Pruning raspberries: How to do it

Cutting back raspberries: The right time

To ensure that your raspberries produce a rich harvest every year, you should prune them once a year. However, pruning is not only important for a good harvest, but also to prevent diseases on your raspberries. We explain below when the right time to prune is.

When to cut raspberries?

To determine the right time to prune raspberries, it is important to know which variety of raspberry you are dealing with. There are summer, fall and double-bearing raspberry varieties that bear fruit at different times and on canes of different ages. This has an impact on the best time for pruning and which canes should be shortened and when. You can find out which raspberry varieties there are and how to grow them in your garden in our article Planting raspberries: location, cultivation & neighbors.

Pruning raspberries in the fall

The old canes of summer raspberries that have borne fruit this year are best cut off close to the ground immediately after harvesting in August. They are worn out and should be removed, as they take away the plant's strength, which it would otherwise put into the formation of new canes and fruit.

Autumn raspberries can be pruned in late fall, but before winter, as soon as they have lost their leaves.

Pruning raspberries in spring

However, as autumn raspberries can sometimes bear fruit until the end of October, depending on the variety, you may prefer to prune them in February and March. Otherwise, you will deprive your raspberry plants of the strength and energy they need to survive the winter.

In spring, as soon as the last frosts have passed, a second, smaller pruning is carried out on summer raspberries. The young canes are thinned out and possibly shortened if they are a little too long.

In spring, the old, worn canes of double-bearing raspberries are pruned and any canes that are too dense are thinned out to provide more vigor and better aeration.

Prune raspberries correctly: What you should keep in mind

There are a few things to bear in mind when pruning raspberries. When pruning and thinning, it is important to cut the canes close to the ground. This prevents the transmission of diseases. Weak canes should also be cut off when pruning so that only the strongest canes remain. In general, the more canes there are on your raspberry bush, the later the bush will bear fruit. Ideally, you should also know which raspberry variety you have in your bed. Summer and autumn raspberries bear fruit on canes of different ages. You can find out how to tell the different raspberry varieties apart in the next section.

Raspberry varieties: an overview

In contrast to summer raspberries, which can grow up to 2.5 m tall, autumn raspberries are usually only 1.5 m tall. While summer raspberries form their fruits on the biennial canes as early as June and July, autumn raspberries bear their berries on the annual canes between August and November. You can recognize the different shoots of summer and autumn raspberries by the fact that the young shoots of summer raspberries grow in the first year but do not produce flowers. The shoots of autumn raspberries, however, already bear flowers and fruit in the first year.

If you are not sure which type of raspberry you are dealing with, prune your raspberries as if they were summer raspberries. In general, you should therefore prune all shoots that have already borne fruit. This will give you at least one summer harvest next year. If your raspberries then bear fruit again in the fall, you know that they are fall raspberries.

Cutting summer raspberries

While the biennial shoots of summer raspberries form the fruit, the new, green, annual shoots grow for next year's harvest. Therefore, you must never cut off the annual shoots when pruning after the harvest. Otherwise your harvest will fail the following year. The old, brownish, two-year-old sh oots that have just produced the harvest, on the other hand, are cut off close to the ground in around August. If your raspberries are still quite young, you can be a little more careful when harvesting. If present, you can leave a few buds that are close to the ground and cut your raspberries back to around 5 - 10 cm.

Thinning pruning for your summer raspberries in spring

At the same time as pruning the old canes (i.e. in August after the harvest) or in spring (end of February/beginning of March), thinning and pruning can be carried out. Around 7 - 10 shoots per running meter are sufficient for a good harvest. This increases the yield and fruit size, as the plant can put its strength into the remaining shoots. It is best to choose strong shoots that are not too close together and that grow in different directions. All other shoots, especially weak or diseased shoots, are shortened close to the ground.

Further pruning can also be carried outbetween March and May if necessary: summer raspberries can form canes up to 2.5 m long. To prevent the canes from growing over your head and to keep them healthy, you can prune the canes back to around 1.5 m during this time. Side shoots can also be cut back to 1 - 2 buds.

If your summer raspberries have already produced their first shoots in April and May, but there is another late frost, it is best to cut off these fresh young shoots. Otherwise, these shoots will most likely die in winter and your harvest will fail the following year.

