‘. Produces medium to large raspberries with a firm texture and delicious sweet flavour. Ideal when eaten fresh. The spine-free canes are leafy, easy to handle and prune. The fruits are well presented and easy to harvest. This variety crops from early to late June and even earlier if grown under cover. Plants have excellent disease resistance.

cv. ‘Glen Fyne‘. Excellent mid-season raspberry tipped to be the next great variety for the garden. One of the tastiest raspberries ever tasted with a sweet and richly aromatic flavour. The bright red fruits are quite firm and slightly conical in shape. the canes are moderately vigorous and have the advantage of being spine free.

Mid-Season Cultivars

cv. ‘Tulameen Pearl’ – A vigorous new strain which has come onto the market. It is already creating a stir with fruit that has excellent flavour. It has a high yield with large firm fruit which keeps well once picked. Has a exceptional flavour. Good disease resistance!

Autumn Fruiting

cv. Autumn Bliss – I suspect this is the best known autumn variety and still outranks many of the other varieties. It produces large crops, is reliable and easy to grow and look after. The fruit is softer than newer varieties. Will keep on cropping from mid-August until hit by the first frosts.

cv. ‘Himbo Top’ – produces some of the largest fruit known and a very good yielder with heavy cropping from September onwards. The fruit is some of the richest in flavour and a good one for juices. growth can be vigorous – almost too vigorous so needs plenty of support.

cv. ‘Joan J’. The outstanding new spine-free and autumn flowering fruiting primocane raspberry. One to be recommended now above all the others. Has great flavour with exceptional berry size which makes this variety so superlative. The berries are 30 per cent larger than Autumn Bliss and they freeze exceptionally well. The canes are short and sturdy and may require supporting in sheltered gardens. Season: late July – Oct. Plant canes 40cm (16in.) apart.

cv. ‘Polka’. The multi-award winner at the National Fruit Show 2018. Polka has exceptional fruit quality and the large, medium red berries are full of fragrant, zesty flavour. The cultivar was bred in Poland with ‘Atumn Bliss’ as one of its parents. The virtually spine-free canes will yield double the crop of some varieties and crops up earlier, from late July to October. ‘Polka’ even grows well on less desirable soils.

Yellow Varieties

cv. ‘All Gold’ – a real treat and should be included in the garden amongst the red coloured cultivars. Produces some of the best flavoured fruit but is also yellow and in great abundance. Very distinct in sweetness. Makes a yellow raspberry jam which is widely admired by connoisseurs and epicureans alike.