Pruning autumn raspberries

Autumn raspberries are somewhat easier to prune than summer raspberries. Either after harvesting in the fall, but before the first frost as soon as the leaves have fallen, or preferably in the spring (end of February to mid-March), simply cut off all the shoots of your autumn raspberries close to the ground. Autumn raspberries bear their fruit on the annual canes. This means you don't have to pay attention to the age of your canes and can simply cut off all the shoots.

To extend the harvest period of your autumn raspberries, you can also leave a few canes about 20 - 30 cm high. Like summer raspberries, these already bear a few first raspberries in June and July. However, the more canes you leave standing, the smaller the fall harvest of your raspberries will be later on. This is also the principle behind two-timer raspberries.

Cut 2x bearing raspberries (e.g. Sugana Two-Timer raspberries)

Double-bearing raspberries, e.g. the Sugana Two-Timer variety, bear fruit twice a season. They are pruned once in spring (end of February to mid-March). Then the two-year-old shoots that bore fruit the previous year are cut off close to the ground(about a third) and the remaining shoots are only shortened slightly (the part that bore fruit the previous year). At the end of July/August, shoots that have just borne fruit can also be cut off close to the ground. Raspberries that bear fruit twice are a kind of mixture of summer and fall raspberries. After pruning in spring, the biennial canes that were left standing will produce fruit again in June/July, while the new annual canes will already produce fruit on their uppermost part in August. However, if all the biennial canes have been left standing, the plant no longer has enough strength for a good second harvest in August. Canes that are too dense should also be thinned out to ensure good ventilation and light.

Forgetting to cut raspberries: Do you have to cut raspberries?

If you forgot to prune your raspberries last year or in spring this year, it's not too bad at first. However, your harvest may be smaller this year. However, your plant will recover after the next pruning, which you carry out as planned. If there are any diseased or damaged shoots on your plant, you should cut them off as soon as possible. This will prevent diseases from spreading and ensure that the plant retains enough strength to grow.

Raspberries too long?

The canes of summer raspberries in particular can grow taller than 2 m. These are then cut off in late fall, but preferably in spring (February/March, possibly until May) of the following year a few centimeters above the climbing support, to about 1.5 m. This will give the shoot more strength and stimulate bud formation. However, the young canes should not be pruned during the vegetation period, as this leads to branching and therefore less vigorous canes.

Pruning raspberry bushes for healthy raspberries

Pruning raspberries is recommended for several reasons. Pruning helps against:

• The spread of diseases and pests. Old, thick canes often have cracks in the bark, which can allow germs to penetrate and cause disease. If there are too many canes on a bush, fungal diseases can spread more easily as there is insufficient aeration.
• Spreading raspberry plants in your garden. If raspberries are not pruned, they will spread throughout your garden.
• Ensuring a good harvest. Thin, weak or old shoots rob your plant of strength, which it then cannot put into the formation of new shoots and fruit.
• Depending on how many shoots you leave standing, you can influence the ripening period of your raspberries. If there are more shoots on a plant, the fruit will ripen later.

Do raspberries have brown or yellow leaves?

While diseased shoots should be cut off as quickly as possible, yellowish and brown leaves on raspberry plants are usually just a lack of nutrients. Above all, a lack of magnesium often occurs in raspberries. To prevent yellow leaves, you should therefore feed your raspberries once in autumn and/or spring with a fertilizer containing magnesium. You can prevent brown leaves by generally fertilizing with berry or tomato fertilizer. Proper fertilization helps to protect your plants from diseases. You can find out exactly how to fertilize and care for your raspberries correctly in our article Fertilizing, caring for & propagating raspberries.

Avoid diseases on raspberry plants

To avoid diseases on raspberry plants, you should cut off old canes after harvesting. This will give your plant more strength, making it more resistant to diseases and pests. You should also cut off shoots during the season if they are affected by frost, pests or diseases so that these do not spread to other parts of the plant and cost it additional strength. You should dispose of these shoots in organic waste rather than compost to prevent diseases and pests from spreading.

Do you have other soft fruit in your garden? Find out how to prune gooseberries, currants and strawberries correctly in our articles.

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Photo by Noura Haddad on Unsplash.